Epidemiological features of feline mammary carcinoma.

An epidemiological survey involving 132 cats with mammary neoplasia, seen at 15 North American veterinary medical teaching hospitals, was conducted. The ratio of malignant to benign tumours was 9:1. There were 113 cases of carcinomas of all types (including two males), with adenocarcinoma being the predominant cell-type. Relative risk analysis indicated that the Siamese breed had twice the risk (P less than 0.01) of developing mammary carcinoma compared to all breeds combined. The age at diagnosis in Siamese females tended to be younger than in other breeds. Comparison of clinical and pathological features of breast cancer suggests that the cat is an appropriate surrogate for the experimental study of human breast cancer. The apparent lack of oestrogen dependency in feline breast cancer also suggests that the cat may be especially suited for evaluating therapeutic regimens for breast cancers that do not respond to hormonal manipulation.