Sick dog

Cancer is the leading killer of older dogs. The good(ish) news: While not every type of cancer can be detected by looking at and feeling your dog, many can.

It’s important for pet parents to be able to recognize the common signs of a cancerous tumor, so you can get your dog treatment early in the course of the disease, when it is most likely to be successful.

Is It a Tumor? 

Dogs develop lumps and bumps for many reasons other than cancer. Cysts, hair follicles that become blocked, abscesses, bug bites, hematomas (blood clots), and more can all be mistaken for a tumor.

What’s more, many types of tumors are benign (= unlikely to invade surrounding tissues or spread to other parts of the body). Examples of common benign tumors in dogs include lipomas (fatty tumors), papillomas (warts), sebaceous adenomas, and histiocytomas. In other words, don’t panic if you find a new lump or bump on your dog.

That said, you should take new lumps and bumps seriously. Even if your dog does not have a cancerous tumor, he may be uncomfortable and require treatment.

If your dog has a lump on it’s cheek, our article on causes for a dog’s swollen cheek might help.

What Cancerous Tumors Look and Feel Like

While it’s impossible to conclusively determine whether or not a lump or bump is a cancerous tumor just by looking at it and feeling it, any of the following signs of cancerous tumors should raise your level of suspicion:

  • The mass is growing or changing quickly.
  • The overlying skin is discolored or appears abnormal in other ways.
  • You can’t feel discreet edges to the mass.
  • Your dog has other worrisome symptoms like pain, abnormal behaviors, weight loss, poor appetite, lethargy, etc.

If you think your dog might have a cancerous tumor, make an immediate appointment with your veterinarian. He or she will take a complete health history, perform a thorough physical examination, and may recommend taking a sample of cells or tissue from the mass for identification.

Sometimes, the veterinarian can simply look at it under the microscope in the clinic but often, it’s best to send the sample to a pathologist who specializes in diagnosing cancer.

Will It Go Away on Its Own?

Some types of benign lumps and bumps will go away on their own. For example, a hematoma that forms after rough play at the dog park should be absorbed by the body over the course of a week or so. If your veterinarian has diagnosed your dog with a benign mass, he or she may prescribe appropriate treatment or recommend that you simply keep an eye on it to make sure it behaves in the expected manner.

On the other hand, cancerous tumors will not get better on their own. In fact, they will only get worse and harder to deal with over time. Early diagnosis and treatment is key to the management of cancerous tumors in dogs.

Treatment Options for Cancerous Tumors in Dogs

Appropriate treatment for a cancerous tumor depends on the type of cancer involved, how advanced or widespread it is, and the dog’s overall health.

Surgery is a common first-line therapy. Small tumors are easier to completely remove, which improves the chances of a cure or at least a longer disease-free interval.

Your veterinarian may recommend chemotherapy if cancerous cells are likely to have spread to other parts of the body. Pet parents may be hesitant to put their dogs through chemotherapy because they are familiar with how grueling these treatments can be for people. However, veterinarians typically take a milder approach with dogs so serious side effects occur much less frequently.

Radiation therapy is another treatment option that is especially useful if a cancerous tumor cannot be completely removed through surgery. Clinical trials that involve experimental treatments like immunotherapy may also be an option.

Oftentimes, veterinarians recommend treating a pet’s cancer in multiple ways to increase the likelihood of a successful outcome.

Addressing a pet’s symptoms to maintain a good quality of life is a vital part of cancer treatment, even if you decide against more aggressive therapies. Your veterinarian may recommend medications to relieve pain or nausea, as well as changes in diet, antioxidants, omega-3 fatty acid supplements, and other interventions that can make your dog feel significantly better and thrive as a cancer patient and survivor.