Last Updated: 23/02/2026
Lymphoma in Dogs: Causes, Signs, Diagnosis & Treatment
As one of the most common cancers in dogs, a lymphoma diagnosis can be overwhelming. Discover the key symptoms to watch for, how Australian vets diagnose different types, and the latest chemotherapy protocols designed to improve your pet's quality of life.
Author: Dr Nicole du Plessis BVSc (Hons)
Reading Time: 13 minutes - short read
Finding a lump while giving your dog a belly rub or noticing they are just "off" their food can be a worrying experience for any pet parent. While lymphoma is a serious diagnosis, it is also one of the most responsive cancers to treatment in the veterinary world.
Understanding the different types of this disease - from those affecting the lymph nodes to the "great imitator" on the skin - is the first step in making the best decisions for your furry family member. This guide breaks down the science into actionable steps so you can focus on what matters most: more quality time together.
What is lymphoma in dogs?
Lymphoma is a group of diverse cancers with more than 30 different types of lymphoma described in dogs.
It arises from a type of white blood cell called lymphocytes, which when healthy are involved in vital immune functions.
Canine lymphoma can affect almost every part of the body, but frequently affect the lymphoreticular system. This includes lymph nodes, lymphatic vessels, bone marrow, the thymus and the spleen.
What causes lymphoma in dogs?
Despite lymphoma being one of the most common cancers in dogs, the cause remains unlear.
Over the years, many risk-factors have been studied:
- The use of lawn care herbicides such as 2,4-dichlorophenoxyacetic acid have been examined, with a potential increased risk with exposure
- Dogs who live in areas with high levels of electromagnetic fields have been examined with a weak to moderate risk identified, especially for dogs that spend the majority of their time outdoors.
- Certain bacteria, viruses, and skin conditions such as atopic dermatitis
Unfortunately, no direct cause has been linked to the development of this diverse group of cancers and it is most likely multifactorial.
As canine lymohoma shares similarities with Non-Hodgkins Lymphoma in humans, immune suppression has been proposed as a risk factor of developing lymphoma. This is extrapolated from human studies, where lymphoma patients have significantly suppressed immune function. Definitive evidence that immune suppression causes canine lymphoma has not been confirmed.
Common dog breeds predisposed to lymphoma
Many popular breeds have a genetic predisposition for developing lymphoma. These include:
- Dobermann
- Rottweiler: Rottweilers have a high prevalence of B-cell lymphomas
- Australian Cattle Dog
- Boxer: Boxers tend to develop T-cell lymphomas (either high- or low-grade)
- Bernese Mountain Dogs
Higher incidence of lymphoma are found typically in breeds such as:
- Bullmastiffs
- Basset hounds
- St. Bernards
- Scottish terriers
- Airedales
- Pitbulls
- Briards
- Irish setters
- German Shepherds
- Labradors
- Bulldogs
Recognising the symptoms of lymphoma in dogs
Lymphoma can be difficult to detect, especially in the earlier stages of the disease. As it can affect many different body systems, it has many different presentations. Some signs of lymphoma are very subtle or non-specific. There are several different types of lymohoma in dogs:
Generalised or multicentric lymphoma
This form of lymphoma will often present with enlarged peripheral lymphnodes at various sites;
- Submandibular lymph node found under the jaw
- Prescapular lymphnode in front of the shoulder blades
- Popliteal lymph node behind the knees
Most dogs will be seemingly healthy, unless they fall into the 10-20% of dogs who have substage b (see staging for lymphoma). Other symptoms that may be present include:
- Reduced appetite
- Weight-loss
- Lethargy
- Occasionally an increased thirst and urination
Alimentary or gastrointestinal lymphoma
This form of lymphoma relates to the gastrointestinal tract. It can present with relatively non-specific signs such as:
- Vomiting
- Diarrhoea
- Weight-loss
- Reduced appetite
Cutaneous lymphoma
The 'great imitator' of lymphoma. This form of lymphoma can have a wide variety of lesions, from skin to oral. It may or may not cause itching for the dog and can vary from a peculiar-appearing rash to large nodular tumours.
Mediastinal lymphoma
Relating to the thorax, this form of lymphoma tends to present with respiratory signs. These signs can be overt, such as difficulty breathing, or muffled heart sounds that can be detected during a chest examination.
Signs of lymphoma that may be noticed at home
- Enlarged lymph nodes: The most common sign of lymphoma in dogs is the presence of swollen lymph nodes, which can often be felt as lumps under the skin, particularly around the neck, shoulders, groin, and behind the knees.
