Canine Lymphoma: Risk Factors, Symptoms, Diagnosis, and Treatment

Cancer is never “good news” – but this is one of the few malignancies that can go into remission, sometimes for years or even for the rest of the dog’s life.


Lymphoma accounts for 7 to 24% of all canine cancers and approximately 85% of all the blood-based malignancies that occur, making it one of the most common cancers found in dogs. Lymphoma – also referred to as lymphosarcoma – is not a singular type of cancer but rather a category of systemic cancers with over 30 described types.

Lymphoma occurs when there is a genetic mutation or series of mutations within a lymphocyte that causes the cells to grow abnormally and become malignant, ultimately affecting organs and body functions. Lymphocytes are the infection-fighting white blood cells of the immune system and are produced by the lymphoid stem cells in the bone marrow and lymphoid tissue in the bowel. Their role is to prevent the spread of disease, to provide long term immunity against viruses, aid in wound healing, and provide surveillance against tumors.

Lymphocytes are part of the lymphatic system – a network of tissues and organs that help rid the body of toxins, waste, and other unwanted materials. The primary function of the lymphatic system is to transport lymph, a fluid containing lymphocytes, throughout the body. Unfortunately, cancerous lymphocytes circulate through the body just as the normal lymphocytes do.

Although lymphoma can affect virtually any organ in the body, it most commonly becomes evident in organs that function as part of the immune system – the locations where lymphocytes are found in high concentrations – such as the lymph nodes, spleen, thymus, and bone marrow. Swelling occurs when the numbers of cancerous lymphocytes increase; one of the most common sites of accumulation are in the lymph nodes themselves, resulting in an increased size of these structures.

Cancer Terminology

Lymphoma is not to be confused with lymphocytic leukemia. While this disease also starts in the lymphocytes, lymphocytic leukemia results in an invasion of cancerous white blood cells in the bone marrow and blood, rather than in the lymph nodes and other tissues like lymphoma. Leukemia tends to be pretty rare in dogs, though at times dogs can be diagnosed with both leukemia and lymphoma; at Stage V, lymphoma is technically leukemic lymphoma, meaning the cancer is both in organ tissue and in the bone marrow or blood.

Other similar sounding but unrelated conditions include lymphangio-sarcoma, a cancer that originates in the lymphatic endothelial cells; lymphadenopathy/ lymphadenomegaly, lymph nodes smaller than normal or abnormal in texture or shape / abnormal enlargement of the lymph glands; and lymphadenitis, which refers to an inflammation of the lymph nodes typically due to infection from bacteria, viruses, fungi, or parasites, or from toxic or chemical exposures.

Canine lymphomas are similar in many ways to the non-Hodgkin’s lymphomas (NHL) which occur in humans, though dogs are two to five times more likely than people to develop lymphoma. The two diseases are so similar that almost the same chemotherapy protocols are used to treat both, with similar responses reported. NHL has been featured recently in the high-profile cases involving individuals who developed non-Hodgkin’s lymphoma after using the weed killer glyphosate (most highly recognized under its best-selling brand name, Roundup).

Because of its similarity to the human form, canine lymphoma is one of the best understood and well-researched cancers in dogs. It is one of the few cancers that can have long periods of remission, even lasting years, and although rare, complete remission has been known to occur.


The cause of canine lymphoma is not known. It is suspected that the cause may be multifactorial. In an effort to determine what factors affect the possibility of developing the disease, researchers are looking at the role of environmental components such as exposure to paints, solvents, pesticides, herbicides, and insecticides; exposure to radiation or electromagnetic fields; the influence of viruses, bacteria, and immunosuppression; and genetics and chromosomal factors (changes in the normal structure of chromosomes has been reported). It is thought that dogs living in industrial areas could be at a higher risk for developing lymphoma.


Although the direct cause of lymphoma cannot be identified, studies have found that there are certain breeds that are at higher risk of developing the disease. The most commonly affected breed is the Golden Retriever, equally represented by B-cell and T-cell lymphomas (see below).

Other breeds showing increased incidence include the Airedale, Basset Hound, Beagle, Boxer, Bulldog, Bull Mastiff, Chow Chow, German Shepherd Dog, Poodle, Rottweiler, Saint Bernard, and Scottish Terrier. Dachshunds and Pomeranians have been reported as having a decreased risk of developing canine lymphoma.

Lymphoma can affect dogs of any breed or age, but it generally affects middle-aged or older dogs (with a median age of 6 to 9 years). There has been no gender predisposition noted, but there are reports that spayed females may have a better prognosis.

A recent large scale study published in the Journal of Internal Veterinary Medicine (Volume 32, Issue 6, November/December 2018) and conducted by the University of Sydney School of Veterinary Science in Australia, examined veterinary records for breed, gender, and neuter status as risk factors for developing lymphoma. A number of breeds were observed to be at risk that had not been previously identified as being in that category.

The study also demonstrated the opposite: Several breeds previously documented to have an increased risk of lymphoma failed to show an increased risk. Additionally, the study found males had a higher risk overall across breeds, as did both males and females that had been neutered or spayed. Mixed breeds generally had a decreased risk when compared with purebred dogs. While these findings may be inconsistent with other generally accepted risk factors, the study states, “These three factors need to be considered when evaluating lymphoma risk and can be used to plan studies to identify the underlying etiology of these diseases.”


