Veterinarians hate to say: "The biopsy is showing features of a malignancy."
In humans and in pets, malignancy is always a challenge. Malignancy is when a tumor returns at the site of removal or travels to a distant site like the lungs, lymph nodes or the liver.
Mammary cancer in cats is common and often malignant. It is also virtually 100 percent preventable. If cats are spayed before six months of age, we can assure an owner that they do not need to worry about mammary cancer. In cats, the frequency of malignant breast masses is higher than in dogs, whose mammary masses are sometimes benign.
At every physical exam, we check the breast tissue for masses. For kittens born last spring, now is the time to get them spayed before they start their first heat cycle. With cold weather already here, stray and outdoor kittens should be acclimated into a household and have surgery for their own health and to prevent additional pet overpopulation. Speak to your veterinarian if financial concerns would prevent you from having this critical operation. Most veterinarians will make financial accommodations or refer you to an affordable option.
Preventable cancer can take many other forms in our feline friends. One of the first tests we perform on a new cat brought into a household is to check for feline leukemia virus and feline immunosuppressive virus. A simple blood test can be run in the veterinary office or sent to a laboratory.
Blood tests are screened for viruses that can increase a cat's predisposition to cancer, life treating anemia or problems with the immune system. Feline leukemia virus is also contagious between cats, and testing is a critical component of control. Vaccination of young cats is recommended if the kitten will have exposure to outside cats or a large colony of other cats. Although not as common today due to testing and vaccination, feline leukemia virus can be spread from cat to cat by direct contact, by exposure to blood of infected cats and from mother to fetus during pregnancy.
If a cat is ill and the cause is not known, testing for this virus may also be recommended. We can find lymphomas and other malignant cancers in the abdomen or chest associated with feline leukemia virus. Even cats free of this virus can have cancer detected by deep palpation of the abdomen or with imaging like radiographs and ultrasound. Cancer in cats can be treated with surgery, chemotherapy and radiation.
Cats are unusual in their predisposition to start a cancer at the site of any injection and especially with certain vaccinations. Vaccine site sarcoma was first noticed decades ago by pathologists who began seeing an increase in neck tumors after a new killed vaccine was developed. Veterinarians are aware of this issue and take care to use safer vaccines, vaccinate only when necessary, give the vaccine in the leg and monitor for nodules. Now the risk of vaccine-associated sarcoma is much less than the risk of the disease the vaccine is designed to prevent.
At their annual exams, cats are also checked for any oral growths during an examination of their teeth and gums. Cats that are not eating normally should be examined without delay.
Although not a problem here now, sun exposure can cause tumors (squamous cell carcinoma) on the ear tips of cats. Keep cats, especially white cats, from excessive direct sun exposure.
While on the topic of preventable cancers in cats (and dogs), smoking by humans is now linked to cancer in pets. Cats are particularly susceptible to the ingestion of smoke toxins that settle on furniture or carpets. They ingest the carcinogenic smoke toxins from licking their fur. Exposure to smoke has recently been reported to double or triple the incidence of lymphoma seen in cats.
Additionally, oral tumors can be caused from exposure (by grooming) to toxic chemicals. from smoking. Keeping a cleaner environment for your pet's health might just get you to stop smoking.
Lawrence Gerson is a veterinarian and founder of the Point Breeze Veterinary Clinic. His biweekly column is intended to educate pet owners. Consultation with a veterinarian is necessary to diagnose and treat individual pets. If you have a question you'd like addressed in Pet Points, email email@example.com. Please include your name and municipality or neighborhood.