Intratumoral BCG and Corynebacterium parvum therapy of canine mammary tumours before radical mastectomy.

In two parallel studies, bitches with mammary tumour received single intralesional injections of BCG (1 mg: 10(7) living bacteria) and Corybacterium parvum (10(9) killed bacteria) (53 bitches) or C. parvum alone (129 bitches) at the same dosage. Control groups received injections, following the same protocol, of 1 ml BCG suspension medium diluted in saline in the first study (51 bitches) or no injections at all (120 bitches in the second study). A block dissection, including mammary tumours, adjacent mammary glands, and regional lymph nodes, was performed 2 weeks later in all animals. On the basis of histologically confirmed malignant tumours, 48 bitches (25 treated by-immunotherapy and 23 controls) in the first study and 67 bitches (30 treated by immunotherapy and 37 controls) in the second study remained for postsurgical follow-up. The clinical tolerance of the treatment was generally good. No significant differences were found in cumulative survival rates between treated and control group in either studies.