Late radiation injury of the gastrointestinal tract

Abstract

Radiotherapy plays an important role in the primary or postoperative curative treatment of several tumors, e.g. gynecological malignancies, prostate cancer and rectal carcinoma. Diarrhea is a well-known side-effect of radiotherapy, both during and after irradiation. Symptoms of acute radiation enteritis, such as abdominal crampy pain, blood loss and diarrhea, are due to mucosal injury. Similar symptoms may develop with an interval of more than a year after radiotherapy. The mechanism of this late radiation damage, however, is quite different, with damage of the endothelial cells of small blood vessels including microthrombi, thickening of vessel walls and focal infarctions leading to local hypoxia. Chronic diarrhea is common and sometimes disabling; up to 46% of patients may be discontent with their bowel habits for most of the time1,2. Fortunately, severe late radiation injury of the gastrointestinal (GI) tract requiring surgery is relatively rare ((overall incidence 5–10%). Symptoms usually develop within 2 years after radiotherapy but the interval may be as long as 20 years. Although the proximal part of the GI tract is more sensitive to radiation injury, due to a high cell turnover rate, the colon and rectum are affected most often, followed by the distal segment of the ileum. This is mainly due to the high incidence of gynecological tumors, a large proportion of which are treated with radiotherapy and have an excellent prognosis; the fact that most patients are women is also related to this circumstance. It is important to keep in mind that clinical manifestations of late radiation injury are usually aspecific (malaise, anorexia, weight loss, abdominal discomfort) and may closely resemble (recurrent) malignancy.