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

Summary In two parallel studies, bitches with mammary tumour received single intralesional injections of BCG (1 mg: 10⁷ living bacteria) and Corybacterium parvum (10⁹ 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.