The role of endoscopic evaluation for radiation proctitis in patients receiving intermediate-dose postoperative radiotherapy for rectal cancer

High-dose pelvic radiotherapy (RT) is known to be associated with chronic radiation proctitis (RP). However, the effects of intermediate radiation doses are unknown. We assessed the incidence of late clinical RP among patients with rectal cancer receiving intermediate-dose postoperative RT, as well as the role of early endoscopic abnormalities in predicting RP development. We retrospectively reviewed 153 patients with rectal cancer who received postoperative RT at a median dose of 54 Gy between 2005 and 2009 and who underwent endoscopic examination within 12 months thereafter. Endoscopic RP was assessed using the Vienna rectoscopy score (VRS). Late clinical RP toxicity was evaluated, as was its correlation with endoscopic RP. All patients underwent an endoscopic examination at a median of 9 months after postoperative pelvic RT. Endoscopic RP was detected in 45 patients (29.4%); the predominant patterns were telangiectasia and congested mucosa. During the median 88-month follow-up period, 29 patients (19.0%) experienced late clinical RP; only 3 (2.0%) had Grade 3 or above. The VRS predicted the development of late clinical RP as well as its cumulative incidence (P < 0.001). Endoscopic evidence of telangiectasia was significantly associated with the development of late clinical RP (P < 0.001). Early endoscopic findings using VRS are useful for predicting the possibility of late clinical RP, although the incidences of severe cases were low. Patients with endoscopic abnormalities should be followed closely owing to their susceptibility to clinical RP.