Anorectal cancer following topical formalin application for haemorrhagic radiation proctitis

Topical formalin has been used as an effective treatment for haemorrhagic radiation proctitis. In the course of reviewing our experience with this modality, we identified two patients who developed anorectal cancer during the follow-up period.

From 2001 to 2005, 49 patients who received pelvic radiation for treatment of prostate, rectal or endometrial cancer subsequently developed haemorrhagic radiation proctitis. Four percent formalin was applied in the office setting under direct visualization with a rigid proctoscope and without sedation. Response to treatment was then reviewed.

Seventy-eight per cent of patients reported a complete response to formalin application. Only 14% were refractory to formalin treatment. Two patients subsequently presented with anorectal cancer.

Topical formalin application in the outpatient setting appears to be an effective first-line treatment for haemorrhagic radiation proctitis. We report the first cases of anorectal cancer which developed subsequent to formalin application. Pelvic irradiation is known to increase the risk of developing a second malignancy, therefore it is impossible to determine what, if any, role formalin application played in the development of the second malignancies.