Typically, a dog who gets diagnosed with lymphoma will initially be taken to a veterinarian because one or more lumps have been found under the neck, around the shoulders, or behind the knee. These lumps turn out to be swollen lymph nodes. The majority of dogs (60 to 80%) do not show any other symptoms and generally feel well at the time of diagnosis.

Advanced symptoms depend on the type of lymphoma and the stage and can include swelling/edema of the extremities and face (occurs when swollen lymph nodes blocks drainage), loss of appetite, weight loss, lethargy, excessive thirst and urination, rashes, and other skin conditions. Breathing or digestive issues may be present if the lymph nodes in the chest or abdomen are affected.

Because the lymphatic system aids in fighting infection, fevers are often one of the first indicators of the disease. Additionally, since lymphoma affects and weakens the immune system, dogs may be more susceptible to illnesses, which can lead to complicated health issues. Lymphoma itself, however, is not thought to be painful to dogs.

Lymphoma can occur anywhere in the body where lymph tissue resides and is classified by the anatomic area affected. The four most common types are multicentric, alimentary, mediastinal, and extranodal. Each type has its own set of characteristics that determine the clinical signs and symptoms, rate of progression, treatment options, and prognosis. Furthermore, there are more than 30 different subtypes of canine lymphoma.

  • Multicentric Lymphoma. This is the most predominant type of lymphoma, accounting for 80 to 85% of all canine cases. It is similar to non-Hodgkin’s lymphoma in humans. The first noticeable sign of this form is usually enlargement of the lymph nodes in the dog’s neck, chest, or behind the knees, sometimes up to 10 times their normal size, with the patient not showing any other distinctive signs of illness.

Multicentric lymphoma tends to have a rapid onset and affects the external lymph nodes and immune system; involvement of the spleen, liver, and bone marrow are also common. The disease may or may not involve other organs at the time of diagnosis, but it eventually tends to infiltrate other organs, causing dysfunction and eventually leading to organ failure.

As it progresses, additional symptoms including lethargy, weakness, dehydration, inappetence, weight loss, difficulty breathing, fever, anemia, sepsis, and depression may be observed. This form can also metastasize into central nervous system (CNS) lymphoma in later stages, which can cause seizures and/or paralysis.

  • Alimentary (Gastrointestinal) Lymphoma. This is the second most prevalent form of canine lymphoma, however it is much less common, accounting for only about 10% of lymphoma cases.

Because it is in the digestive tract, it is more difficult to diagnose than the multicentric form. It is reported to be more common in male dogs than females. This type forms intestinal lesions, typically resulting in the manifestation of gastrointestinal-related signs, including excessive urinating or thirst, anorexia, abdominal pain, vomiting, diarrhea (dark in color), and weight loss due to malabsorption and maldigestion of nutrients.

The disease affects the small or large intestine, and it has the potential to restrict or block the passage of the bowels, resulting in serious and complicated health risks or fatality.

  • Mediastinal Lymphoma. This is the third most common type of canine lymphoma, but it is still a fairly rare form. Malignant lesions develop in the lymphoid tissues of a dog’s chest, primarily around the cardiothoracic region. This form is characterized by enlargement of the mediastinal lymph nodes and/or the thymus. The thymus serves as the central organ for maturing T lymphocytes; as a result, many mediastinal lymphomas are a malignancy of T lymphocytes.

The symptoms of mediastinal lymphoma tend to be fairly apparent, involving enlargement of the cranial mediastinal lymph nodes, thymus, or both. It can also cause swelling and abnormal growth of the head, neck, and front legs.

Dogs manifesting with this disease may have respiratory problems, such as difficulty breathing or coughing and swelling of the front legs or face. Increased thirst resulting in increased urination can also occur; if it does, hypercalcemia (life-threatening metabolic disorder) should be tested for as it seen in 40% of dogs with mediastinal lymphoma.

  • Extranodal Lymphoma. This is the rarest form of canine lymphoma. “Extranodal” refers to how it manifests in a location in the body other than in the lymph nodes. Organs typically affected by this type include eyes, kidneys, lungs, skin (cutaneous lymphoma), and central nervous system; other areas that can be invaded include the mammary tissue, liver, bones, and mouth.

Symptoms of extranodal lymphoma will vary greatly depending on which organ is impacted; for example, blindness can occur if the disease is in the eyes; renal failure if in the kidneys, seizures if in the central nervous system, bone fractures if in the bones, and respiratory issues if in the lungs.

The most common form of extranodal lymphoma is cutaneous (skin) lymphoma, which is categorized as either epitheliotropic (malignancy of T lymphocytes) or nonepitheliotropic (malignancy of B lymphocytes.) In the early stages, it usually presents as a skin rash with dry, red, itchy bumps or solitary or generalized scaly lesions and is fairly noticeable as the condition causes discomfort.

Because of this presentation, it is sometimes initially mistaken for allergies or fungal infections. As it becomes more severe, the skin will become redder, thickened, ulcerated, and might ooze fluids; large masses or tumors can develop. Cutaneous lymphoma can also affect the oral cavity causing ulcers, lesions, and nodules on the gums, lips, and roof of the mouth (sometimes mistaken at first as periodontal disease or gingivitis).


