We recommend that all mammary gland masses are surgically removed and biopsied to determine the tumor type. Hormonal therapy in the form of ovariohysterectomy may be beneficial in unspayed dogs with carcinomas or adenocarcinomas. A recent study at the Veterinary Hospital of the University of Pennsylvania showed that dogs spayed either at the same time of their tumor removal or within two years prior to the tumor surgery lived significantly longer than dogs that remained unspayed after their tumors were removed. Chemotherapy may also be indicated in dogs with aggressive tumors. Chemotherapy has been shown to be effective in individual dogs with metastatic adenocarcinomas, but there are no large studies that prove the benefit of chemotherapy in dogs suspected of being at risk for metastasis.
Owners can play an important role in their dog's health.
The protective effect of early ovariohysterectomy is substantial, and dogs that are not intended for breeding should be spayed before their first or second heat. Obesity and a high fat diet in the first year may also increase the risk for tumor development, so not overfeeding young growing dogs could be beneficial. Owners should examine their dogs at regular intervals for any lumps, bumps, or swellings and take them for yearly veterinary checkups. All lumps should be surgically removed and biopsied. Early diagnosis and treatment are crucial for a good outcome.