By Courtney Prue | June 18, 2025

Lymphoma in Dogs: Causes, Symptoms & Treatment

What is lymphoma in dogs?

Lymphoma is a type of cancer that affects the lymphocytes, which are white blood cells that play a vital role in the immune system. When an animal develops lymphoma healthy lymphocytes circulate throughout the body as well as their malignant (cancerous) counterparts. This means that although lymphoma may be diagnosed in a single location or lump, it can affect any part of the body. It most commonly affects lymph nodes, spleen, liver, thymus and bone marrow, and spread to the gastrointestinal tract, brain and body cavities is also common. Early detection and treatment can help manage the lymphoma symptoms in dogs and improve quality of life.

What causes lymphoma in dogs?

Unfortunately, the exact cause of lymphoma in dogs is unknown. However, some related factors include:

Age: Most dogs diagnosed with lymphoma are middle–aged or older, however, young dogs can still be affected

Breed: Dogs of any breed can get lymphoma, but it is particularly common in Golden Retrievers, Basset Hounds, Mastiffs, Boxers and Scottish terriers. 

Environmental: Exposure to certain environmental factors, such as pesticides and herbicides as well as magnetic fields, may increase the risk of developing lymphoma.

What are the first signs of lymphoma in dogs?

The lymphoma symptoms in dogs can vary depending on the location and extent of the cancer. They can also be very vague and often mimic other common diseases.

Early signs include:

• Swollen lymph nodes noted externally (one or more under the jaw, behind knees, in front of shoulders)
• There are usually no other signs of illness during these early stages, but they may have vague signs such as weakness, less energy, weight loss

More advanced signs include:

• Inappetance
• Severe lethargy
• Drastic weight loss
• Vomiting and/or diarrhoea
• Increased urination and drinking
• Swollen abdomen 
• Pale gums 
• Increased bruising
• Increased breathing sounds and effort, including snoring 

If you notice any of these symptoms in your dog, it’s important to take them to a veterinarian for diagnosis. Don’t hesitate to call your veterinarian, our team or an emergency veterinary clinic for guidance on how to proceed.

How is lymphoma diagnosed in dogs?

• Tissue testing. The first sign noted by an owner or their vet is usually a lump that turns out to be an enlarged lymph node. This enlarged tissue can be tested either via fine needle aspirate, where a needle is inserted and a small amount of cells are examined under the microscope, or via biopsy where a segment of the swelling is cut out and examined. A similar test can also be performed on cells or tissue taken from the abdomen or other locations if needed. 
• Blood tests. This helps assess any systemic impacts of the disease, and other underlying illness and assess for eligibility for any treatments
• Chest radiographs. This might be recommended to examine the lymph nodes in the chest and to look for other causes for the symptoms noted. 
• Abdominal ultrasound. This allows for examination of the organs and intestines in the abdomen, looking for any abnormal growths and or fluid accumulation..
• Advanced imaging such as CT or MRI may be recommended if needed. These are only available at certain clinics or specialist hospitals.

Can my lymphoma dog decline suddenly?

It is important to know the symptoms that indicate a medical emergency in dogs with lymphoma as this disease can progress very rapidly and prompt veterinary attention can be life-saving. Here are some symptoms to watch out for:

• Difficulty breathing: This can manifest as constant panting despite a mild day, very rapid shallow breathing, difficulty settling or falling asleep, with constant shifting positions while panting. End–stage lymphoma commonly impacts a dog‘s breathing and this is a very serious form of suffering. 
• Pale gums: This can be a sign of poor oxygenation or very low red blood cell count and should be evaluated by a veterinarian immediately.
• Weakness or collapse: This may indicate poor blood flow to vital organs and requires immediate veterinary attention.
• Loss of consciousness: This can occur suddenly and may be a sign of cardiac arrest, which requires immediate cardiopulmonary resuscitation (CPR).
• Seizures: This involves either full body or focal muscle spasms usually with loss of consciousness. 