Within each of the four types described above, the disease can be categorized further into subtypes. There are more than 30 different histologic subtypes of canine lymphoma identified; some researchers theorize that there may be hundreds of subtypes, based on molecular analysis of markers, classifications, and subtypes of lymphocytes.

At the moment, further knowledge about the various subtypes would probably not result in significant changes in treatment protocols. In the future, targeted therapies for subtypes could lead to more effective treatments and improved prognosis.

The two primary and especially relevant subtypes are B-cell lymphoma and T-cell lymphoma. Approximately 60 to 80% of lymphoma cases are of the B-cell lymphoma subtype, which is a positive predictor; dogs with B-cell lymphoma tend to respond positively to treatment with a higher rate of complete remission, longer remission times, and increased survival times. T-cell lymphoma constitutes about 10 to 40% of lymphoma cases and has a negative predictive value based on not responding as well to treatment and for being at a higher risk for hypercalcemia.


Early detection and treatment are essential to ensuring the best possible outcome for lymphoma cases. Because dogs generally feel well and there are often only swollen lymph nodes (with no pain exhibited) as a symptom, catching the disease early can sometimes be quite difficult. As a result, the cancer can be quite advanced by the time a diagnosis is made. (Lymphoma is not the only the disease that creates swollen lymph nodes; this symptom does not guarantee your dog has lymphoma.)

Because multicentric lymphoma accounts for the majority of cases, an aspirate of an enlarged peripheral lymph node is usually sufficient to reach a presumptive diagnosis of the most common types of lymphomas.

Although diagnosis from cytology is fairly easily obtained, it does not differentiate the immunophenotype (B versus T lymphocyte). Histopathologic tissue evaluation (biopsy) is required in order to identify the type with the process of immunophenotyping.

Immunophenotyping is a molecular test usually performed by flow cytometry (a sophisticated laser technology that measures the amount of DNA in cancer cells) that classifies lymphomas by determining if the malignancy originates from B lymphocytes or T lymphocytes. Determining whether a lymphoma is B-cell or T-cell is invaluable as it provides the best predictive value; the adage “B is better, T is terrible” reflects this in its simplest form.

Diffuse large B-cell lymphoma (DLBCL) is the most common histologic subtype of lymphoma occurring in dogs. Most intermediate to high grade lymphomas are B-cell lymphomas – they tend to respond better and longer to chemotherapy than T-cell lymphomas; however, dogs with T-cell lymphoma have been known to go into remission for several months.

Another phenotyping test, the PCR antigen receptor rearrangement (PARR), can determine whether the cells are indicative of cancer or more consistent with a reactive process. For example, because the lymph nodes in the area of the jaw are reactive, the PARR test can help determine if cancer is present or if the dog just badly needs his teeth cleaned. The PARR test can also be used to detect minimal residual disease. Research is continuing to determine if this will be a useful clinical marker of early recurrence.

To ascertain the patient’s overall health, a complete physical exam will be performed; additional diagnostics often include a blood chemistry panel, urinalysis, x-rays, ultrasounds, and other forms of diagnostic imaging (these tests are also used for staging the disease).

In particular, it is important to screen for hypercalcemia. Hypercalcemia is a condition in which the hormone PTHrP (parathyroid hormone-related peptide) creates dangerous elevations in the blood calcium level. This well-documented syndrome is associated with lymphoma in dogs and is most often seen in T-cell lymphomas.

About 15% of dogs with lymphoma overall will have elevated blood calcium levels at diagnosis; this increases to 40% in dogs who have T-cell lymphoma. The condition causes additional clinical signs including increased thirst and urination, and, if left untreated, can cause serious damage to the kidneys and other organs and be life-threatening.

Unfortunately, due to the rapidly progressive nature of lymphoma, decisions regarding treatment need to be made as soon as possible after diagnosis. Unlike most other forms of cancer, lymphoma requires urgent care; without treatment, the median survival time is one month after diagnosis. Therefore, owners should be prepared to start treatment on the day of diagnosis, or within a day or two at most.


Once a diagnosis of lymphoma has been made, the stage (extent) of the lymphoid malignancy should be determined, and to assess this, several tests are recommended: lymph node aspirate, complete blood count, chemistry panel, urinalysis, phenotype, thoracic and chest radiographs, abdominal ultrasound, and a bone marrow aspirate.

Staging is prognostically significant; in general, the more extensive the spread, the higher the stage, the poorer the prognosis. However, even dogs with advanced disease can be successfully treated and experience remission. These tests also provide information about other conditions that may affect treatment or prognosis. The World Health Organization (WHO) five-tier staging system is the standard used to stage lymphoma in dogs:

  • Stage I: Single lymph node is involved.
  • Stage II: Multiple lymph nodes within in the same region are affected.
  • Stage III: Multiple lymph nodes in multiple regions involved.
  • Stage IV: Involvement of liver and/or spleen (in most cases lymph nodes are affected but it is possible that no lymph nodes are involved).
  • Stage V: Bone marrow or blood involvement, regardless of other areas affected and/or other organs other than liver, spleen and lymph nodes affected.

