Chronic radiation-induced proctitis: the 4 % formalin application as non-surgical treatment.

Purpose: Radiation proctitis is a known complication following radiation therapy for pelvic malignancy. The majority of cases are treated nonsurgically. Rectal instillation of formalin solution has been described as a successful treatment for chronic radiation-induced hemorrhagic proctitis resistant to medical treatment. We present our results in patients undergoing treatment with application of 4 % formalin for radiation-induced injury to the rectum.

Methods: All patients were treated under anesthesia by direct application of 4 % formalin solution to the affected rectal areas. Patient gender, initial malignancy, grade of proctitis, need for blood transfusion, previous therapy, number of applications and response to treatment with formalin, complications, and length of follow-up were reviewed.

Results: A total of 15 patients with a mean age of 68.9 (range, 48-77) years were followed for 31.3 (range, 18-51) months. The mean interval from the conclusion of radiotherapy and the onset of symptoms was 6.9 months. The mean duration of hemorrhagic proctitis before formalin application was 7.9 months. Ten patients had only one formalin application and five patients required a second application because of the persistent bleeding. Thirteen patients (87 %) had complete cessation of bleeding. No complications related to the formalin treatment were observed.

Conclusions: According to a revision of the literature and our experience, despite the small number of patients in our trial, we can state that the application of 4 % formalin solution is an effective, safe, and well-tolerated treatment for chronic radiation-induced hemorrhagic proctitis with minimal discomfort and no severe complications.