Measures to minimize small intestine injury in the irradiated pelvis

Small intestine injury causes long-term suffering and high mortality. Five of 187 of our patients had developed serious small intestine injury. Four patients had corrective surgery. Three patients died. All were women. Subsequently, all patients who received definitive pelvic irradiation had small intestine roentgenograms to determine its location and mobility. Female patients, thin patients, and elderly patients had larger amounts of small intestine in the whole pelvis, a deeper cul de sac, and a greater incidence of relatively immobile small intestine. Patients with relatively immobile small intestine in the treatment field may be predisposed to injury. There was no relationship of the incidence of relatively immobile small intestine to prior pelvic surgery. We used the findings from the small intestine roentgenograms to modify individually the radiotherapy regimen so as to minimize the risk for small intestine injury. Patients were placed in the prone position to displace the small intestine out of the treatment fields used for booster dose irradiation. The treatment field was modified to exclude the small intestine. The total tumor dose delivered was determined by expectations for cure vs complications. To date, none of the patients in this study group has developed small intestine injury. Cadaver studies showed the feasibility of elective shortening of the pelvic cul de sac. The small intestine can be displaced away from the bladder, prostate, or cervix. (U.S.)