In addition, there are two categories of clinical substages. Dogs are categorized with substage A if clinical signs related to the disease are absent, and categorized as substage B if clinical signs related to the disease are present (systemic signs of illness).


Although canine lymphoma is a complex and challenging cancer, it is one of the most highly treatable cancers and most dogs respond to treatment. In fact, many dogs with lymphoma outlive animals with other diseases such as kidney, heart, and liver disease. While lymphoma is not curable, the goal with treatment is to quickly achieve remission for the longest period possible thus giving dogs and their owners more quality time together. It is essential that the type of lymphoma is identified as the type impacts treatment and prognosis. And because lymphoma is a very aggressive cancer, it is important to begin treatment as soon as possible.

Since lymphoma is a systemic disease that affects the whole body, the most effective treatment is also systemic in the form of chemotherapy, which provides many dogs with prolonged survival times and excellent quality of life, with little or no side effects.

The specific type of chemotherapy treatment used will vary based on the type of lymphoma. Other factors to consider when choosing a protocol are the disease-free interval, survival time, typical duration of remission, scheduling, and expense. Again, dogs with B-cell lymphoma tend to respond much more favorably to treatment than those with T-cell.

Because lymphoma is so common in dogs, there has been a substantial amount of research and testing of many different combinations of chemotherapy treatments. Multiagent chemotherapy protocols are considered the gold standard of treatment and have shown to provide the best response in terms of length of disease control and survival rates, as compared to single agent protocols.

The Madison Wisconsin Protocol, also known as UW-25 or CHOP, is a cocktail of drugs modeled after human lymphoma treatments and is widely considered to be the most effective treatment for intermediate- to high-grade canine lymphomas. This protocol utilizes three cytotoxic chemotherapy drugs – cyclophosphamide, doxorubicin (hydroxydaunrubicin), and vincristine (brand name Oncovin) – in combination with prednisone (CHOP). The prednisone is typically given daily at home as a tablet with the remainder of the protocol agents administered by an oncology specialist.

On average, 70 to 90% of dogs treated with CHOP experience partial or complete remission. For dogs with B-cell lymphomas, 80 to 90% can be expected to achieve remission within the first month. The median survival time is 12 months with 25% of patients still alive at two years. For T-cell lymphoma, about 70% will achieve remission with an average of six to eight months survival.

Other treatment options include the COP chemotherapy protocol (cyclophosphamide, Oncovin [vincristine], and prednisone), vincristine and Cytoxan; single-agent doxorubicin; and and lomustine/CCNU.  As a primary treatment, single-agent doxorubicin can result in a complete remission in up to 75% of patients with median survival time of up to eight months, though cumulative treatment with doxorubicin may result in cardiotoxicity, so the protocol may be contraindicated in any dog with evidence of or a history of pre-existing heart disease. Lomustine/CCNU is reported to be the most effective treatment for cutaneous lymphoma.


Remission is the condition in which the cancer has regressed. Partial remission means that the overall evidence of cancer has been reduced by at least 50%; complete remission indicates that the cancer has become undetectable to any readily available diagnostic screening (but it does not mean that the lymphoma has left the dog’s body, only that it has been treated into dormancy).

A dog in remission is essentially indistinguishable from a cancer-free dog. The lymph nodes will return to normal size and any illness related to the cancer usually resolves. Overall, there is approximately a 60 to 75% chance of achieving remission regardless of the protocol selected.

Studies show that the average time for a dog to be in remission the first time is eight to 10 months, including the period of chemotherapy administration. Remission status is continually monitored; for dogs with enlarged lymph nodes it typically involves checking the size of the lymph nodes. For dogs with other types of lymphoma, periodic imaging may be recommended. The Lymphoma Blood Test (LBT) from Avacta Animal Health can also be used monitor status since LBT levels can increase less than eight weeks before relapse.

Unfortunately, remission eventually relapses in most cases, but many dogs can restart chemotherapy with the hope of regaining remission status. At times, the same chemotherapy protocol may be used. For dogs successfully treated initially with the CHOP protocol, restarting CHOP at the time of the first relapse is typically recommended. About 90% of those treated with a second CHOP protocol will achieve another complete remission, however, the duration is usually shorter than the first time.

If a patient does not respond to the first CHOP protocol before completion or the treatment fails during the second protocol, the use of rescue protocols can be attempted; these consist of drugs that are not found in the standard chemotherapy protocols and kept in reserve for later use.

Commonly used rescue protocols include LAP (L-asparaginase, lomustine/CCNU, and prednisone) and MOPP (mechlorethamine, vincristine, procarbazine and prednisone). These are less likely to result in complete remission and some dogs will only achieve a partial remission, with an overall response rate of about 40 to 50%, and a median survival rate of 1.5 to 2.5 months.

Because cancer cells evolve over time, the disease can become resistant to certain drugs. Further treatments can be given, but it can become more difficult to achieve remission a second or third time and there does not appear to be any substantial effect on survival times.


