What Is Lymphoma in Dogs: Causes, Symptoms, and Treatment

What is Lymphoma in Dogs?

Lymphoma is a type of cancer in dogs that results from the uncontrolled reproduction of lymphocytes (white blood cells that play an important part in the dog’s immune system). Lymphoma is a blanket term that encompasses several types of lymphomas. 

According to the Purdue University College of Veterinary Medicine, lymphoma in dogs is one of the most common cancers, collectively representing about 7 to 14% of all canine cancer diagnoses.

Because lymphocytes circulate, canine lymphoma is classified as a systemic disease and requires systemic treatment. Lymphoma in dogs usually affects the lymphatic system (lymph nodes, bone marrow, and spleen). However, it can occur in any organ in the body.

What are Other Terms for Canine Lymphoma in Dogs?

Other terms for canine lymphoma in dogs are malignant lymphoma and lymphosarcoma. The prefix malignant describes the nature of the tumor, meaning it is invasive and metastasizing. 

The term lymphosarcoma is a non-specific umbrella term that includes all malignant tumors arising from lymphatic tissue. 

Lymphoma is sometimes called by the organ it affects. Cutaneous dog lymphoma involves the skin, and alimentary lymphoma affects the gastrointestinal tract. 

Types of Lymphoma in Dogs

There are four different types of lymphoma cancer in dogs. Each affects different parts of the body and has a different prognosis. Let’s take a closer look at each type.

Multicentric Lymphoma. Multicentric lymphoma is the most common type of lymphoma and, according to VCA Hospitals, accounts for 80-85% of all lymphoma cases. It affects the lymph nodes and is also called systemic lymphoma. One of the main signs of multicentric lymphoma is visibly enlarged lymph nodes.

Alimentary Lymphoma. Alimentary lymphoma is the second most common type of lymphoma, and it affects the dog’s gastrointestinal tract. According to the American Kennel Club (AKC), it accounts for 10% of all canine lymphomas. Alimentary lymphoma in dogs causes vomiting, diarrhea, decreased appetite, and weight loss.

Mediastinal Lymphoma. Mediastinal lymphoma in dogs is a less common form of lymphoma. It affects the lymphoid organs in the chest, including the thymus and mediastinal lymph nodes. Mediastinal lymphoma in dogs is very aggressive and usually causes coughing and difficulty breathing.

Extranodal Lymphoma. Extranodal lymphoma is rare and affects specific organs (eyes, skin, lungs, kidneys, central nervous system). The MERCK Veterinary Manual states that the most common form of extranodal lymphoma is cutaneous lymphoma, which affects the skin, causing skin nodules and lesions.

How Fast Does Lymphoma in Dogs Progress?

Lymphoma in dogs progresses rapidly. This is because most lymphoma types in dogs are high-grade and prone to metastasis. The higher the tumor grade, the more aggressive the tumor.

According to The Pet Oncologist, when it comes to canine lymphoma, “if left untreated, most dogs reach terminal stages one to two months from presentation.”

What Causes Lymphoma in Dogs? 

The exact cause of lymphoma in dogs is unknown. There are several potential risk factors, including those listed below:

• Breed. A study shows that some dog breeds are more likely to develop lymphoma. Such breeds are Rottweilers, Dobermans, Bernese Mountain Dogs, and Boxers. Retrievers and Terriers are also at risk of developing lymphoma.
• Environmental Factors. The Whole Dog Journal mentions that a study from 1994 found a link between herbicides and canine lymphoma. However, the study was re-analyzed and the results were not confirmed.
• Compromised Immunity. In humans, a compromised immune system is a risk factor for lymphoma. It is suggested that the same may be true for dogs, but this has not yet been proven.

What Are the First Signs of Lymphoma in Dogs?

The first sign of lymphoma in dogs is enlarged, firm, and non-painful lymph nodes. A lymph node with cancerous changes will feel like a rubbery yet hard lump just under the dog’s skin.

However, not all enlarged lymph nodes indicate lymphoma. Also, it is possible for a dog to be sick with lymphoma without a striking lymph node enlargement. Therefore, it is vital to have your dog regularly checked by a veterinarian.   

What Are the Early Signs of Lymphoma in Dogs? 

In addition to enlarged lymph nodes, which are common in all lymphoma types in dogs, the clinical signs and symptoms depend on the exact form of lymphoma.

Some of the early symptoms of canine lymphoma are listed below: 

• Lethargy or weakness
• Fever
• Loss of appetite
• Vomiting, with or without diarrhea
• Dramatic weight loss 
• Abdominal pain
• Dehydration
• Skin nodules and lesions
• Swelling of the face or legs 
• Increased thirst
• Frequent urination

These signs and symptoms are not specific to lymphoma in dogs. Therefore, if your dog is showing some of them, schedule an appointment with your veterinarian.   

Diagnosing Lymphoma in Dogs 

To diagnose lymphoma in dogs, a veterinarian will first perform a physical examination, paying close attention to the lymph nodes. 

