Three Common Signs of Oral Cancer

By: MJ Redman, DVM

TVMA Member
San Antonio, TX.

Published August 2017

The oral cavity is the fifth most common site for cancer in dogs and the third most common site for cats. Most oral tumors are treatable if detected early, and there are a variety of treatment options that can help most pets.

The term “cancer” is generally reserved for malignant tumors, which are those that can metastasize or spread to other parts of the body. Neoplasia is an abnormal growth of tissue, and if that tissue forms a mass, it is called a tumor. Doctors often use the term “epulis” to describe a mass on the gum tissue, giving off the perception that the growth is benign. However, an epulis is any abnormal growth on the gum tissue, but whether that growth is benign or malignant can only be determined by further testing.

Common Oral Tumors and Types of Cancer in Dogs and Cats

One of the most common growths in a dog’s mouth is a canine acanthomatous ameloblastoma, a slow-growing tumor. It can look innocent, but it is highly invasive. Surgical removal is curative but usually requires removing the tumor as well as a small margin of surrounding gum tissue, teeth and bone. It is best to remove these tumors when they are small.

The most common oral cancer in cats is squamous cell carcinoma, which also occurs in humans. This is a very aggressive cancer, but treatments such as surgery and pain medication help prolong the cat’s life. Some benign inflammatory conditions can resemble squamous cell carcinoma, making a biopsy vital for an accurate diagnosis. For most oral tumors in cats and dogs, we do not know the underlying cause or ways to prevent occurrence. Squamous cell carcinoma in cats is unique in that we know that exposure to cigarette smoke is a strong risk factor.

Clinical Signs of Oral Cancer

The three most common signs of a malignant oral tumor are:

  1. Swelling on the gums or jawbone: The swelling may look like normal gum tissue or be inflamed, bleeding or have a dark discoloration. The swelling can occur on the gums, tongue or roof of the mouth. Sometimes oral tumors are mistaken for a wound or an abscessed tooth because both can lead to swelling or bleeding. Some oral tumors cause teeth to loosen, a clinical sign that mimics periodontal disease. Others manifest themselves as an extraction site that will not heal.
  2. Foul-smelling breath: Bad breath is never normal for a dog or cat, but a tumor can smell like rotten meat because it contains dead tissue.
  3. Reluctance to eat: A dog or cat that used to eat dry food or crunchy treats may refuse to eat anything but soft food. They may take only small bites because it is painful to open their mouths.

Diagnostic Procedures and Treatment Options

If you notice any of these clinical signs in your pet, have your pet examined by a veterinarian immediately. The first step is to get a diagnosis. While some oral tumors have a distinctive appearance, most do not. A biopsy or complete removal of the mass (if it is small enough) is necessary to determine what kind of tumor is present. The biopsy involves removing a piece of tissue and sending it to a laboratory for analysis. Dental radiographs may be used to determine if the tumor involves the bone. Sometimes more than one biopsy is necessary to reach a diagnosis.

If a malignancy is present, metastasisthe development of secondary malignant growths at a distance from a primary site of cancer may be detected by taking X-rays of the chest or using a needle to collect cells from a lymph node. If pets exhibit signs of discomfort, they may require prescribed pain medication and/or antibiotics while waiting for results. Depending on the diagnosis, further surgery or tests like a CT scan are recommended. Complete removal of some oral tumors can result in a cure, so it is important not to delay the process of diagnosis and treatment.

MJ Redman, DVM, is a graduate of Washington State University who lives in San Antonio, Texas. Dr. Redman practices at MissionVet Specialty & Emergency and specializes in veterinary dentistry and oral surgery.