Here are some compelling alternatives to consider in addition to the standard protocols described above:

  • Prednisone. This is usually a component of most lymphoma treatment protocols because it actually destroys lymphoma cells. It can even be administered as a standalone treatment. The average survival time without chemotherapy is about one month but treating with prednisone alone can increase this to about two to three months, with an average of 50% responding.
  • Tanovea-CA1 (rabacfosadine). This is a promising new advancement in treating canine lymphoma. This drug has been conditionally approved for use by the U.S. Food and Drug Administration (FDA), pending a full demonstration of its effectiveness (additional field studies are currently taking place to obtain full approval).
  • A Note About Prednisone

    Prednisone, a commonly used corticosteroid, is often used for its anti-inflammatory effects and anti-cancer-properties (it can kill malignant lymphoma cells). When prednisone is administered to a dog with lymphoma, cancer treatment has essentially begun. However, the administration of prednisone can complicate diagnosis, staging, and treatment of lymphoma. Therefore, it is strongly advised that prednisone not be administered until after diagnostics have been completed, results received, and a course of action decided upon.

    Specifically, prednisone can interfere with obtaining an accurate diagnosis from aspirate cytology, thus causing a delay in treatment. It can also affect the test for the lymphoma phenotype (subtypes B and T). Staging the cancer involves identifying how far the cancer has spread, provides information for treatment, provides a baseline for monitoring response, and allows for a more accurate prognosis. If prednisone has been started prior to staging, the data obtained may be influenced and inaccurate.

    Also, it has been found that dogs with lymphoma who have been pretreated with prednisone prior to chemotherapy don’t respond as well. In particular, it can trigger Multidrug Resistance (MDR), a mechanism that enables cancer cells to resist the chemotherapy drugs being administered to the dog (this can also occur during chemo treatment without prednisone as well); accordingly, dogs with MDR have a worse prognosis. Furthermore, it can cause resistance to other agents of chemotherapy so that it will be especially difficult to get a second remission after the first remission is lost.

    Bottom line: Wait to start prednisone.

Tanovea-CA1 is designed to target and destroy malignant lymphocytes and can be used not only to treat dogs that have never received any treatment but also those no longer responding to chemotherapy. It has demonstrated a 77% overall response and a 45% complete response rate. It is administered by veterinarians in five treatments every three weeks via intravenous infusion and is shown it to be generally well-tolerated.

  • Bone Marrow Transplant. One of the newest approaches to treating canine lymphoma is the bone marrow transplant – a form of stem cell therapy – modeled after a method used in human medicine. The process involves the dog receiving and completing CHOP therapy (which puts the cancer in remission); the harvesting and preservation of healthy stem cells from the patient; the administration of radiation to destroy any remaining cancer cells; and the returning of healthy cells to repopulate and restore blood cells.

In humans, the cure rate is about 40 to 60%; the procedure has been determined to be safe for use in dogs with cure rates of 33% for B-cell lymphomas and 15% for T-cell lymphomas. The process is expensive ($19,000 to $25,000) and requires about two weeks of hospitalization. Currently there are only two locations in the U.S. offering the procedure: the North Carolina State College of Veterinary Medicine (in Raleigh) and Bellingham (Washington) Veterinary Critical Care.

At some point lymphomas become resistant to treatment and no further remissions can be obtained. Eventually the uncontrolled cancer will infiltrate an organ (often the bone marrow or the liver) to such an extent that the organ fails. Under those circumstances, it is best to focus on high quality of life for the longest possible survival time.


Like most cancers, the eventual prognosis for dogs with lymphoma isn’t very uplifting. But it is a very treatable cancer, and dogs live well and longer with treatment. Several prognostic factors have been identified for estimating a dog’s response to treatment and survival time:

  • Dogs with signs of systemic illness (substage B) tend to have a worse prognosis than dogs with substage A.
  • Dogs with lymphoma histologically classified as being either intermediate- or high-grade tend to be highly responsive to chemotherapy, but early relapse is common with shorter survival times.
  • Dogs with lymphoma histologically classified as being low-grade have a lower response rate to systemic chemotherapy yet experience a positive survival length advantage when compared to intermediate- or high-grade tumors.
  • Dogs with T-cell lymphomas have a shorter survival time when compared with dogs with B-cell based malignancies.
  • Dogs with diffuse alimentary, central nervous system, or cutaneous lymphoma tend to have shorter survival times when compared to dogs with other anatomic forms of lymphoma.
  • Presence of hypercalcemia or anemia or a mediastinal mass are all associated with a poorer prognosis.
  • Intestinal lymphoma has a very poor prognosis.
  • Expectations for cases with Stage V lymphoma are much lower than those assigned to Stages I to IV.
  • Prolonged pre-treatment with corticosteroids is often a negative prognostic factor.
  • Ultimately, the estimates for survival times depend on the type of lymphoma combined with the stage and the treatment option selected (if any).
  • In the absence of treatment, most of the dogs diagnosed with lymphoma succumb to the disease in four to six weeks.
  • The median survival time with a multi-agent chemotherapy protocol is 13 to 14 months.
  • Traditional chemotherapy results in total remission in approximately 60 to 90% of cases with a median survival time of six to 12 months.
  • In about 20 to 25% cases, dogs live two years or longer after initiation of standard chemotherapy treatment.
  • Dogs treated with rescue protocols have a survival rate of 1.5 to 2.5 months.
  • Studies indicate that dogs who underwent splenectomy show a median survival rate of 14 months.
  • Complete cure is rare, but not unheard of. Bone marrow transplants show promise and potential for increased cure rates.