If you observe any of these symptoms, seeking immediate veterinary attention is important. Time is critical in emergencies, and a delay in treatment can have serious consequences for your dog’s health. 

Is lymphoma in dogs treatable? 

There are several treatment options available that can help manage the lymphoma symptoms in dogs and improve your dog’s quality of life. The most common treatment for lymphoma in dogs is chemotherapy. There are a variety of protocols that are tailored by an oncologist for each patient. Chemotherapy can be given orally or intravenously, and it works by killing cancer cells and shrinking tumours. 

However, chemotherapy is not always possible or appropriate. Always discuss this with your veterinarian or veterinary oncologist.

Other medications and treatments can be used to manage the lymphoma symptoms in dogs. These include:

•   Steroids such as prednisolone
•   Appetite stimulants
•   Pain medications
•   Fluid therapy

The medical management of lymphoma can be confusing and overwhelming. Get in touch with our team today for a personalised discussion. 

What can I do at home to help my dog with lymphoma?

In addition to medical treatment, there are several things you can do at home to help your dog manage their symptoms and improve their quality of life. These include:

•   Providing a comfortable and quiet place for them to rest
•   Encouraging your dog to eat by offering high-quality, delicious food
•   Keeping them hydrated by offering plenty of fresh water, or mixing water with their food
•   Giving them plenty of love and attention
•   Minimising stressors in the environment
•   Administering medication as prescribed by your veterinarian

How long do dogs live after a lymphoma diagnosis?

The prognosis for dogs with lymphoma varies depending on the type and stage of the disease, as well as their response to treatment. Without treatment, the median survival time is approximately 4 – 6 weeks. Survival time with chemotherapy depends on many factors and the median survival time is between 6 – 12 months. 

For more clarity, ask your veterinarian or oncologist to explain the type and stage of your dog‘s lymphoma. They may need to perform further testing to provide this information. 

End-of-life care tips

If your beloved dog‘s lymphoma has progressed to a point where treatment is no longer effective,  it’s important to consider end-of-life care options, including possibly putting your dog to sleep (euthanasia). This can be an overwhelming and distressing thing to even think about. Rest Your Paws is here to support you and provide compassionate care for your beloved pet throughout their journey.

Here are some end-of-life care tips for your dog:

• Keep them hydrated and well-nourished with some delicious food
• Spend quality time with them, making the most of every moment, such as with a bucket list.
• Offer a calm and peaceful environment, free from stressors that can exacerbate symptoms
• Administer medications as prescribed, including for pain management and symptom relief
• Provide a warm and comfortable space for your dog to rest and sleep, with easy access to food, water, and toilet facilities
• Monitor your dog’s breathing, and overall condition, and seek veterinary attention if necessary
• Evaluate their pain regularly and work with your veterinarian or our team to reduce pain.
• Evaluate their quality of life regularly, or reach out to a palliative care vet to help you with this. 
• Consult our End of Life Care Pack to get prepared to put your dog to sleep.
• Track good days and bad days on our Quality of Life Assessment Calendar.

Please know that we are here to support you every step of the way. We understand that this is a challenging time for you and your family, and we are committed to providing you with the guidance and care that you and your furry friend deserve. If you want to learn more about putting your pet to sleep, dog euthanasia at home, options to put your pet down at home, costs of euthanasia at home or what it looks like to put your pet to sleep at home, call us on 0422 157 675 or visit our website.

Lymphoma in dogs is a serious and potentially life-threatening disease. At Rest Your Paws, we understand that a diagnosis of lymphoma in your companion can be overwhelming. However, with the right information and support, you can provide your pet with the best possible care throughout its journey. With appropriate treatment and management, dogs with lymphoma can achieve a good quality of life for as long as possible. Remember to always consult with your veterinarian to ensure that your dog receives the appropriate treatment and care for their specific case of lymphoma.  Please do not hesitate to reach out to us if you have any questions or concerns – we are here to help.

Rest Your Paws

We offer in-home pet euthanasia for dogs, cats and other pets. Say goodbye with peace and dignity to your beloved pet. Professional and experienced end-of-life support.