Introduction
Cancer is defined as any malignant, cellular tumor. To understand this definition, we must break it down. A “tumor” is defined as a swelling or other new growth of tissue in which there is uncontrolled and progressive cell multiplication. Tumors can be benign or malignant. “Malignancy” is defined as the tendency to progressively worsen and to result in death, usually accompanied by properties of invasiveness and metastasis. “Metastasis” refers to the transfer of disease from one part of the body to another part that is not directly connected with it – essentially, a migration of cells into neighboring or remote tissues. Putting these definitions together, the term “cancer” encompasses a group of diseases that involve an uncontrolled and progressive transformation of normal cells into abnormal ones that become invasive, progressively worsen and ultimately spread. Another word for cancer is “neoplasia,” which is defined as the formation of any new and abnormal growth, especially one in which cell multiplication is uncontrolled and progressive.
How Cancer Affects Dogs
Cancer is one of the leading causes of death in dogs, especially older dogs, which is partially due to the fact that companion animals are living longer with continual improvements in nutrition and veterinary care. How cancer affects a particular animal depends upon the type of cancer and the biological make-up of the individual dog. Meaningful generalizations about the effects of cancer cannot be made. Ultimately, however, most untreated or untreatable malignancies will cause or hasten death.
Causes of Cancer in Dogs
Medical science has not yet discovered the precise causes of the various types of cancer, despite intense research in both the animal and human realms. Many different cancers occur in dogs. These include lymphosarcoma, osteosarcoma, soft tissue sarcomas, mast cell tumors, hemangiosarcoma, oral melanoma and mammary neoplasia, among many others. Each of these can present in multiple ways, with varying frequencies and degrees of severity. Some dog breeds are predisposed to developing certain types of cancers. Spaying or neutering can reduce the risk of testicular and mammary gland neoplasia.
Prevention of Cancer
Little is known about how to prevent cancer in companion animals. Once the underlying causes of the various cancers are ascertained, prevention will become more plausible.
Special Notes
Early diagnosis of cancer always improves the prognosis. Surgery, radiation and chemotherapy are available at specialized veterinary hospitals to treat canine cancer. With prompt diagnosis, aggressive treatment and ongoing management, including pain management and dietary support, many dogs with cancer go on to live long, confortable and relatively normal lives.