Above all, remember that prognoses are only guidelines based on average accumulative experiences. They are numbers, and as a dear friend and veterinary oncologist has said to me many times, “Treat the dog, not the numbers.”


  1. I am an oncology nurse. Your article is accurate and well written. However, you do not address the cost of these drugs. Humans who have insurance can still be financially devasted by their co-pays. You also do not address the intense side effects or quality of the dogs life while undergoin g treatment.

    • My Kirby had T cell Stage 3 Lymphoma. We used the CHOP therapy minus the doxorubicin. (very nasty) He lived 8 months. Total cost without insurance $15,000. At the beginning of treatment his health was very good. When we entered the sixth month his health began to decline. Organs began to not work as well. By the eight month we were battling kidney issues., hand feeding and extremely tired. We made the decision at this point to say goodbye, be cause we did not want him to suffer any further. We had just come back from vacation with him and he gave us all he had. I worked very closely with a holistic vet, and he was on many supplements. That is very important. I would never do chemotherapy again. I would look for more holistic treatments immediately and enjoy the time together..There are many new treatments available (stem cell, oxygen therapy, vit c therapy, and so on).

    • The best way is to google holistic veterinarians in your area. Cal all of them. If there is a large clinic in your area, call them. If you go to a dog park, ask people there. Groomers might know as well. Also trainers will know. I hope
      this helps.

  2. You do not address the more rare intestinal small cell lymphoma, which is more common in cats. My dog has it, and the treatment protocol is Prednisone and chlorambucil. Remissions can be obtained, and changes in diet can help with symptoms of digestive upset.
    It would be helpful if someone would look into this form of lymphoma.

  3. You did not mention what happens to dogs who have neither T or B cells. My dog fell into that category. She had null cells the rare firm that less than 3 to 5 percent of dogs get and very little is known about what to do.

  4. The author is incorrect in stating that a “histopathologic tissue evaluation (biopsy)” is the only way to do immunophenotyping of canine lymphoma. Flow cytometry is performed using living cells obtained from an enlarged lymph node via fine-needle aspirate (the same way cells are obtained for cytology) which are placed into a special transport medium and sent to the laboratory for testing. This is very important, as fine-needle as pirates may be done in the awake dog, while biopsy typically requires general anesthesia. Fine-needle aspiration is a less expensive and much easier test to perform than biopsy!! Similarly, the PARR test, if indicated, is also performed on fine-needle aspirate samples.

  5. Very thorough -thank you! My little guy fought multicentric lymphoma all of 2018… & while I learned all these things during that battle, believe many will find this in-depth article informative and very helpful, UP FRONT. Dog parents can know what to look for! Looking back, had found out my sweet boy had this disease for several months before it was identified & diagnosed as such. In part, because he was happy, energetic, playful and inquisitive. – definitely not sick! I was blind-sided. As for treatment, my little guy went through all these protocols, one by one, along with alternative and holistic therapies. I might add… as for alternative therapies, found their place in treatment protocol is still not recognized by many veterinarians… However, dog parents who are suiting up to battle this dreaded disease might just find them worthy of consideration, just as I did.

  6. Last spring my always healthy, 8 year old Chow mix became ill. She was thoroughly examined, and her vet ran every blood test available. The vet diagnosed uveitis, and started prednisone and antibiotics. She seemed to recover fully, but only for about two months. Same symptoms again, lack of appetite, labored breathing, lethargy. Back to vet for more blood tests, exam by two different vets, and full body x-rays. At no time did any of her lymph glands feel swollen. More steroids and antibiotics. After 10 days on the drugs she seemed to be getting worse. Luckily, my vet is open weekends. This time we could both feel multiple swollen glands. Vet took a biopsy and sent to lab. We were hopeful of treatment.
    But two mornings later, at around 5 am, I awoke to her having a massive seizure in her sleep. She never regained consciousness, and after another major seizure about 45 minutes later, she passed away on the floor next to my bed. Her vet was shocked she went so quickly. We received the lymphoma results from the lab two days later. J

    • First let me say how sorry I am about your wonderful Chow mix. It is extremely heartbreaking to lose our companions.
      My experience with Lymphoma for my 10 year old sweet Cavalier has been a roller coaster ride. In May of this year one morning one side of my dog’s face was swollen and then hour later, the swelling went down. Went to vet who noticed swollen lymph nodes on both sides of his neck and under the arm. A fine needle aspirate confirmed Lymphoma. Was put on Prednisone while I was deciding on chemo and 2 weeks later we went with it. All the while my dog was happy, eating, walking while he had chemo and Prednisone for the first month. Then in July things changed. He seemed to have aged 10 years, had on and off diarrhea from chemo and would sometimes hide. Yet he continued to eat, play and was actually gaining weight. On July 25 he developed facial paralysis on one side of face, which was awful. Oncologist didn’t know what caused this as he had never seen this before, so I ran around having his teeth checked for infection, thyroid tests and ear exam. In Aug. chemo wasn’t working so well and he was slowing down. He began to be afraid of going to oncologist and would stress out. He began having neurological problems and severe eye problems. Rescue protocol was tried at end of Aug. but didn’t have the results the oncologist would have liked and yet my dog continued to eat and play and walk. In Sept. was told I could try another protocol but it would be short lived and I should think of dog’s quality of life. Let him know in a week. Gave him low dose of Prednisone and Gabapentin to take. But oncologist had neurologist look at my dog on our final visit, and he said paralysis was due to disease progressing and he had COMS which affects the brain. whereby my beautiful boy would just freeze and not move and look scared
      And confused. A week later he was still waking me up every morning and would look ok but then a few hours later he would breathe heavy, then be fine, then pant really heavy and then the lymph nodes enlarged and returned making it hard for him to sleep at night as he struggled to breathe. Yet he continued to eat, gain weight and be happy to see company. He only lasted as long as it would have been if he was on Prednisone only and I wish I had gone that route because I believe the chemo brought all this out and while he was suffering, didn’t let it show because that is how dogs are. We decided to let him Go a few days later and I am still heartbroken with that because I didn’t want to do it. This stoic little dog went through 2 surgeries, had mitral valve disease and PSOM but was always a happy boy. He will be missed.

