Purpose: The purpose of this study was to review our results in patients undergoing treatment with 4 percent formalin for radiation-induced injury to the rectum.
Methods: A retrospective review of office charts was performed, identifying all patients undergoing formalin treatment. Patient gender, initial malignancy, prior treatments, response to treatment with formalin, complications, and length of follow-up were reviewed. All patients had flexible endoscopy to assess for proximal sources of bleeding. The indication for treatment was a symptomatic patient with endoscopic evidence of radiation injury. A cotton pledget was used for direct application of 4 percent formalin to the affected area via a rigid proctoscope or anoscope. The treatment was repeated if blanching did not occur or if bleeding continued. Patients were followed up at three-week to four-week intervals and treatment was repeated based on the above indications. Treatments were continued until cessation of bleeding occurred or, when treatment failed, operative treatment was required.
Results: Thirty-six patients were identified. Three were lost to follow-up. Symptoms included bleeding in all but one patient, who presented with an ulcer. There were 33 (26 male) patients. Seventeen (51.5 percent) patients had prior treatment. The number of formalin treatments ranged from 1 to 13, with a mean of 3.4. The follow-up ranged from 1 to 60 months, with a mean of 18 months. Twenty-nine (88 percent) patients had improvement or cessation of symptoms. Four (12 percent) patients failed treatment. Two patients were noted to have full-thickness ulcers and both failed formalin treatment. No complications were noted related to formalin treatment.
Conclusion: We conclude that formalin therapy is a safe and effective form of treatment that can be performed in the office with minimal discomfort and no complications. It can be performed multiple times until results are achieved. Formalin therapy may be useful as a first-line treatment for chronic radiation proctitis, however, a prospective controlled trial comparing modalities is required to prove this to be true.