Radiation therapy for carcinoma of the prostate: the experience with small intestine injury

Between 1975 and 1977, 74 patients had roentgenographic studies of the small intestine to determine the anatomic relationship of the small intestine to the pelvic portal and to the booster portal. Digital examination, contrast cystography and ultrasound B scans were used to delineate the prostate carcinoma. The small intestine was observed to be at the level of the superior extent of the prostate carcinoma in 19 patients and overlapped the prostate carcinoma in 10 patients. Booster portal size was determined by consideration for tumor control, cure and complication. Therapeutic efforts to reduce tumor size prior to booster irradiation included hormone therapy and whole pelvic irradiation. A “shrinking” field could then be used in patients at risk for small intestine injury. Recognition of the relative position of the terminal Ileum to the pelvic portal was important for patients who undergo surgery after irradiation. Inadvertent injury can be avoided. Since initiation of this study no patient has developed small intestine injury. Tumor control rates remain constant.