Reviewed by Dr. Fiona Lee
If your dog has lymphoma, you're likely feeling overwhelmed and heartbroken. You may have thought your pup had something much milder, and you were shocked by the news. Or you may have found out after rushing your dog to an emergency veterinarian. No matter how the diagnosis was made, deciding what to do next can feel daunting.
Lymphoma is one of the most common cancers seen in dogs, but facing it personally is a completely different matter. This guide will help you better understand the symptoms and types, and how your veterinarian can help you choose among treatment options.
What Is Lymphoma in Dogs?
Lymphoma refers to cancers affecting a type of white blood cell called a lymphocyte. It can affect any part of the body, but it's more common in immune-related organs like the lymph nodes.1 Lymphoma can affect any breed, male or female, but it's more common in middle-aged and older dogs.2
Some breeds are more susceptible, such as Golden Retrievers, Bulldogs, Basset Hounds, St. Bernards, Scottish Terriers, Airedale Terriers, Labrador Retrievers, English Springer Spaniels, Bernese Mountain Dogs, Rottweilers and Boxers.3
Causes of Lymphoma in Dogs
The exact cause of lymphoma is unclear.1 The only clear correlation is genetics, since some breeds are more susceptible.3
Other potential risk factors that are still debated include:4
- Viral or bacterial infection
- Herbicide exposure
- Strong magnetic fields
- Immune system problems
Types of Lymphoma in Dogs
Lymphoma can present in many different forms, such as:1
- Multicentric (nodal) lymphoma: This is the most common form in dogs, accounting for about 80% of cases. It often first presents with enlarged lymph nodes.
- Cutaneous lymphoma: This is a slower-progressing cancer. It may start as lesions on the skin or mouth and is often mistaken for an infection, allergy or even gum disease at first.
- Alimentary (gastrointestinal) lymphoma: This affects the digestive system, including the stomach or intestines.
- Mediastinal lymphoma: This is a cancer of the lymph tissue between the lungs in the chest cavity.5
- Extranodal lymphoma: This is a term for lymphoma that affects organs like eyes, kidneys, skin or bones.2
- Bone marrow lymphoma: This is more commonly referred to as leukemia.5
Stages of Lymphoma in Dogs
Veterinarians categorize lymphoma based on how far it's progressed, from Stages I to V. Unfortunately, all stages of lymphoma are fatal, but some progress more rapidly than others. The stage can impact the treatment and prognosis:2
- Stage I: A single lymph node or single organ, except bone marrow (this stage is rare)
- Stage II: Many lymph nodes in a regional area (this stage is rare)
- Stage III: Generalized lymph node spread
- Stage IV: Any of the above stages, plus the spleen or liver
- Stage V: Any of the above stages, plus blood, bone marrow or other organs.
Lymphoma can also be categorized as B-cell or T-cell. T-cell tends to be more aggressive (high-grade) overall. In addition, lymphoma may be characterized as small cell or large cell. Small cell moves slower. Large cell is fast and aggressive and needs quicker treatment.6
Symptoms of Lymphoma in Dogs
Lymphoma symptoms vary based on the type of lymphoma your dog has. Some early warning signs might include:1
- Excessive thirst and urination: Lymphoma may be diagnosed when this is the only clinical sign.
- Swollen lymph nodes: An early sign of multicentric lymphoma. The lymph nodes feel like rubbery, hard lumps under your dog's skin. A common location is under your dog's jaw or behind the knee.
- Dry, flaky or red patches of skin: May be the first sign of cutaneous lymphoma.
- Vomiting, diarrhea and weight loss: Can be signs of gastrointestinal lymphoma.
- Excess panting or hard breathing: Might be the first sign of mediastinal lymphoma.
When the cancer is more progressed, you might notice symptoms like:2
- Fever
- Weakness or lack of energy
- Loss of appetite or significant weight loss
- Dehydration
- Excessive trouble breathing or trouble swallowing
- Kidney failure
- Blindness
- Seizures
- Bone fractures
How Is Lymphoma Diagnosed?
It can be easy to mistake early lymphoma for other diseases, so your veterinarian will run a series of tests after doing a full physical exam.1 You may need to take your dog to an internal specialist for some tests.
These include:2
- Fine needle aspiration (FNA): Using a small needle to get a sample from an organ or lymph node, which is analyzed under a microscope.
