Background:  Several treatments have been described for hemorrhagic radiation proctitis. The treatment outcomes are variable. Colonic irrigation and oral antibiotics for hemorrhagic radiation proctitis have bee recently reported to be a novel and promising therapeu approach. However, a comparative study of this treatment has never been investigated.

Objective:  This study aimed to compare colonic irrigation and oral antibiotics (irrigation group) versus 4% formalin application (formalin group) for treatment of hemorrhagic radiation proctitis.

Design:  This was a randomized controlled trial.

Setting:  This study was conducted in a tertiary care/university-based hospital.

Patients:  Fifty patients with hemorrhagic radiation proctitis were randomly assigned to each treatment group (n = 25).

Interventions:  For individuals allocated to the irrigation group, daily self-administered colonic irrigation with 1 L of tap water and a 1-week period of oral antibiotics (ciprofloxacin and metronidazole) were prescribed. For individuals allocated to the formalin group, 4% formalin application for 3 minutes was performed.

Main Outcome Measures:  Patients’ symptoms and the endoscopic findings of each group were collected. Patient satisfaction was surveyed. The outcomes were evaluated at 8 weeks after the initiation of treatment.

Results:  There was a significant improvement in rectal bleeding and bowel frequency in both treatment groups, but significant improvement in urgency, diarrhea, and tenesmus was demonstrated only in the irrigation group. The comparative study between 2 treatments revealed greater improvement in rectal bleeding, urgency, and diarrhea in the irrigation group. Twenty of 24 patients in the irrigation group and 10 of 23 patients in the formalin group were satisfied with the treatment.

Limitations:  This trial cannot illustrate whether the antibiotics and the irrigation were equally important because of the limitation of a 2-armed design.

Conclusions:  The treatment with colonic irrigation and oral antibiotics appears to be more effective than 4% formalin application for hemorrhagic radiation proctitis treatment and achieves higher patient satisfaction.