Dog breast cancer is common among middle-aged, unspayed dogs, but can also be acquired by males or spayed females. However, risk is dramatically reduced for females spayed before the age of 2.
Symptoms of Breast Cancer
Breast cancer usually appears as a lump or multiple swellings in the mammary glands, located along your dog's stomach, each with its own nipple. Tumors can usually be felt when inspecting your dog for lumps as long as you run your hands along her stomach. The lumps usually feel like large pieces of gravel under the skin, very hard and difficult to move, and they grow quickly, doubling in size monthly.
About half of tumors that appear in your dog's mammary glands are benign. The other half are malignant. It's often easy to tell the difference when feeling them because benign tumors are usually smooth, round and slow-growing. Malignant tumors often grow much more rapidly and exhibit abnormal shape, firm attachment to skin and possible bleeding or ulceration.
If detected early enough, there are few secondary symptoms; however, with all types of cancer, there is a risk of spreading to other tissues, which would cause additional symptoms depending on where it spreads. The best way to prevent this is regular wellness checks to identify new lumps that appear on your dog.
However, you can't be sure if the tumor is malignant without a veterinarian biopsy. This can be done with a thin aspirator needle or removal and study of the entire tumor.
Treatment of Breast Cancer
Radiation and chemotherapy have not been widely used or researched for canine breast cancer. Radiation may be used occasionally to ensure removal of the tumors and chemotherapy to ensure that it hasn't spread, but surgery is the most commonly used treatment.
If detected early, the tumors can generally be removed easily since they are so close to the skin. Often, this will require removal of all mammary glands, which is not as serious in dogs as a mastectomy in humans. Dogs usually return to full activity around two weeks after surgery. If the dog has not yet been spayed, many veterinarians will also spay the dog to reduce future occurrence.
In older dogs, surgery is not always recommended.
Prevention of Breast Cancer
Most occurrences of breast cancer can be easily prevented by spaying your female dog. A dog that is spayed before her first heat has a .05 percent chance of contracting breast cancer. After the first heat, the risk increases to 8 percent and after the second heat to 26 percent. Thus, early spay is the most important piece of prevention.
Risk of spreading can be decreased significantly with early detection so identify how your dog's mammary glands feel when they are normal and check regularly for new lumps.
While breast cancer is a serious illness, risk can be greatly reduced with prevention and can be treated easily with early detection. Be aware of changes to your dog's mammary glands and immediately consult your veterinarian should you notice a lump.