What is lymphoma?
Lymphoma is one of the most common cancers in dogs. It is a cancer of lymphocytes, a type of white blood cell that plays an important role in the immune system. Because these cells travel throughout the body, lymphoma is usually considered a systemic disease. This means it often affects more than one area of the body at a time rather than staying in one place.
What are the signs of lymphoma in dogs?
Lymphoma may start quietly. Early on, some dogs show very few signs—or none at all—while others develop noticeable changes sooner. Symptoms will depend on which areas of the body are affected.
For many dogs, the first sign is painless swelling of the lymph nodes. They may feel like lumps under the jaw or behind the knees. As the disease progresses, you may start to see more general signs like weight loss or less interest in food.
Symptoms of lymphoma in dogs may include:
- Swollen lymph nodes (the most common sign): You may feel your dog’s lymph nodes under their chin, in front of their shoulders, in their armpits or groin, or behind their knees. Lymph nodes can be difficult to feel unless they are enlarged.
- Unexplained weight loss
- Low energy or reduced interest in play
- Vomiting or diarrhea
- Increased thirst or urination
- Decreased appetite
- Shortness of breath
Contact your veterinarian if you notice new swelling, concerning appetite changes, or behavior shifts—even if your dog otherwise seems well.
What causes lymphoma in dogs?
There is no known single, clear cause for lymphoma. The risk of a dog getting this cancer can be influenced by:
- Age: Middle-aged to older dogs (7+ years) have an increased risk. As dogs age, their cells have had more time to build up genetic damage, and their bodies may not be as good at stopping abnormal cells from growing.
- Breed: Certain breeds are diagnosed with lymphoma more often than others, suggesting genetics may play a role.
Lymphoma is not caused by poor care, diet choices, missed prevention, or something a pet parent did or didn’t do. It’s a disease that can develop despite doing everything right.
Are there different types of lymphoma that dogs can get?
There are different types of lymphoma in dogs. Hearing the language your veterinarian may use to describe them can feel overwhelming. But, these terms simply describe:
Where lymphoma appears:
Lymphoma can affect different parts of the body, which often explains why symptoms vary from dog to dog:
- Multicentric: The most common form. Multiple lymph nodes throughout the body are affected and can become enlarged.
- Gastrointestinal or Alimentary: Affects the digestive tract (stomach and intestines) and may cause vomiting, diarrhea, or unexplained weight loss.
- Cutaneous: Involves the skin (often around the eyes and lips, but can be seen anywhere on the body) and may look like redness, sores, scaly patches, itching, or thickened skin.
- Mediastinal: Occurs in the chest and can cause breathing changes due to pressure on the lungs or heart.
- Extranodal: Develops outside the lymph nodes, such as in the eyes, kidneys, lungs, or brain. Symptoms depend on which organ or organs are affected.
The type of lymphocyte:
- B-cell: More common and often responds better to treatment
- T-cell: Less common and may behave more aggressively
How quickly it tends to progress:
- Indolent (low grade): Grows slowly and may not require immediate treatment.
- Aggressive (high grade): Most common and progresses more quickly but often responds well to chemotherapy.
These distinctions help explain why lymphoma can look very different from one dog to another—and why treatment plans are individualized. The majority of lymphoma in dogs is multicentric, high grade, B-cell lymphoma.
Having a common language is helpful when speaking with your vet, and they can walk you through what these types mean for your dog.
How does a veterinarian diagnose lymphoma?
In many cases, lymphoma can be diagnosed quickly, and with minimal discomfort for your dog.
Veterinarians may identify lymphoma in one of two ways:
- Cancer screening at a routine wellness checkup when your dog seems healthy
- Diagnostic testing once symptoms are present and they are concerned about lymphoma
Cancer screening when your dog seems healthy
For dogs aged seven and older or breeds at higher risk, veterinarians may recommend screening during routine wellness checkups. This involves a simple blood test, which can detect lymphoma signal early, before a dog is showing signs from the outside. While screening doesn’t diagnose lymphoma on its own, it can help your veterinarian understand when closer evaluation is needed.
Diagnosing lymphoma once signs are present
If your dog is showing symptoms, veterinarians use diagnostic tests to confirm whether lymphoma is present and understand how widespread it may be.
Depending on what your vet finds during the exam, further testing may include:
- Fine-needle aspirate and cytology: A small needle collects cells from a lymph node or other area of concern. This is one of the most common ways to diagnose lymphoma.
- Biopsy and histopathology: In some cases, a small tissue sample is surgically removed and examined by a pathologist. This diagnostic test is less commonly needed but may be helpful in certain situations.
- Blood tests: Blood work helps evaluate overall health and organ function.
- Imaging (X-rays or ultrasound): Imaging helps assess the internal organs or areas that can’t be felt on a physical exam. It can also help determine how widespread the disease may be.
- Additional tests: Specialized tests may be used to further classify the lymphoma, which can help guide treatment and provide information on prognosis.
Diagnosis allows veterinarians to:
- Confirm whether lymphoma is present and what type it is, guiding prognosis and treatment conversations
- Understand how widespread the disease is
- Create a care plan focused on comfort, quality of life, and treatment goals
Earlier diagnosis may give families more choices and time to make informed decisions.