To reach a definitive diagnosis of lymphoma, the veterinarian will recommend a fine-needle aspiration, which involves taking a cell sample from the lymph node and analyzing the cancer cells under a microscope. If this is not possible due to the lymph node’s location, the vet performs a biopsy, taking a tissue sample for analysis. This can help differentiate between T-cell lymphoma and B-cell lymphoma.

Based on the results, the vet may order some advanced diagnostic tests, such as bone marrow aspiration and flow cytometry (analyzes physical and chemical characteristics of cells). To evaluate the dog’s overall health, blood work, urinalysis, chest x-rays, and abdominal ultrasound will be performed.

The vet may then refer a dog with lymphoma to a vet specializing in oncology for a more definitive diagnosis. The veterinary oncologist can also recommend specific treatment options.

How Do You Treat Lymphoma in Dogs?

Cancer in dogs treatment is complex and sometimes requires using several approaches together. Here is a closer look at the different treatment options for lymphoma cancer in dogs.

Chemotherapy. The gold standard for lymphoma treatment is chemotherapy. The chemotherapy protocol is called CHOP and consists of multiple chemotherapy drugs: vincristine, cyclophosphamide, doxorubicin, , and L-asparaginase. One side effect is hair loss, which is usually observed in Poodles and Old English Sheepdogs. Other side effects of chemotherapy include gastrointestinal upset and bone marrow suppression.

Radiation Therapy. Radiation is recommended for dogs with localized forms of lymphoma. The treatment can be used alone or in conjunction with other approaches, such as surgery and chemotherapy.

Surgery. Surgery is an option for treating canine lymphoma. However, due to its limited use and benefits, it is rarely recommended. Surgical treatment is pursued only if the lymphoma has not spread.

Laverdia-CA1 Tablets. Laverdia-CA1 (Verdinexor) is an FDA-approved oral tablet for treating canine lymphoma. The active ingredient works by stopping proteins from leaving the cancer cells’ nuclei, thus preventing the growth and spread of cancerous cells in dogs.

In addition to the mainstream treatments, you can talk to your vet about holistic options that can help improve the dog’s quality of life.

Cannabidiol (CBD) Products. CBD is one of the latest hits in the pet care industry and can help dogs with lymphoma by reducing anxiety and decreasing inflammation. We recommend getting a pet CBD oil for dogs with lymphoma product from a reputable brand like Honest Paws. 

What Can I Do To Prevent Lymphoma in Dogs?

There is no exact answer to the question of how to prevent cancer in dogs. Lymphoma is not completely preventable. However, there are some things pet owners can do to decrease the risk of canine lymphoma:

• Healthy Lifestyle. A healthy lifestyle for dogs consists of proper nutrition (e.g., a diet that is rich in health-boosting ingredients) and regular physical activity for dogs. These approaches support your dog’s overall health and prevent obesity.
• Limited Chemical Exposure. Carcinogens are everywhere, and complete prevention from exposure to them is impossible. However, reducing the use of certain products, such as herbicides, can be helpful.
• Regular Vet Checkups. Since regular veterinary care is expensive, we suggest getting a good pet insurance plan, like OneVet. The plan provides 24/7 online access to a licensed vet and up to $3,000 in emergency funds for $19.99 per month.

Is Lymphoma in Dogs Curable?

Lymphoma in dogs is responsive to treatment, especially chemotherapy. However, the disease is not cured, only managed.

When managing canine lymphoma, one of the main aspects that need to be considered is the dog’s quality of life, during the treatment protocol and afterward.

Can Autoimmune Disease Cause Lymphoma in Dogs?

No, autoimmune disease cannot cause lymphoma in dogs. Certain autoimmune conditions, however, appear to increase the risk of lymphoma. 

“Dogs with immune-mediated thrombocytopenia had a greater occurrence of lymphoma than dogs without immune-mediated thrombocytopenia” found a study “Immune-Mediated Disease as a Risk Factor for Canine Lymphoma,” published in Cancer in 1992. 

Autoimmune issues are found to increase the risk of lymphoma in humans. Certain types of lymphoma are more common in people with rheumatoid arthritis, for example. 

The exact role of autoimmune disease in the complex development of dog lymphoma is poorly understood. 

Does a Weak Immune System Raise the Risk of Lymphoma in Dogs?

Yes, a weak immune system raises the risk of lymphoma in dogs. The link is not proven in dogs but confirmed in people. 

Suppression of the immune system is a significant risk factor for human lymphoma. HIV-positive people receiving immunosuppressive drugs have a high incidence of lymphoma. 

A weakened immune system is believed to have the same effect on dogs because canine and human lymphoma share similar behaviors. 

How Long Does a Dog Live with Lymphoma?

According to Tufts Now, the median survival time for dogs with untreated lymphoma is only two or three months. Dogs receiving the standard chemotherapy treatment can live for 10 to 14 months.

The prognosis is better for dogs with complete remission of lymphoma. However, the chances of this happening depend on the type of lymphoma, its stage, and the promptness and adequacy of the treatment.