Immunity in Colonic Tumor Patients after Operation

THE PROGRESSION O[ a mal ignant tumor depends upon the inherent characteristics of the tumor and the response of the host. T h e latter is now thought to depend on an immunologic mechanism that many surgeons believe may be adversely altered by extensive ablative surgery or radiotherapy. These surgeons have shown that their more conservative surgical approach has not been to the detr iment of patient survival and has reduced surgical morbidity. These observations have mainly been concerned with carcinoma of the breast,S, 8 but many colorectal surgeons are now considering suitable rectal tumors for local excision, Is and some, in association with radiotherapists, I2 are using local irradiation. The immune response of the individual to his tumor is mediated by lymphocytes, which mature either as bone marrowderived cells capable of producing humoral antibodies or as thymus-processed cells capable of init iat ing cell-mediated graft or