Some epidemiological aspects of mammary neoplasia in the bitch
Else, R.W.; Hannant, D.
Veterinary Record 104(14): 296-304
1979
ISSN/ISBN: 0042-4900 PMID: 575967 Document Number: 147549
Of 226 cases of mammary tumours studied over 36 months, 88 were benign simple, 66 benign mixed, 164 simple carcinomas, 59 complex carcinomas and 15 sarcomas; some animals had more than one tumour. The bitches were 8-13 years old. No differences could be demonstrated in age distribution of the different types or in breed distribution. Both benign and malignant tumours increased in frequency from anterior to posterior glands. 23 bitches had been spayed, but only 3 at 2 years of age; 42% were parous and 35% had a history of pseudopregnancy. Where pseudopregnancy had been recorded there was increased chance of the tumour being malignant. In follow-up studies there were 68 tumour recurrences of the same type at the same site in 44 of them. Of 36 bitches with carcinomas, 30 had recurrences within six months of first removal and all with sarcomas had recurrence within three months. New tumours, usually of the same type, developed in 26 bitches. Cumulative percentage mortality curves for benign tumours were parallel with mortalities from all causes, but this was not so for malignant cases. Median survival times following surgery were 12 and 6 months for benign tumours and 4, 3 and 3 months for malignant tumours. Distribution of metastases in tumour type is recorded.