Treatment and Prognosis of Cancer in Dogs
Goals of Treating Cancer
The goals of treating cancer are to prevent further metastasis (spreading), remove all cancerous tissue when possible and restore the dog’s quality of life. When an owner notices a lump or bump on his dog or otherwise perceives that his dog just “isn’t doing right,” he should take his pet to the veterinarian as soon as possible.
Surgery is the treatment of choice for many canine cancers. Localized masses often can be surgically removed and, when detected early, the procedure carries an excellent success rate. Upon removal, the veterinarian will evaluate whether (and if so, how aggressively) the cancer has spread to other organs in the dog's body. The veterinarian will use this information to assess the outlook for the animal and to establish a prospective course of action. The removed tissue will be submitted to a pathology laboratory for determination of the exact type of tumor and whether appropriate surgical margins were obtained when it was removed. When a cancerous mass is removed, the surgeon tries to achieve what are called “clean surgical margins.” This means that normal, non-cancerous tissue can be seen microscopically and continuously at all edges of the removed tumor.
In cases where the cancer is inoperable, other treatment options may be available, including radiation, chemotherapy and other biological therapies. Radiation therapy is designed to kill malignant cancer cells by exposing them to high levels of deadly radiation. Similarly, chemotherapy (treatment with drugs) is a way to kill cancer cells, although it usually cannot target specific cells, but rather targets all rapidly-dividing cells in the body. In some cases, veterinarians may use a combination of therapies, such as surgery together with radiation and/or chemotherapy. One of the adverse effects of both radiation and chemotherapy is that many normal cells can be damaged or destroyed by the treatments. Other existing and emerging treatment options for animals with cancer include targeted molecular therapy, immunotherapy, hyperthermia, cryotherapy, phototherapy, photochemotherapy, thermochemotherapy and emerging unconventional or alternative therapies.
Other less traditional techniques that may benefit dogs with cancer, in addition to medical treatment, might include: massage therapy to help reduce pain, overall stress, and improve comfort; possible application of acupuncture and/or acupressure techniques; use of herbal or other non-regulated supplements or homeopathic “remedies”; and other forms of supportive care that may help to ease pain, increase circulation, speed healing and otherwise promote wellness, relaxation and comfort. Some of these adjunct approaches lack controlled studies of their effectiveness and may not have established quality control methods or ways to assess their benefit to dogs with cancer. However, they may be worth discussing with a veterinarian as an add-along to medical therapy.
The goal of any treatment for cancer, of course, is to eliminate only the malignant cells, but it is not presently possible to completely isolate healthy tissue from cancerous tissue during these treatments. Owners can expect to see some side effects in their dogs from both radiation and chemotherapy, including possible nausea, vomiting, diarrhea, weakness, lethargy and lack of appetite.
The prognosis for dogs with cancer is highly variable, depending upon the type of cancer involved, the location of the tumor(s), whether the cancer is malignant and/or has metastasized, whether the disease was caught early or late in its progress, the commitment and financial status of the owner and the body condition, appetite, activity level and overall health of the animal. Thankfully, modern cancer management in domestic dogs goes well beyond mere attempts to remove cancer cells. Nutritional support, pain management, ulcer prevention, gastric protectants, physical therapy, alternative therapies and a number of other supportive techniques can all be key components of managing canine cancer. It is not uncommon for owners of dogs with cancer to spend $2,000 to $10,000 or more on treatment. Owners are entitled to be given all available treatment options regardless of their cost, so that they can make the best decision for their dog given their personal circumstances.