  7. My dog was diagnosed with lymphoma several years ago. We did chemo and she went into a strong remission which continues today. I think it is very important to note, however, that since then we have had her on a protocol of medicinal mushrooms (turkey tail, reishi, maitake and chaga) plus Chinese herbs. We are using Wei Qi Booster that boosts immunity and another herbal formula called Si Miao San. It is important, especially with the Chinese formulations, to have your dog see a knowledgeable holistic vet to monitor your pet but I think that the medicinal mushrooms are very safe to use. We use mushrooms from Mushroom Science because they are very pure. Also, the Chinese herbs and lots of other cancer support is available at Well Pet Dispensary online.

    • Dear Kim

      I would be grateful if I could get in touch with you. My dog has just been diagnosed with B cell Lymphoma (high grade) and I would like to explore the mix of holistic treatment and chemotherapy. I am heartened by your dog’s success in this and I would like to explore this. Thank you.

    • I would love to explore this route, my 6 year old boxer is being diagnosed as I speak. Please help! I can’t even begin to think about life without her.

    • What type of lymphoma did your dog have? My girl was just diagnosed with Cutaneous Epitheliotropic Lymphoma. T cell skin cancer. It is not anywhere else at the moment. I can’t find a holistic vet near me that has experience with this. My oncology appointment is Monday. I am not sure if she is familiar with holistic medicine. How and where did you find the information you got on what holistic things such as the mushrooms to give your dog? Any details would be most appreciated.
      Thank you

  8. I hope that Whole Dog Journal will do a follow up article on holistic and complimentary treatment for canine lymphoma and other cancers. It is challenging (and sometimes costly) but the information and the tools are out there so don’t give up! All in all, the natural remedies are very affordable compared to conventional treatments but of all cancers, it does seem as if lymphoma responds really well to chemo. There are also natural supplements you can use even during chemo. VCA Animal Hospitals seem to be getting more involved in the use and dissemination of info about natural additions to treatment. Sometimes it is also hard to know the right doses or combos of natural supplements, but again, the information is out there.

    • My oncologist at the VCA was not too versed in holistic treatments. Wanted to give my dog Liquid Gold but he felt it would be useless. Because I didn’t know if any of the holistic treatments would interfere with chemo, I was hesitant.. Asked about CBD oil and he said well it couldn’t hurt. Used it throughout short lived chemo. Asked about tumeric. He said he wasn’t familiar with it but later I did give it to my dog. My dog never went into remission and he is gone now but I wish my oncologist had been more knowledgeable.

  9. I am neither a vet nor a professional nutritionist but here is our story:
    My 12 year old English Setter was diagnosed with oral lymphoma in January 2019. Prognosis for his condition was 60 days, four months at the most. At that stage of his life, I chose not to do chemo. Instead I intensively researched holistic diets for dogs with cancer. I thus began creating home cooked meals for Merlin. This food was mixed with a premium dry kibble as I wanted to be sure he was getting adequate vitamins and minerals. Supplements were wild salmon oil in the morning, and K9 Power Show Stopper in the evening. To keep his mind active, we continued training in obedience. He earned his final CD leg in March!
    It is almost September and Merlin is still with us! Yes, he has declined and my guess is that sadly he does not have much time left. However, he still wakes up with a wagging tail and eating heartily! My extremely competent vet is amazed. Merlin is the first dog he has treated that has lived so long.
    Cooking for your dog does is not time consuming. A crockpot plus organic meats, vegetables and bone broth is all one needs. Yes, it added about $200 a month to my grocery bill but how can you put a price on the health and longevity of your best friend?!

  10. Our 4 &1/2 year old extremely active and healthy Collie recently passed on from Lymphoma. I was baffled by this article’s statement that it is good news if the diagnosis for a dog’s cancer is Lymphoma. Since the article goes on to state that the median length of life after treatment with (extremely expensive) chemotherapy is one year, how can this possibly be considered good news? I was pleased to see the success experienced by Deb Ashlock’s English Setter and found Kim McDonald’s recommendations for medicinal mushrooms and Chinese herbs encouraging. We were blindsided by the diagnosis.
    I will add that if introducing a holistic home cooked diet for your dog, the addition of a few Tablespoons oatmeal to each meal (1 C whole oats that have been processed in a food processor to a fine texture and then cooked with about 1&3/4 cups boiling water to a full boil, stirring ) can help to prevent diarrhea. The excess oatmeal can be refrigerated for later use.
    I am convinced that daily runs in a park that had been treated with pesticides ( even though we waited for about a month after treatment before using it) was a factor in our Collie’s illness.

