Mammary Tumors in Dogs

Mammary tumors are common cancerous nodules that mostly affect unspayed female dogs. If the dog is spayed in later years, there is still a chance for mammary tumor development, but the chances are greatly decreased. For this reason, a dog that is not intended for breeding should be spayed before the age of two years. Development of mammary tumors may be minor or aggressive; early detection of the cancer is imperative for recovery.

  1. Types

    • Mammary tumors in dogs may be benign or malignant. The cell growth for this type of cancer is usually made from multiple cell sources. Although the condition is rare, the cells stem from glandular and connective tissue. Cellular growth at this level is a type of benign tumor. Several malignant tumors can develop in mammary tissue including tubular adenocarcinomas, papillary adenocarcinomas and osteosarcomas. Malignant tumors are dangerous if not detected early. These cells enter the bloodstream and metastasize to other tissue, growing out of control and damaging organs.

    Detection

    • Female dogs have mammary glands that vertically span the length of the abdomen. There are five glands on each side of the dog. Early detection of mammary tumors are small nodules that form around the gland. Although it can happen on any one of them, the most common area is the fourth and fifth gland, which are the two closest to the anus.

    Symptoms

    • Symptoms differ between benign and malignant tumors. The pet owner can detect tumors by feeling the mammary glands. However, confirmation of the type of tumor requires a biopsy from a veterinarian. Benign tumors are small, smooth nodules that grow slowly. Malignant tumors are fast-growing, hard attachments on the skin. Malignant tumors also cause bleeding and ulcerations in the skin.

    Treatment

    • Malignant tumors are surgically removed with possible followup of radiation and chemotherapy. Malignant tumors are removed with surrounding tissue to ensure that all the cancerous tumor cells are removed. Radiation and chemotherapy are not commonly used, although use of subsequent treatment depends on the veterinarian practices.

    Prevention

    • The best prevention of mammary tumors is spaying the dog prior to its first heat. Dogs spayed after the first heat have a higher chance of mammary tumor development, but the chances are still small provided the owner schedules the procedure prior to two years of the dog's age.