Cancer is a terrifying word. Most people have been affected by the disease in one way or another. Unfortunately, cancer isn’t limited to our human family members. It is also possible to find cancer in cats. According to Cornell University of Veterinary Medicine, about 2% of pet cats (of which there are 70 – 80 million in the US ) will develop cancer and this number just keeps going up.
What is Cancer?
A cat’s body is made up of cells. Each cell has a set of DNA that regulates how the cell functions and how it multiplies. A normal, healthy cell multiplies by copying its DNA and separating into 2 identical cells (a process called mitosis). Normal cells do not copy themselves infinitely. Eventually, the instructions inside the cell’s DNA will tell the cell that it is time to finish its life cycle and the cell dies. The speed at which a cell copies itself is controlled by its own internal instruction set, availability of space, and through communication with surrounding cells.
Mutations can occur in the DNA of a cell. What causes the mutations in the DNA of a cell that results in cancer in cats is largely unknown. Often these mutations are caught and fixed by structures within the nucleus of the cells or the entire cell is removed from the body by the immune system. However, ocassionally these mutations go unchecked. The mutated cells begin to replicate out of control. They outgrow their allotted space (tumors) and disrupt the function of the organs of which they are a part.
The cells that multiply uncontrollably are cancer. If the cancerous cells stay in one spot, the tumor is considered benign. However, if the cancerous cells break off of the original tumor and move throughout the body to form cancerous legions elsewhere, the tumor is considered malignant.
The Most Common Cancers in Cats
Cancer in cats is very complicated. It is not a singular disease, but rather a large set of diseases. The type of cancer is determined by the location of the cancerous cells in the body and the types mutations that exist within the DNA. There can be more than one type of cancer present in a single tumor. The 3 most common types of cancer in cats are (most statistics from The Veterinary Cancer Center):
This type of cancer in cats accounts for 1/3 of all malignant tumors. Tumors often occur in the gastrointestinal tract, chest cavity, kidneys, and the spleen. Most commonly it is caused by the viruses which cause FeLV and FIV and by second-hand smoke. Lymphoma is not considered to be curable. Prognosis depends heavily on the location of the tumor, the type of treatment used, and the stage of cancer. Even with treatment only 25-30% of cats with Gastrointestinal Lymphoma will achieve complete remission.
- Squamous Cell Cancer
Squamous cell cancer covers 3 different types of cancer in cats: Oral Squamous Cell Cancer, Cutaneous (skin) Squamous Cell Cancer, and Bowen’s Disease. Factors that increase the risk for these types of cancer are second-hand smoke, over exposure to sunlight, a weakened immune system, and exposure to the papillomavirus. White/light colored cats are most at risk for Cutaneous Squamous Cell Cancer. If caught early, the prognosis for these types of cancer is good. However, in the case of Oral Squamous Cell Cancer, the average length of survival without treatment is only 3 months.
- Mammary Gland Cancer (Breast Cancer)
Mammary Gland Cancer is responsible for 20% of cancer in cats that are female. An astounding 85% of mammary gland tumors are malignant. It is believed that this type of cancer in cats is caused by hormonal issues. Siamese cats are at the highest risk of developing this cancer. Spaying a cat can reduce their risk of developing breast cancer by 40-60%! With treatment, the average survival range varies widely from 4 months to 3 years.
Treatments for cancer in cats vary based on the type of cancer, stage of cancer, and effect of the treatment on the cat’s quality of life. For cats, treatments use a much lower doses of medication for longer periods of time than in human treatments. There are 3 basic treatments:
Surgery is used in cases where a tumor can be removed from the body successfully.
- Radiation Therapy
Radiation therapy kills cells in a very targeted manner. It’s uses include rapid pain relief, reduction of tumors, and the slowing of tumor growth.
Chemotherapy works throughout the entire body interrupting the ability of cells to replicate. Unlike in humans, chemotherapy is well tolerated by cats and they typically do not experience hair loss.
The Silver Lining
The good news is that as the science for curing human cancers progresses, the science for treating cancer in cats gets better as well. Better forms and combinations of radiation and chemotherapy are beginning to show up. Screenings and tests are also getting better. Natural, holistic treatments are being proven helpful. Acupuncture has been shown to help in several ways including pain management appetite stimulation, and control of nausea.
Education on cancer in cats is very important. The knowledge about cancer in cats lags behind that of dogs because people have not cared for cats in the same way they did for dogs in the past. There may not be any cures yet, but early detection can do wonders and a few causes can be avoided.
Have you known someone with a pet that had cancer?
Hope; Defeating the Common Causes of Death in Cats Series
This is the second of a series of 4 posts addressing a few of the most common causes of death in cats. The intent of the series is to educate cat owners and lovers about each cause of death and discuss the solutions that exist (or lack thereof).
Sources & Digging Deeper