- Biopsy: If the FNA is inconclusive or not practical due to the location, your veterinarian might surgically remove a sample.
- Blood tests and urinalysis
- Immunohistochemistry or flow cytometry: Distinguishes between B-cell and T-cell lymphoma.
- X-ray or ultrasound: Helps determine the stage.
- CT-scan and endoscopy: For staging or biopsy.
- PARR test: Analyzing the DNA of a sample if other tests are inconclusive. It can help distinguish between lymphoma and inflammatory cells.7
Prognosis for Dogs With Lymphoma
If your dog has lymphoma, you'll need to prepare for a tough road. Dogs can go into remission with chemotherapy, but this isn't a cure. At some point, the cancer will return.1 Because of this, the main goal is improving your dog's quality of life and getting a little extra time together.2
If you choose chemotherapy, your veterinarian will help you with practical expectations based on the cancer stage and your dog's health. For example, about 70% to 90% of dogs with multicentric lymphoma reach at least partial remission and a median survival of nine to 13 months.1 Cutaneous lymphoma cases might get three to six months of remission. Dogs with a low-grade (less aggressive) lymphoma may survive longer than two years. Even palliative care with just prednisone can bring one to two months of remission or longer. But without any treatment, a dog may have only four to six weeks.2
These examples may be tough to read, but every dog is different. Your veterinarian can help you determine what's likely for your unique situation.
Treatment Options for Lymphoma
Your veterinarian or oncologist will advise you on the best treatment options based on the type of cancer and staging. These might include:
1. Chemotherapy
The most common and effective treatment is chemotherapy, which can be given through pills or an IV. Because the doses for dogs are lower than for humans, many dogs tolerate chemotherapy well. This doesn't mean your dog won't have serious side effects, but it's far less likely.1
Common chemotherapy options include, but aren't limited to:
- CHOP: A protocol of different chemotherapy agents given over six months, with the highest remission rate and survival time. Often recommended for multicentric lymphoma.1
- Single-agent chemotherapy: Using only one type of chemotherapy. It may not be as effective as combination protocols, but there are exceptions.2 For example, lomustine tends to work better than CHOP for cutaneous lymphoma.1
Some safety measures to keep in mind:1
- Oral chemotherapy (pills) shouldn't be crushed or broken. Wear gloves when giving your dog the pills, and wear gloves to clean up vomit or potty accidents in the first day or two.8
- Your dog may have appetite loss, lethargy, mild vomiting or diarrhea for one or two days after treatment. But they won't lose their hair like people do.
- You don't need to separate your dog from other pets or people.8 This means your pup can even still sleep in bed with you.9
- Your dog will need regular veterinary visits to monitor for serious but rare side effects, like tissue, heart or kidney damage, or reduced white blood cells.
2. Additional treatments
Other treatments your veterinarian might consider (often in combination with chemotherapy) include:4
- Radiation
- Surgical tumor removal
- Bone marrow transplant2
- Clinical trials to test new treatments: The trial may even cover some of the treatment's cost.10
- Verdinexor: An antineoplastic drug approved in 2021. So far, it's not as effective as chemotherapy.2
Of course, none of these treatments are free. If you have pet insurance, it will likely cover the majority of the cost, and you may just have a deductible or small percentage to cover yourself.
3. Palliative care
Many pet parents choose palliative care, which involves treating their dog only with prednisone rather than more aggressive therapies. Prednisone can bring remission, but typically for only one to two months (though some dogs may experience longer).2
Dog owners may choose this route if the chemotherapy is no longer working or if the prognosis with chemotherapy doesn't justify extensive veterinary visits and aggressive treatments.
Remember: When it comes to choosing the best route for your dog, there isn't a wrong answer. Follow the path that you feel is best for your unique situation.
4. Medications for discomfort
Whether on palliative or a more aggressive treatment, your dog may need medications to ease discomfort, such as:
- Antinausea or antivomiting medicine
- Antidiarrheals
- Prophylactic antibiotics for some chemo side effects
- Pain medicine
- Appetite stimulant
- Benadryl or steroids for allergic reactions to chemo
In addition, you can take other steps to make your dog more comfortable, like adding nonskid rugs to slippery floors, raising food and water dishes so they're easier to reach, and adding ramps to help your pup get onto the couch or bed.
