Formalin instillation for refractory radiation-induced hemorrhagic proctitis. Report of 16 patients

Our goal was to evaluate use of topical (4 percent) formalin in management of radiation-induced hemorrhagic proctitis, refractory to other methods of treatment. Specifically, we wished to determine its safety, ability to stop bleeding, and complications associated with therapy.

Sixteen patients with radiation-induced hemorrhagic proctitis were treated with topical (4 percent) formalin. All had been previously treated with conservative regimens such as cautery, topical steroids, or laser, but these had failed. Five-hundred milliliters (ml) of a 4 percent formalin solution was instilled into the rectum in 50-ml aliquots. Each aliquot was kept in contact with rectal mucosa for approximately 30 seconds. Treatments were performed under local anesthesia in nine patients, sedation only in four, spinal in two, and general in one patient.

In 12 patients, bleeding stopped after a single formalin instillation; in 3, bleeding was considerably reduced but continued sporadically. One patient required three treatments before bleeding stopped. Four patients developed postoperative anal pain, of which one also had significant tenesmus and reduced capacity. Of these four patients, only two had significant anal pain and fissures that lasted longer than one month.

Topical (4 percent) formalin is safe and effective in treatment of radiation-induced hemorrhagic proctitis. A single treatment will stop bleeding in 75 percent of patients.