A cancer diagnosis can be frightening and overwhelming. Fortunately, advances in veterinary medicine provide more options than ever for diagnosing, treating, and managing many canine cancers.

Two cancers frequently seen in dogs are lymphoma and mast cell tumors. They are very different diseases, and treatment and prognosis can vary significantly from one dog to another.

The most important first step is obtaining an accurate diagnosis and working with your veterinarian—or a veterinary oncologist when appropriate—to understand the options for your individual dog.

Lymphoma is a cancer of lymphocytes, a type of white blood cell that plays an important role in the immune system. Because lymphocytes are found throughout the body, lymphoma can occur in many locations.

The most common form affects multiple lymph nodes.

One of the most noticeable signs is enlarged lymph nodes, which may feel like firm lumps under the skin, particularly:

• Under the jaw
• In front of the shoulders
• Behind the knees

Some dogs otherwise appear completely healthy when lymphoma is discovered.

Other signs can include:

• Decreased appetite
• Weight loss
• Lethargy
• Increased thirst or urination
• Vomiting or diarrhea
• Difficulty breathing, depending on the location of the disease

Any new or persistent lump should be evaluated by a veterinarian.

A veterinarian may begin by taking a small sample of cells from an enlarged lymph node using a fine-needle aspirate (FNA).

Additional testing may be recommended to better understand the type and extent of the cancer. This can include:

• Bloodwork
• X-rays
• Ultrasound
• Flow cytometry or other specialized testing
• Additional tissue or cell sampling

These results can help the veterinary team determine the most appropriate treatment options.

Chemotherapy is the primary treatment for most forms of canine lymphoma.

There are several treatment protocols, ranging from combinations of chemotherapy medications given over several months to simpler protocols involving fewer medications or visits.

Treatment decisions may consider:

• Type of lymphoma
• Extent of disease
• Overall health
• Age
• Other medical conditions
• Expected quality of life
• Ability to tolerate treatment and veterinary visits
• Cost and family circumstances

Unlike chemotherapy in people, veterinary chemotherapy is generally designed with quality of life as a primary goal. Many dogs tolerate treatment well and continue enjoying normal activities during therapy.

Chemotherapy often produces remission rather than a permanent cure. A dog in remission may have no detectable signs of cancer and may feel very well, although the lymphoma can eventually return.

Mast cell tumors (MCTs) are among the most common skin tumors in dogs.

Mast cells are normal immune-system cells involved in allergic and inflammatory responses. When these cells multiply abnormally, they can form tumors.

One reason mast cell tumors can be difficult to recognize is that they can look like almost anything.

They may appear as:

• A small bump beneath the skin
• A raised or hairless growth
• A soft lump resembling a fatty tumor
• A red or irritated area
• A mass that suddenly changes size

Some mast cell tumors periodically swell and then become smaller again because mast cells release histamine and other inflammatory substances.

Appearance alone cannot reliably determine whether a lump is benign or cancerous.

A simple fine-needle aspirate can often provide valuable information about a skin mass without requiring surgery.

This is especially important with mast cell tumors because some behave relatively predictably while others can be aggressive and spread elsewhere in the body.

A useful rule for pug owners—and dog owners generally—is:

Don't just watch a new lump. Have your veterinarian check it.

Surgical removal is often the first treatment when a mast cell tumor can be safely removed.

After removal, the tumor may be examined by a veterinary pathologist. The pathology report provides important information about how the tumor is likely to behave and whether it was completely removed.

Depending on those findings, additional treatment may include:

• Additional surgery
• Radiation therapy
• Chemotherapy
• Targeted medications
• Monitoring

Some mast cell tumors are successfully treated with surgery alone. Others require more extensive treatment.

There is rarely one correct treatment decision for every dog diagnosed with cancer.

Veterinarians and families may consider:

• Whether the cancer has spread
• Available treatment options
• Expected benefits of treatment
• Possible side effects
• Other medical conditions
• Age and overall health
• Comfort and quality of life

For some dogs, aggressive treatment may provide meaningful additional time with an excellent quality of life. For others, a less intensive approach focused on comfort may be more appropriate.

The goal should always be to make decisions based on the individual dog, rather than the diagnosis alone.

Schedule an examination if you notice:

• A new lump or bump
• A mass that changes size, shape, or appearance
• Enlarged lymph nodes
• Unexplained weight loss
• Persistent loss of appetite
• Unusual fatigue
• Recurrent vomiting or diarrhea
• Unexplained swelling
• Changes in breathing
• Any significant change from your dog's normal behavior or health

Not every lump is cancer, and many symptoms can have other causes. Veterinary evaluation is the only way to determine what is happening.

A referral to a board-certified veterinary oncologist does not automatically mean choosing chemotherapy or aggressive treatment.

An oncology consultation can help families understand:

• Exactly what type of cancer their dog has
• Whether additional testing is useful
• Available treatment options
• Expected outcomes with and without treatment
• Potential side effects
• Costs and time commitments
• Palliative and comfort-care options

Having this information allows families to make informed decisions that are right for their dog.

Cancer care isn't only about extending life. It is also about protecting the dog's comfort and ability to enjoy that life.

Continue watching the things that matter to your dog:

• Are they eating and drinking?
• Are they comfortable?
• Do they enjoy interacting with their family?
• Are they interested in favorite activities?
• Can pain, nausea, or other symptoms be controlled?
• Are there still more good days than difficult ones?

These observations can be just as important as medical test results when making treatment decisions.

The word cancer can make the future feel immediately uncertain, but every diagnosis is different.

Some cancers can be removed surgically. Some respond very well to chemotherapy. Others can be managed for meaningful periods of time while maintaining a good quality of life.

Ask questions, understand the diagnosis and available options, and work with your veterinary team to determine what makes sense for your dog.

Pug Rescue of Florida & Georgia
Providing education and resources to help pug families make informed decisions about their dogs' health and care.

This information is intended for general education and is not a substitute for veterinary diagnosis or treatment.