Lymphoma Cancer in Dogs
What are lymphomas?
Lymphoma is a diverse group of cancers that originate in lymphocytes - a type of white blood cell in the immune system.
The commonly affected sites are lymph nodes, spleen and bone marrow, but lymphoma can occur in almost any tissue in
the body where there is lymph tissue such as the gastrointestinal tract, eyes, central nervous system, bone, testes,
bladder, heart, and nasal cavity. Lymphomas typically affect middle-aged dogs (6-9 years old), and certain breeds such as
boxers, bull mastiffs, basset hounds, Saint Bernards, Scottish terriers, Airedales, and bulldogs appear to be at higher risk.
Lymphoma can be classified into several categories:
How common are these tumors?
Lymphoma is one of the most common cancers in the dog. It accounts for approximately 7%-24% of all dog cancers and
83% of all hematopoietic (blood cell) cancers. The annual incidence is estimated at 1.5 cases per 100,000 dogs younger
than 1 year and 84 cases per 100,000 dogs 10-11 years old. Multicentric lymphoma (affecting many lymph nodes in the
body) is the most common type of lymphoma in the dog and accounts for approximately 80% of all lymphoma cases.
What are the symptoms?
The symptoms are variable and will depend on the cancer's location and how advanced it is. Commonly observed findings
are painless swollen lymph nodes, enlarged spleen and bone marrow involvement. The dogs may also show nonspecific
signs such as lack of appetite, weight loss, vomiting, diarrhea, shortness of breath, increased thirst, increased urination
and fever.
Dogs with gastrointestinal lymphoma can experience vomiting, diarrhea, weight loss, and lack of nutrient absorption. Dogs
with lymphoma in their chest cavity can have edema (swelling) of their neck, head or front limbs. Dogs with skin lymphoma
will show tumors that appear as nodules, plaques, ulcers or dermatitis (inflammation of the skin). Dogs with lymphoma in
their central nervous can experience seizures, paralysis, and partial loss of movement. Dogs with eye lymphoma show
infiltration and thickening of the iris, eye inflammation, blood in the eye, presence of puss, or glaucoma.
How is the diagnosis made?
Pets with suspected lymphoma will have a variety of tests done to confirm the diagnosis, including physical exam, blood
tests, urinalysis, imaging studies and biopsy. In many cases, fine-needle aspirates of the affected area is sufficient to
confirm lymphoma but biopsy remains as the gold standard for any cancer diagnosis. After confirming the diagnosis, it is
important to evaluate how advanced the disease in order to plan an appropriate treatment. More than 80% of dogs show
signs of advanced disease by the time of diagnosis so it is important to evaluate whether the bone marrow is involved (by
bone marrow aspirate or biopsy) and whether the disease has metastasized (spread) to other organs (by imaging
techniques such as ultrasound, X-rays, CT scan or MRI).
Do these tumors cause pain?
It is imperative that pets with cancer are provided with pain medication to relieve discomfort caused by the disease as well
as by the treatments. To learn more, please visit the Cancer Pain Management section.
What food should be fed to pets with cancer?
Pets with cancer need to be fed diets specifically designed to support a cancer patient. To learn more, please visit the
Cancer Nutrition section.
What are the treatment options?
Multicentric lymphomas
The treatment strategy for a dog with lymphoma will depend on the subtype, how advanced the cancer is and the overall
health of the pet. Chemotherapy remains as the treatment of choice, and combining several different chemotherapeutic
drugs has shown greater benefit compared to single drugs. The most effective chemotherapeutic drugs currently in use
include the combination of doxorubicin, L-asparaginase, polyethylene glycol-L-asparaginase, vincristine,
cyclophosphamide, and/or prednisone.
If multi-drug therapy cannot be used, single drug doxorubicin or prednisone can be offered as an alternative. For
doxorubicin, complete response is expected to be observed in 50-75% of dogs, with a median survival time of 6-8 months.
For prednisone, the response lasts 1-2 months but if pet owners decide to try chemotherapy after the prednisone, they
should be aware that the chemotherapy will be most likely be ineffective. Therefore, the earlier the pet owner chooses a
more aggressive multi-drug therapy, the better the chance of favorable outcome. In the rare cases where only one location
is affected by the cancer, it may be possible to treat it with surgery or radiation therapy rather than chemotherapy. The role
of radiation therapy for treating lymphoma in dogs is currently under investigation.