    • Catherine
      I definitely agree that the pesticides in a park caused lymphoma in your dog. My dog used to love to roll on his back on the grass and did so many times over the 10 years. There would be an excessive amount of these blue pellets and all of us dog owners let our dogs play on the fields, because we didn’t know. It is amazing to me how many dogs in our neighborhood all passed from Cancer, Unfortunately, I would love to put the people who own the park on notice and have them be accountable, but as the fields belong to a very wealthy private academy here, I don’t think we have a prayer of that happening. I just don’t want other dogs to get Lymphoma like my dog. It was first evidenced as a small cyst on his back which grew to a cauliflower like mass but all the while our vet kept saying it was a cyst even while it was full blown for awhile and then in Nov. 2018 was removed and turned out to be a tumor. That probably was the beginning of the end for my dog because in Ma 2019 he was diagnosed with Lymphoma and passed in Sept. with complications from this disease.

  11. Our Trina was diagnosed with stage V lymphoma 6 months ago. She went through 19weeks of CHOP treatment. Initially was on prednisone but once we found the adverse effects and her not acting like herself consulted with a holistic dr at week 3. Has been in remission since week 4. Now eats not kibble but a balance homemade cooked meal- we freeze it for a week at a time.
    Along with cbd oil, a probiotic, vrs omega fish oil, yunan baiyao, six gentle pets, and mushroom kings—- she has been doing great for a pup w stage v lymphoma initially with thrombocytopenia… bleeding out of her rectum, vomiting, bruising, and blood in her eyes…
    With finishing the last treatment we are now told to be on a monthly oral
    Chemo pill.. and a small
    Dose of injectable chemo again… vincristine and chlorambucil… we do not want to continue chemo and are considering tumeric paste… but are hesitant because it’s hard to attribute whether it was the nutrition change, chemo, or both that have helped her…
    The longer between treatments she’s been off chemo… she acts like a puppy again… she’s a 7yr old pitbull…

  12. Hello
    Our 12.8 month lab Mickey had a tumor
    And diagnosed with lymphoma at age 9
    He went into remission until age 12.8
    When two inner ear infections and and abscess near his ear occurred. We treated these with Antibiotics and it took a solid month for him to recover. He also had some increase in kidney values.
    Because of the kidney issue I avoided any invasive procedures. We took him to an internist for the kidney issue. When the ear infection resolved a tumor grew on the ear that was infected. At the internist
    Appointment we had a sample of the ear tumor taken which was found to have lymphoma cells. Still I hesitated to treat him any further due to the kidney issue,
    And the fact that it took the ear so long to heal. Also his age was a factor. At that point he was acting fine, taking walks, eating well and having good life quality.

    The vet recommended seeing an oncologist immediately
    We went for a consult
    Immediately she was pushing chemo .As I questioned his recent health issues she just said it was not a problem

    My gut said different.

    She recommended prednisone and elapar for the tumor before actually starting chemo

    We agreed to that

    As soon as he started the prednisone
    He had diarrhea I called the oncologist
    Two days in a row with pa return call from her directly
    I stopped the prednisone as diarrhea is a severe side affect
    We had an appointment that week so when I went to that the oncologist was literally yelling at me for stopping the prednisone
    I told her I had to because of the diarrhea. She said that was from the lymphoma.

    Mickey was never sick
    Until all these drugs were started

    I should have walked out then but she
    Said we had little time left and he should have chemo
    We agreed thinking all these symptoms were from the lymphoma and wanted to help him
    2 days after the first chemo treatment
    Mickey couldn’t walk and wasn’t eating
    2 days after that he went into heart failure and we had to have him put to sleep

    Always follow your gut and comment sense
    I’ll always regret not walking out of that office that day

    • Carmela
      I agree. My post on Oct. 20 confirms that my dog developed all these terrible conditions due to chemo. Should have listened to my instincts and taken a chance on doing something else because in the end my dog suffered, more from the side effects of the chemo and lymphoma and the end result was the chemo stopped working and all the glands enlarged again.

  13. I first dealt with this disease in 1986. Woke up one morning and my female dobie had a larger pouch under her chin. Took her to the vet and it turned out to be lymphoma. We started chemo immediately. The doctor warned me that although she appeared to be a perfect specimen of her breed, she was infact dying. For the next 5 months she appeared healthy. Then one night she acted lethargic. The next day, without warning she went into convulsions. Shortly after she was dead. Now 34 years later, history repeats itself with my 8 year old boxer. Back in 86′ I had a sold support base. Now I’ve outlived my family. That boxer is all I’ve got.

  14. dear Keith so sorry to hear about your dear friend. I am looking after my lovely dog who is being treated homeopathically – it feels very touch and go but he’s still eating and enjoying a slow walk and a sniff about. i. hope it goes ok and that you’ll find a way through. there’s so many people out there – doggy and human who need you


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