The first sign of the tumor is a small hard lump in the mammary tissue. These can often go unnoticed until they reach a significant size. Most feline adenocarcinomas tend to first spread to local lymph nodes (glands) or adjacent mammary tissues rather than other parts of the body making recurrences common after surgery. Early removal of tumors however can still greatly influence the survival times of effected cats.

There are three surgical methods of dealing with a mass in the mammary tissue. 1- Removal of the tumor from the mammary tissue. 2- Removal of the gland containing the tumor (mastectomy). 3 Removal of all the mammary glands on the side of the body effected (radical mastectomy). The logic behind a radical mastectomy is to remove all of the lymph glands which drain the site of the tumor and all areas of potential local spread.

Chemotherapy has been advocated as an additional treatment as adenocarcinomas respond well to a number of drug combination.

Desexing of females before their first heat period does not appear to have an influence over the development of mammary tumors in cats