Lymphoma in dogs is one of the most common types of cancer affecting our canine companions. It happens when a type of white blood cell, called the lymphocyte, starts to grow and multiply uncontrollably.
The lymphatic system runs all throughout your dog's body. This includes the spleen, bone marrow, lymph nodes, and other related organs. When these cells turn cancerous, they can spread through the system.
Here, we'll talk about lymphoma and everything you need to know about it. By the end, you'll get a good understanding of what it is, what it looks like, and how it's treated.
What Are the Types of Lymphoma in Dogs?
Vets generally classify lymphoma in dogs according to where it is and how it affects the body.
Multicentric Lymphoma
The most common type of lymphoma in dogs. It usually starts as painless swelling of the lymph nodes all over the body. Multicentric lymphoma in dogs covers about 80 to 85% of all cases.
Aside from the swelling of several lymph nodes in the neck, shoulders, and knees, dogs may also develop fever, weight loss, changes in appetite, and lethargy.
Alimentary Lymphoma
The second most common form is alimentary lymphoma. This is also called gastrointestinal lymphoma in dogs. It usually targets the stomach, intestines, and other key parts of the digestive tract.
Common symptoms of gastrointestinal lymphoma in dogs include frequent vomiting, diarrhea, abdominal pain, loss of appetite, and lethargy.
Mediastinal Lymphoma
Mediastinal lymphoma affects the lymph nodes in the chest cavity and sometimes the thymus gland. Dogs may develop symptoms related to these areas. This includes labored breathing, rapid breathing, coughing, fluid buildup in the chest cavity, and lethargy.
Extranodal Lymphoma
While rare, extranodal lymphoma in dogs can affect organs outside the lymphatic system. This includes the skin, eyes, lungs, kidneys, and nervous system.
Common signs include lumps and red patches on the skin, cloudiness and redness on the eyes, excessive drinking and urination, and seizures and loss of coordination.
Causes of Lymphoma in Dogs
Generally, the causes of canine lymphoma have still not been completely uncovered. However, there are some risk factors that have been suspected.
Genetics and Breed Predisposition
Some breeds are more likely to develop lymphoma.
Rottweilers
Boxers
Scottish Terriers
Basset Hounds
While these dogs have an increased risk, other breeds can also be affected.
Environmental Factors
Dogs exposed to certain chemicals and pollutants may also be at risk of canine lymphoma. Herbicides, pesticides, cigarette smoke, and industrial chemicals are the common factors that have been suspected in cases of lymphoma in dogs.
Immune System Dysfunction
A suppressed and weakened immune system can also be a risk factor for canine lymphoma. It may have a harder time spotting and destroying the abnormal cells before they rapidly multiply. However, this isn’t a guaranteed cause.
Age
Age is another factor. Lymphoma commonly affects middle-aged dogs and seniors. It can also occur in younger dogs, but it is not as common.
What Are the Early Warning Signs of Lymphoma in Dogs?
One of the tricky things about lymphoma is that early on, dogs may seem completely fine. It can be challenging to detect the disease early on. As the disease progresses, some early warning signs of cancer start to show. These include:
Swollen Lymph Nodes. These are firm, round lumps you might feel under the jaw, in front of the shoulders, or behind the knees.
Loss of Appetite and Weight Loss. The cancer and symptoms can affect your dog’s metabolism, causing nausea and loss of appetite. Because of this and malabsorption from lymphoma, dogs can also lose weight.
Lethargy and Fatigue. Dogs with lymphomas often become tired as their bodies are working harder to fight off the disease. They may sleep more and lose interest in playing.
While each type may develop differing symptoms, these are the common early signs pet owners can expect to notice.
How Do Vets Confirm Lymphoma in Dogs?
We’ll start with a physical exam to check for symptoms such as enlarged lymph nodes. Next, our vets will do a series of tests.
Fine-Needle Aspiration. A small needle is used to collect cells from the enlarged lymph nodes. This sample is examined under a microscope and is enough to confirm lymphoma in dogs.
Biopsy. In some cases, obtaining a small piece of tissue can give a more detailed look at the type of cancer.
Bloodwork and Urinalysis. Bloodwork and urinalysis can check for organ function, look for signs of infection, and help rule out other illnesses.
Diagnostic Imaging. X-rays and ultrasounds can be used to identify any other organs that have been affected. This includes the liver, spleen, or chest cavity.
Immunophenotyping. In some cases, we may do a flow cytometry or PCR testing to determine the specific subtype of lymphoma.
To classify the progression, we use a staging system.
Stage | Description |
|---|---|
I | Only one lymph node is affected. |
II | Multiple lymph nodes in one area of the body are affected |
III | Lymph nodes throughout the body are enlarged. |
IV | Cancer has spread to the liver or spleen. |
V | Cancer has spread to the blood, bone marrow, or other organs. |
What Is the Best Treatment for Lymphoma in Dogs?
Lymphoma can’t be 100% cured, but there are options to put the cancer into remission. This means that dogs can still live several years of a good quality of life.
Chemotherapy
The most common method for treating canine lymphoma. While there are a variety of chemical combinations given to dogs, these are the most common ones:
CHOP Protocol. This combination of four drugs includes cyclophosphamide, doxorubicin, vincristine, and prednisone. It’s the gold standard with remission rates over 80 to 90%.
Single-Agent Therapy. For dogs who cannot tolerate certain drugs or afford them, a single medication such as doxorubicin or lomustine can still provide good results.
Radiation Therapy
Another method that can be used is radiotherapy. Radiation can be used for localized forms of lymphoma or as part of a combined treatment plan.
Surgery
Surgery has a limited role in treating lymphoma in dogs, as the cancer is usually widespread. However, it can be useful for a biopsy or if the growth is localized.
Cancer Medications
Some medications, such as rabacfosadine and verdinexor, can help target the proteins involved in cancer growth. These are great supplementary treatment options.
Prognosis and Life Expectancy for Dogs with Lymphoma
Lymphoma in dogs can progress quickly without treatment, usually within a few weeks. Most dogs without treatment survive one to two months after diagnosis. With treatment, dogs can live for about a year or two, depending on the response to treatment.
Dogs with early-stage lymphoma or multicentric lymphoma tend to have better outcomes than other types of canine lymphoma.
“Cancer may change the journey, but it doesn’t take away the love and loyalty our dogs have for us.”
- Dr. Leticia Maia
Final Thoughts
Lymphoma is a serious cancer that evolves quickly. That’s why we must act quicker. Early detection is the most powerful option we have, which is why regular vet visits are essential. Always check your dog’s condition and be on the lookout for the subtlest symptoms.
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