Formalin Application in the Treatment of Chronic Radiation-Induced Hemorrhagic Proctitis—An Effective But Not Risk-Free Procedure: A Prospective Study of 33 Patients

This prospective study evaluated the efficacy and safety of local formalin application in chronic refractory radiation-induced hemorrhagic proctitis.

All patients were treated under anesthesia by direct application of 4 percent formalin to the affected rectal areas.

The study included 33 patients (17 women) and was conducted between January 1994 and December 2001. There were 11 anal cancers (33 percent), 11 prostate cancers, 9 cervical or endometrial cancers, 1 bladder cancer, and 1 rectal cancer. The mean number of daily rectal bleeds was 2.7 (range, 0.5–15). Nineteen patients (58 percent) were blood transfusion dependent. Twenty-three patients had only one formalin application and 10 patients required a second application because of the persistent bleeding. The treatment was effective in 23 cases (70 percent): 13 patients had complete cessation of bleeding and 10 patients had only minor bleeding. Six anal or rectal strictures occurred: 4 patients had been treated for anal cancer (36 percent) and 2 patients had been treated for other cancers (9 percent). None of the strictures was malignant. Anal incontinence worsened in 5 patients of the 11 who had been treated for anal cancer (45 percent) and occurred in 4 of the 22 other patients (18 percent).

Formalin application is an effective treatment for chronic radiation-induced hemorrhagic proctitis. However, local morbidity is not negligible. This result may be related to the high proportion of anal cancers in the series. In our opinion, therefore, formalin application should be reserved for severe hemorrhagic proctitis refractory to medical treatment and should be thoroughly discussed in cases of anorectal radiation-induced stricture, prior anal incontinence, or treated anal cancer.