The incidence of severe chronic ileitis after abdominal and/or pelvic external irradiation with high energy photon beams.

The authors report a 7.9% incidence of late severe ileal complications after abdominal and/or pelvic external radiation therapy in 188 consecutive patients. All treatments were performed using 25 MV photon beams, with AP-PA field technique, a daily dose of 1.8-2 Gy, 5 times a week. One hundred and two (54.3%) patients were given whole pelvic irradiation up to 45-55 Gy without a boost, 64 patients (34%) received boost doses on limited volumes up to 60-65 Gy. The analysis of factors which could be useful in predicting a high risk of severe ileal sequellae, has shown that the main factor was the past history of previous laparotomy. Thus, the incidence of chronic ileitis in patients who have never been laparotomized in the past and who were treated by radiotherapy alone, was 2.2% (2/97); in contrast patients with previous abdominal surgery whatever its purpose, showed in 13/91 cases (14.3%) severe ileal complications (p less than 0.05). In addition, the risk of chronic ileitis increases with the number of previous laparotomies irrespective of delay or purpose: 10.1% after one laparotomy, 22.2% after two and 50% after three or more laparotomies. The influence of these data on the planning of abdominal and/or pelvic external irradiation is discussed.