- Increased thirst and urination:Certain types of lymphoma produce a hormone called PTH-rp (parathyroid hormone related protein) leading to hypercalcaemia, too much calcium in the blood stream. This can lead to drinking more water than usual and needing to urinate more frequently.
- Gastrointestinal symptoms:Lymphoma can also affect the digestive tract, leading to symptoms such as vomiting, diarrhoea, or abdominal pain.
- Loss of appetite:Dogs with lymphoma may experience a decrease in appetite or may refuse to eat altogether. This can lead to weight loss and a decrease in energy levels.
- Lethargy: Dogs with lymphoma may appear tired or lethargic, showing a lack of interest in activities they previously enjoyed.
- Difficulty breathing: In some cases, lymphoma can affect the lungs, causing difficulty breathing or coughing.
- Skin changes: In rare cases, lymphoma may manifest as lumps or lesions on the skin.
- Ocular signs: Occasionally lymphoma can cause uveitis which may make the white part of the eye look red, and the eye appear cloudy.
- Fever: Dogs with lymphoma may develop a fever, although this symptom is not always present.
How do vets diagnose canine lymphoma?
The mere discussion of lymphoma can come to a shock to owners, especially if the dog was brought to the vet for a completely unrelated reason. Although canine lymphoma may be suspected during a physical examination, there are a number of diagnostic steps prior to being able to definitively diagnose lymphoma.
The first 2 steps below help your veterinarian reach the diagnosis of canine lymphoma. Other questions still remain that can alter prognosis and treatment. This is where staging becomes important, to determine how far has the cancer spread? To answer this, the additional steps (diagnostic tests and imaging) are required. This can also help establish a baseline for monitoring response to treatment, if that is the direction chosen for the dog.
Chemotherapy and treatment options for dogs
The main treatment for most types of lymphoma is chemotherapy.
Chemotherapy
- How it works: Attacks uncontrolled, rapidly multiplying cancer cells. Unfortunately healthy rapidly dividing cells will also be affected. Side effects are often related to the bone marrow, hair follicles, and gastrointestinal tract, where normal rapidly dividing cells are found.
- Goal: To improve quality of life, not necessarily eliminate the cancer altogether as in humans.
- Side effects: Since the objective is different in pets compared to humans, chemotherapy is often less aggressive in pets, so generally fewer side effects are seen.
There are a wide range of chemotherapy drugs and applications in veterinary medicine. The most appropriate treatment protocol can depend on the type of cancer involved.
Survival rates and life expectancy with lymphoma
Multicentric lymphoma in dogs is a cancer that has good response rates to chemotherapy. The goal of treatment is complete remission, which eliminates the symptoms of lymphoma, while also preserving a good quality of life for the dog. Canine lymphoma treatment can achieve complete remission rates up to 95%; however, this will only be temporary. Unfortunately, lymphoma will return despite chemotherapy. Treatment can be administered again, but generally remission will be shorter the second time around.
- B-cell lymphoma: Dogs who have undergone multi-agent chemotherapy usually live an average of 12 months. This reduces to 25% of dogs surviving past 24 months.
- T-cell lymphoma: Dogs who have undergone multi-agent chemotherapy for T-cell lymohoma usually live an average of 6 to 8 months.
Some dogs will go on to live far longer than the average and some will sadly pass away sooner than the average survival time. A number of factors can affect this such as the overall health of the dog, and the presence of any other co-morbidities such as heart disease or kidney disease.
Chemotherapy is the main treatment for canine lymmphoma. Other medications can be used to help keep the dog comfortable for a short time. Prednisone alone may extend survival time for 2 to 3 months. Without any intervention lymphoma moves quickly, sadly most dogs will not live past 1 month after diagnosis.
FAQs
A lymphoma diagnosis is undoubtedly tough, but with modern veterinary medicine, there are many ways to manage the disease and maintain a joyful quality of life. Whether you choose a comprehensive chemotherapy protocol or palliative care to keep them comfortable, the goal is always to support your dog’s wellbeing. Every extra wag and happy walk is a win, and your veterinary team is there to walk this path with you every step of the way.
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History
Our experts continually monitor the health and wellness space and we update our articles when new information becomes available.
Thu 19 Feb 2026
Edited by Dr Gillian Hill BVSc (Hons)Dr Nicole du Plessis BVSc (Hons)
Author, BVSc (Hons)
Dr. Nicole du Plessis is one of Pet Circle's qualified veterinarians and passionate pet care enthusiasts. Dr. Nicole graduated from the University of Queensland in 2016 with a Bachelor of Veterinary Science and worked for a number of years in small animal clinics across South East Queensland before joining the Pet Circle team. Over the years, Nicole has developed special interests in preventative medicine, infectious diseases, small animal medicine and ultrasound.
