Does My Pet Have Cancer?: Signs of Cancer in Pets

Medical articles
A multi-colored dog with sad eyes lying on a brick patio.

Cancer is one of the scariest diagnoses an owner can receive for their pet. Upon diagnosis, many owners want to know how it could have happened or if it could have been caught sooner. While preventing cancer is difficult, and in many cases, impossible, knowing what to look for and having pet insurance that covers cancer may help with an earlier diagnosis and prevention of cancer spread.

What is cancer?

Cancer, also known as neoplasia, is an unusual and often rapid growth of abnormal cells within the body. While any part of the body can develop cancer, it may not be obvious in the early stages. Certain warning signs or symptoms may help you determine if your pet needs to be evaluated by a veterinarian. He or she will perform a physical examination and discuss running tests such as lab work or x-rays to assess your pet further.

Unusual Masses

A common symptom of cancer is the development of an unusual growth or mass on your pet, also known as a tumor. Sometimes abnormal cells will grow to form masses that are benign tumors, such as fatty tumors like lipomas. Benign tumors occur in one area of the body, such as beneath the skin, and do not spread to other parts of the body or invade or change the surrounding structures or tissues. These types of tumors are not cancer.

Other types of tumors form masses that will eventually spread to other areas within your pet such as the lungs. These types of tumors are known as metastatic tumors. Discovering and removing these tumors quickly can help prevent their spread. In some cases, veterinarians can take a sample of the tumor and examine it under a microscope to determine if it is benign or cancerous. This is known as a fine needle aspirate with cytology.

Unexplained Weight Loss

Another common symptom of cancer is rapid and unexplained weight loss. While weight loss is not an exclusive symptom of cancer, pets with cancer commonly lose weight. Cancer requires a lot of bodily resources because of its rapid growth, which can take a significant toll on your pet’s body. This can result in poor absorption and use of the nutrients your pet normally gets from food. Your pet may seem thin or the spine and ribs may appear more noticeable than usual. If your pet has lost a lot of weight recently, especially if he or she has been eating normally, a trip to the veterinarian’s office may be in order. Decreased Appetite or Activity Level

Eating less or sleeping a lot are not just signs of cancer. A wide variety of issues can cause these symptoms, such as arthritis, dental disease, or infection. However, because of how tough cancer is on a pet’s body and the pain and organ dysfunction that can result, eating or playing much less than usual is certainly an early warning sign that something is not right. Your veterinarian will be able to help determine what is causing these symptoms and help you decide what to do next.

Bleeding, Bruising, or Pale Appearance

Cancerous tumors often bleed easily. The rapid growth of a tumor requires more blood supply than regular cells, so masses that bleed significantly or unexpected bleeding or bruising in the mouth, nose, or under the skin may be an indicator that cancer is growing in those areas. Some cancers lead to decreased production of cells within the bloodstream, such as red blood cells or platelets. This can lead to a pale appearance in your pet, especially on the inside of the ears or the gums.

Other Signs

Other signs of cancer include coughing, throwing up/vomiting, or diarrhea/loose stool. These symptoms are less commonly associated with cancer and more commonly due to other problems such as respiratory tract infections, pneumonia, eating table food, or stress. The likelihood of cancer may be increased if these symptoms are severe, have been present awhile and have gotten progressively worse, or are coupled with other common signs of cancer. Regardless, these types of signs or symptoms should warrant an evaluation by your veterinarian for diagnosis and/or treatment.

Next Steps

If you suspect cancer in your pet, call your veterinarian’s office to set up an appointment for an evaluation. Discuss any unusual symptoms your pet has had and point out any masses you have noticed. Try to give your veterinarian an idea of how long the problems have been present and how quickly they have gotten worse. Be sure to discuss your concerns with your veterinarian and what to expect from further testing. If your veterinarian determines that your pet has cancer, ask him or her if a consultation with a veterinary oncologist would be an appropriate next step. Veterinary oncologists specialize in treating cancer and may be better able to help you determine what can be done for your pet.