Non-multicentric lymphomas
There is not much information available for the treatment of non-multicentric lymphomas in dogs. If the cancer is localized
to a single site, surgery and/or radiation therapy are recommended and where the disease is present in multiple locations
of the body, chemotherapy is the treatment of choice.
Are there any clinical trials investigating new treatments?
There are only a few available clinical trials investigating new treatments for lymphoma in pets. To learn more about clinical
trials open to enrollment in the United States, please visit the Clinical Trials for Lymphoma section. To learn more about
veterinary clinical trials in general, please visit the Pet Clinical Trials section.
To help Pet Cancer Center conduct more lymphoma trials across the United States in order to make novel and more
efficacious therapies available to pets, please
What is the prognosis?
The prognosis for dogs with lymphoma will depend on the lymphoma subtype, location of the disease, how advanced it is
and the overall health. Generally speaking, the earlier the diagnosis is made, the better Without treatment, most dogs will
die of the disease in 4-6 weeks. Fortunately, a high percentage of dogs have a good response to chemotherapy without
major side effects. Dogs that respond to chemotherapy and achieve complete remission (absence of disease) usually
remain free of symptoms and return to a very good quality of life. About 25% of dogs are long term survivors (longer than 2
years) and some are cured.
Additional online resources about lymphoma in pets:
www.caninecancerawareness.org/html/CanineCancerLymphoma.html
www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/10500.htm
www.veterinarypartner.com/Content.plx?P=A&A=575
www.marvistavet.com/html/canine_lymphoma.html
www.vetmed.wsu.edu/clientED/lsa.asp
www.vrcc.com/library/disease_k9_lymphoma.shtml
www.lymphomainfo.net/lymphoma/animal.html
www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2005&PID=10916&O=Generic
www.vetspecialists.co.uk/06_Animal_Welfare/Oncology_Facts/Canine_Lymphoma.html
www.dogcancer.net/lymph.html
Sources:
Lymphoma is a diverse group of cancers that originate in lymphocytes - a type of white blood cell in the immune system.
The commonly affected sites are lymph nodes, spleen and bone marrow, but lymphoma can occur in almost any tissue in
the body where there is lymph tissue such as the gastrointestinal tract, eyes, central nervous system, bone, testes,
bladder, heart, and nasal cavity. Lymphomas typically affect middle-aged dogs (6-9 years old), and certain breeds such as
boxers, bull mastiffs, basset hounds, Saint Bernards, Scottish terriers, Airedales, and bulldogs appear to be at higher risk.
Lymphoma can be classified into several categories:
- Multicentric lymphoma
- Mediastinal lymphoma
- Alimentary/intestinal lymphoma
- Cutaneous (skin) lymphoma
- Extranodal lymphoma
How common are these tumors?
Lymphoma is one of the most common cancers in the dog. It accounts for approximately 7%-24% of all dog cancers and
83% of all hematopoietic (blood cell) cancers. The annual incidence is estimated at 1.5 cases per 100,000 dogs younger
than 1 year and 84 cases per 100,000 dogs 10-11 years old. Multicentric lymphoma (affecting many lymph nodes in the
body) is the most common type of lymphoma in the dog and accounts for approximately 80% of all lymphoma cases.
What are the symptoms?
The symptoms are variable and will depend on the cancer's location and how advanced it is. Commonly observed findings
are painless swollen lymph nodes, enlarged spleen and bone marrow involvement. The dogs may also show nonspecific
signs such as lack of appetite, weight loss, vomiting, diarrhea, shortness of breath, increased thirst, increased urination
and fever.
Dogs with gastrointestinal lymphoma can experience vomiting, diarrhea, weight loss, and lack of nutrient absorption. Dogs
with lymphoma in their chest cavity can have edema (swelling) of their neck, head or front limbs. Dogs with skin lymphoma
will show tumors that appear as nodules, plaques, ulcers or dermatitis (inflammation of the skin). Dogs with lymphoma in
their central nervous can experience seizures, paralysis, and partial loss of movement. Dogs with eye lymphoma show
infiltration and thickening of the iris, eye inflammation, blood in the eye, presence of puss, or glaucoma.
How is the diagnosis made?