What are the stages of lymphoma?
When a dog is diagnosed, veterinarians use staging to help guide next steps and treatment decisions. Staging offers insight into what to expect—but it doesn’t predict how any one dog will feel or respond to treatment.
Stages: How far lymphoma has spread
- Stage I: One lymph node affected
- Stage II: Multiple lymph nodes in one area
- Stage III: Lymph nodes throughout the body affected
- Stage IV: Liver and/or spleen affected
- Stage V: Bone marrow or other organs affected
Substages: How your dog is feeling
- Substage A: No noticeable symptoms
- Substage B: Feeling unwell, which may include low energy, appetite loss, or weight loss
Dogs at the same stage can have very different energy levels and comfort, so stage can’t be determined by how a dog looks or feels alone. Instead, it requires diagnostic testing.
How is lymphoma treated?
To help guide discussions around treatment options, it can help to understand the difference between remission and cure:
- Remission means signs of cancer are reduced (partial remission) or no longer detectable (complete remission)
- Cure means the cancer is completely gone
Lymphoma is generally not considered curable in dogs. But, with treatment, many dogs go into remission and continue to live happy, active lives.
Treatment options may include:
- Chemotherapy protocols designed specifically for dogs
- Steroids, such as prednisone, prescribed specifically for your dog
- Other advanced treatments, such as radiation in certain cases
- Supportive care to manage symptoms and help keep your dog comfortable, including medications for symptoms and nutrition support
Every dog is unique, and treatment plans can vary in cost and intensity. It’s always appropriate to discuss options with your vet that best fit your goals and your dog’s needs.
Will my dog still have a good quality of life?
Treatment for dog lymphoma focuses on quality of life. Many families are pleasantly surprised to see their dog continue to enjoy walks, meals, and time together during treatment.
Chemotherapy for dogs is typically given in smaller, carefully managed doses compared to people to limit severe side effects. The goal is to keep your dog comfortable and prolong life. Most dogs tolerate treatment well. Your veterinarian will closely monitor for side effects and adjust the plan as needed.
What is the life expectancy for dogs with lymphoma?
Life expectancy varies widely and depends on factors such as the type of lymphoma, the stage and substage, and the treatment approach.
In dogs with aggressive forms of lymphoma treated with chemotherapy, remission may last several months to a year or more. Dogs treated at earlier stages of disease and those who are feeling well may have longer survival times. However, treatment can make a meaningful difference in your dog’s life at any stage.
Without treatment or with steroids alone, survival time is often a few months.
It’s important to remember that survival times are often discussed in human terms. These timeframes may sound short to us, but in a dog’s life, this time is meaningful. It can be filled with walks, tail wags, treats, naps in the sun, and time with the people they love.
The goal of treatment is not just more time—it’s more good time.
How can I support my dog with lymphoma?
Daily support plays a key role. Helpful steps include:
- Keeping a log of appetite, energy, and behavior
- Sharing changes promptly with your veterinarian
- Asking about medications for symptoms, if needed
For example, noting when your dog skips a meal or seems more tired than usual can help your veterinarian adjust care promptly.
You are an essential partner in your dog’s care, and your observations help guide thoughtful decisions.
Final thoughts
A lymphoma diagnosis can feel heavy and unsettling. Many pet parents find themselves worrying about what comes next or questioning whether they’re making the right decisions. Those feelings are normal, and it’s okay to take time to process and gather the information you need.
With the support of your veterinarian, many dogs with lymphoma continue to enjoy good days and meaningful time with their families. There’s no single “right” path forward. Whether care includes chemotherapy or comfort-focused support, the goal is always to maintain quality of life. Open conversations with your veterinary team can help ensure each decision is guided by your dog’s needs and what matters most to you.
Frequently asked questions
Frequently asked questions about this topic
In some cases, yes. Blood‑based screening and routine checkups may detect changes before clear symptoms appear. Your veterinarian may recommend screening for older dogs or breeds at higher risk.
Yes. Some dogs appear healthy until lymphoma has progressed. Subtle changes may be the earliest signs.
Certain breeds have higher risk, but lymphoma can affect any dog, including mixed breeds. Some higher-risk breeds include golden retrievers, rottweilers, and boxers.
No. Some lymph nodes are internal or difficult to feel early on, and lymphoma can develop in other places in the body.
There is no proven way to prevent lymphoma. Regular veterinary care supports earlier detection, which may lead to better treatment responses.
Lymphoma is not typically painful in its early stages. Discomfort can develop as the disease progresses, depending on where it is located and how your dog is feeling. You and your veterinarian can work together to monitor your dog’s pain level and adjust their treatment plan accordingly.
Both are thoughtful, valid choices. Treatment like chemotherapy can extend time and maintain quality of life for many dogs, while comfort-focused care (palliative care) prioritizes symptom relief without intensive treatment. The right decision depends on your dog’s health, your goals, and what you feel is best for your pet. Your veterinarian can help you weigh these options with clarity and compassion.
If you notice any new lump on your dog, you should call your veterinarian. In most cases, getting a new lump checked out is not urgent and can be scheduled within a week or so. If you notice other symptoms along with the lump (such as less interest in food or low energy), your dog should see your veterinarian sooner.