Can Lymphoma in Dogs Be Prevented?
Unfortunately, there aren't any known methods of preventing lymphoma in dogs. The best "prevention" is to catch it early by watching for symptoms and seeing your veterinarian right away. If your veterinarian suggests seeing a specialist for a test, don't put it off. In some regions, specialists have a monthslong waiting list.
End-of-Life Care for Dogs With Lymphoma
No one wants to think about saying goodbye. But pet owners have the sacred responsibility of caring for their pets to the very end, making decisions based on prognosis and quality of life.
Your veterinarian will help you know if it's time to consider euthanasia. This may happen if your dog's symptoms worsen or new symptoms emerge. Signs of worsening pain can include avoiding favorite activities, pacing (especially at night), sleeping or hiding in strange places, excessive panting, acting weaker on their feet or not wanting to move, or refusing to eat.11 A quality of life assessment can help.12
As hard as it is, you might contact a local at-home euthanasia veterinarian ahead of time so you're ready if your dog's health takes a sudden downturn. These veterinarians or your regular veterinarian can also recommend support groups and resources to help you emotionally.
Your Veterinarian Can Help You Navigate This Journey
Navigating a lymphoma diagnosis can be emotionally difficult. But the more you understand about treatment options and what to expect, the more you can help your sweet furry friend. Every dog is different, and working closely with your veterinarian is the best way to create a care plan that fits your pet's unique needs. While a lymphoma diagnosis can be heartbreaking, there is hope. With support, many dogs can enjoy extra time filled with love, comfort and quality moments.
Pets Best Can Help You Keep Your Dog Healthy
Pet insurance is a great way to help your dog, even after a lymphoma diagnosis. At Pets Best, our dog insurance plans can be customized for your pet's unique needs. In addition, Pets Best policyholders can speak to a veterinary expert anytime through a 24/7 Pet Helpline.
Sources/ Citations
1. "Canine lymphoma research," (n.d.), Purdue University College of Veterinary Medicine, https://vet.purdue.edu/wcorc/cancer-research/canine-lymphoma-research.php
2. "Lymphoma in dogs," Timothy M. Fan (4/2025), Merck Veterinary Manual, https://www.merckvetmanual.com/circulatory-system/lymphoma-in-dogs/lymphoma-in-dogs
3. "How to know if your dog is at a high risk for lymphoma," (3/14/2025), Imprimed, https://www.imprimedicine.com/blog/high-risk
4. "Malignant lymphoma in dogs," Timothy M. Fan (9/2024), Merck Veterinary Manual, https://www.merckvetmanual.com/dog-owners/blood-disorders-of-dogs/malignant-lymphoma-in-dogs
5. "Lymphoma cancer in dogs," Spela Bavcar (1/6/2022), Small Animal Specialist Hospital, https://sashvets.com/diseases/lymphoma-cancer-dogs/
6. "Understanding the differences in the types of canine lymphoma," (4/11/2025), Imprimed, https://www.imprimedicine.com/blog/types-of-canine-lymphoma
7. "PCR for antigen receptor rearrangements (PARR)," (n.d.), Michigan State University Veterinary Diagnostic Laboratory, https://cvm.msu.edu/vdl/laboratory-sections/anatomic-surgical-pathology/biopsy-service/pcr-for-antigen-receptor-rearrangements-parr
8. "13 most frequently asked questions about chemotherapy," (n.d.), Advanced Veterinary Care Center, https://advetcc.com/cancer-care/frequently-asked-questions-about-chemotherapy/
9. "Chemotherapy for pets," (n.d.), Hampton Park Veterinary Hospital, https://hamptonparkvets.com.au/chemotherapy-pets-hampton-park-lynbrook-narre-warren-south
10. "Canine lymphoma trials," (n.d.), Purdue University College of Veterinary Medicine, https://vet.purdue.edu/wcorc/clinical-trials/canine-lymphoma.php
11. "When is it time?" (n.d.), Compassionate Pet Vet, https://compassionatepetvet.com/pet-euthanasia/when-is-it-time-to-choose-euthanasia/
12. "Quality-of-life assessment," (n.d.), Lap of Love, https://www.lapoflove.com/quality-of-life-assessment