Pets with suspected lymphoma will have a variety of tests done to confirm the diagnosis, including physical exam, blood
tests, urinalysis, imaging studies and biopsy. In many cases, fine-needle aspirates of the affected area is sufficient to
confirm lymphoma but biopsy remains as the gold standard for any cancer diagnosis. After confirming the diagnosis, it is
important to evaluate how advanced the disease in order to plan an appropriate treatment. More than 80% of dogs show
signs of advanced disease by the time of diagnosis so it is important to evaluate whether the bone marrow is involved (by
bone marrow aspirate or biopsy) and whether the disease has metastasized (spread) to other organs (by imaging
techniques such as ultrasound, X-rays, CT scan or MRI).
Do these tumors cause pain?
It is imperative that pets with cancer are provided with pain medication to relieve discomfort caused by the disease as well
as by the treatments. To learn more, please visit the Cancer Pain Management section.
What food should be fed to pets with cancer?
Pets with cancer need to be fed diets specifically designed to support a cancer patient. To learn more, please visit the
Cancer Nutrition section.
What are the treatment options?
Multicentric lymphomas
The treatment strategy for a dog with lymphoma will depend on the subtype, how advanced the cancer is and the overall
health of the pet. Chemotherapy remains as the treatment of choice, and combining several different chemotherapeutic
drugs has shown greater benefit compared to single drugs. The most effective chemotherapeutic drugs currently in use
include the combination of doxorubicin, L-asparaginase, polyethylene glycol-L-asparaginase, vincristine,
cyclophosphamide, and/or prednisone.
If multi-drug therapy cannot be used, single drug doxorubicin or prednisone can be offered as an alternative. For
doxorubicin, complete response is expected to be observed in 50-75% of dogs, with a median survival time of 6-8 months.
For prednisone, the response lasts 1-2 months but if pet owners decide to try chemotherapy after the prednisone, they
should be aware that the chemotherapy will be most likely be ineffective. Therefore, the earlier the pet owner chooses a
more aggressive multi-drug therapy, the better the chance of favorable outcome. In the rare cases where only one location
is affected by the cancer, it may be possible to treat it with surgery or radiation therapy rather than chemotherapy. The role
of radiation therapy for treating lymphoma in dogs is currently under investigation.
Non-multicentric lymphomas
There is not much information available for the treatment of non-multicentric lymphomas in dogs. If the cancer is localized
to a single site, surgery and/or radiation therapy are recommended and where the disease is present in multiple locations
of the body, chemotherapy is the treatment of choice.
Are there any clinical trials investigating new treatments?
There are only a few available clinical trials investigating new treatments for lymphoma in pets. To learn more about clinical
trials open to enrollment in the United States, please visit the Clinical Trials for Lymphoma section. To learn more about
veterinary clinical trials in general, please visit the Pet Clinical Trials section.
To help Pet Cancer Center conduct more lymphoma trials across the United States in order to make novel and more
efficacious therapies available to pets, please
What is the prognosis?
The prognosis for dogs with lymphoma will depend on the lymphoma subtype, location of the disease, how advanced it is
and the overall health. Generally speaking, the earlier the diagnosis is made, the better Without treatment, most dogs will
die of the disease in 4-6 weeks. Fortunately, a high percentage of dogs have a good response to chemotherapy without
major side effects. Dogs that respond to chemotherapy and achieve complete remission (absence of disease) usually
remain free of symptoms and return to a very good quality of life. About 25% of dogs are long term survivors (longer than 2
years) and some are cured.
Additional online resources about lymphoma in pets:
www.caninecancerawareness.org/html/CanineCancerLymphoma.html
www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/10500.htm
www.veterinarypartner.com/Content.plx?P=A&A=575
www.marvistavet.com/html/canine_lymphoma.html
www.vetmed.wsu.edu/clientED/lsa.asp
www.vrcc.com/library/disease_k9_lymphoma.shtml
www.lymphomainfo.net/lymphoma/animal.html
www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2005&PID=10916&O=Generic
www.vetspecialists.co.uk/06_Animal_Welfare/Oncology_Facts/Canine_Lymphoma.html
www.dogcancer.net/lymph.html
Sources:
- Withrow Stephen J, and David M. Vail. Small Animal Clinical Oncology. St Louis: Saunders Elsevier, 2007.
- Morrison Wallace B. Cancer in Dogs and Cats: Medical and Surgical Management. Baltimore: Williams&Wilkins, 1998.
© 2007 Pet Cancer Center. ALL RIGHTS RESERVED.
Last updated 6/7/09
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