Dog Breast Cancer Prognosis

Dog breast cancer occurs mostly in female dogs who have not been spayed. Spaying your female dog greatly reduces her chances of later developing breast cancer. Breast cancer is a fairly prevalent cancer among dogs, but it usually carries a good prognosis if the cancer is detected and treated while still in its early stages, before it has a chance to spread. Read on to learn more about the symptoms, diagnosis and treatment of dog breast cancer.

Symptoms of Breast Cancer in Dogs

Dog breast cancer typically begins as a tumor, lump or growth in the mammary glands of a female dog. The mammary glands, or teats, may simply appear to be swollen in one or more locations. Dog breast cancer tumors usually feel small and hard beneath the skin. They usually can't be moved around under the skin, and they grow very quickly.

Dog breast cancer is most likely to occur in the fourth and fifth sets of teats, the ones closest to your dog's hindquarters. Mammary tumors can appear in other teats as well, however. 

At least half of dog breast tumors aren't cancerous at all. If your dog's tumor is cancerous, you should see these symptoms, in addition to the presence of a growth or lump in the teat:

  • Cancerous tumors of the mammary gland grow much more rapidly than do benign ones. In four weeks' time, a cancerous tumor is capable of doubling its size.
  • Cancerous tumors are usually uneven in shape, while benign tumors are often smooth and round.
  • Cancerous tumors may cause sores on the skin above them, or may cause bleeding from the skin.
  • Cancerous tumors usually adhere to the surrounding tissue, while benign tumors can be moved about beneath the surface of the skin.

Diagnosing Breast Cancer in Dogs

Though not all mammary tumors in dogs are breast cancer, only your vet can determine if a tumor is cause for concern. Your vet will need to take a biopsy tissue sample for analysis. Surgical removal of the entire tumor may be necessary to make a diagnosis. X-rays can help your vet determine the extent of the cancer's spread, if any.

Dog Breast Cancer Prognosis

Your dog's treatment prognosis will depend largely on the stage of her cancer at the time of diagnosis. Cancers that haven't yet spread to the lymph nodes or other organs can usually be successfully treated.

If your dog's cancer is diagnosed before it spreads, surgical removal of tumors can often effectively treat the cancer. Your vet will need to remove quite a bit of healthy tissue as well, to help keep the tumors from coming back. If your dog hasn't been spayed yet, your vet may recommend spaying to help prevent breast cancer's recurrence. 

If your dog's cancer has already spread, the prognosis may be very poor. Chemotherapy or radiation therapy, however, can help extend your dog's life and relieve her symptoms.

You can prevent dog breast cancer by spaying your female dog. Dogs spayed before their first heat cycle are least likely to get breast cancer. Spaying after the first heat cycle still leaves your dog at some risk for breast cancer, but the risk is still significantly reduced.