If a lump or bump pops up on your pet, the first thought that likely runs through your mind is “cancer.” However, not every lump is cancerous, and many benign masses can crop up that do not significantly affect your pet’s health. Without a thorough veterinary exam and diagnostic testing, there is no way to know the cause of your pet’s mass, so always schedule an appointment if a suspicious lump appears. 

After your family veterinarian determines that the mysterious mass is cancerous, they may refer your furry pal to Animal Internal Medicine and Specialty Services (AIMSS). We are proud of our cutting-edge oncology department that pursues the latest in veterinary oncology to offer our cancer patients the best treatment and prognosis. Some of the most common cancers we see are listed below. 

Most common cancers in pets

Determining the true number of cancer cases in dogs and cats in the U.S. is not easy, since not all pets receive medical care or a definitive cancer diagnosis. However, it is estimated that almost 50% of dogs over age 10 will develop cancer. Generally, more information is known about cancer in purebred dogs, and less information about cancer in cats. The most common forms of cancer seen in cats and dogs include:

  • Lymphoma — Lymphoma is the most frequently diagnosed cancer among all types of feline cancer. Cats of any age can get lymphoma, although most affected cats are 10 to 12 years old. Unvaccinated outdoor cats are at an increased risk, because of their greater exposure to feline leukemia infection. And, cats routinely exposed to tobacco smoke are at elevated risk for gastrointestinal lymphoma, the most common feline form. Depending on the lymphoma type that is present, signs may include weight loss, poor appetite, lethargy, or swollen lymph nodes. In general, dogs enjoy a longer period of high-quality, disease-free time than cats after chemotherapy treatment, but some cats can survive for a year or more after the initial diagnosis.
  • Osteosarcoma — Osteosarcoma is the most common bone cancer in dogs, and occurs most frequently in large and giant breeds. This cancer typically affects the long bones in the limbs, but can affect any bone in any pet, causing swelling, lameness, and pain. Sadly, this cancer is highly aggressive, and can quickly metastasize to the lungs, lymph nodes, and other bones.
  • Mast cell tumor — Mast cell tumors are the most common skin tumors in dogs, and can vary in appearance and severity. These tumors typically appear on or under the skin as a lump that can be red, ulcerated, swollen, hairless, or covered in hair. Surgical removal is generally curative for lower-grade mast cell tumors, as long as the surgical margins can be wide enough to ensure every cancerous cell has been removed. Cutaneous mast cell tumors in cats are typically benign, and surgical removal is often the only treatment necessary. In severe grades, or mast cell tumors in the internal organs of cats, chemotherapy and radiation therapy are also indicated.
  • Mammary gland cancer — In unspayed female animals, tumors can attack the mammary chain, quickly growing into large, ulcerated masses that are commonly near the nipples. In dogs, malignant mammary masses are fatal about 50% of the time, while that number skyrockets to a 90% fatality rate in cats. By spaying your pet before her first heat cycle, you can drastically cut her chances of developing mammary cancer.
  • Melanoma — Melanoma is one of the most common oral cancers in dogs that frequently affects pets with darkly pigmented gums, tongues, and lips. These tumors can create issues with chewing, drinking, and swallowing, causing your pet to drool more, or paw at the mouth. Complete surgical removal is often difficult because of the location, and chemotherapy and radiation therapy are ineffective treatments.
  • Squamous cell carcinoma — Squamous cell carcinoma is a cancer that commonly affects cats in cutaneous or oral forms. Cutaneous squamous cell carcinoma routinely attacks white or light-colored cats, forming on the ears, face, or anywhere exposed to extended direct sunlight. Surgical removal of small lesions is usually curative, but radiation therapy may also be warranted. Oral squamous cell carcinoma is seen more frequently in cats who live in a smoking household. Grooming second-hand carcinogens off their fur can cause cats to develop oral squamous cell carcinomas, which appear as ulcerated masses, and are aggressive, locally invasive, and difficult to control.

As in people, numerous cancers can affect pets, which makes prompt, accurate diagnosis critical for the best outcome for your beloved companion. 

Cancer warning signs in pets

Since so many forms of cancer can affect pets, warning signs are equally varied. The following signs do not always indicate cancer, but may point to a cancer process:

  • Abnormal or rapidly growing lumps
  • Sores that do not heal
  • Appetite and weight loss
  • Bleeding or discharge from body openings
  • Difficulty eating, swallowing, or breathing
  • Lameness or stiffness
  • Difficulty urinating or defecating
  • Abdominal swelling
  • Persistent diarrhea or vomiting

The sooner you schedule a diagnostic appointment, the sooner your pet can begin treatment, and have a better prognosis. 

If you notice any of the above potential cancer warning signs in your beloved pet, don’t hesitate. Make an appointment with your family veterinarian to determine the cause and, if your pet is diagnosed with cancer, request a referral to our state-of-the-art oncology department. We will give your cherished pet the best chance at beating their diagnosis.