Topical phenylephrine in the treatment of radiation-induced faecal incontinence

Acute bowel toxicity after pelvic radiotherapy is defined as occurring within 3 months of the start of treatment; chronic gastrointestinal toxicity may continue after the acute phase or start after a latent period. One in five patients develop chronic faecal incontinence affecting quality of life; how best to treat these patients is not known. This retrospective study aimed to determine the effects of a new agent, phenylephrine gel, in the treatment of chronic radiation-induced faecal incontinence.

Patients prescribed phenylephrine gel for new-onset faecal incontinence after radiotherapy were identified from our database of patients treated in a specialist radiation-induced bowel damage clinic since 2000. Changes in the level of faecal incontinence were assessed using the Vaizey faecal incontinence scoring system before and after treatment.

Fifteen patients (nine men and six women) of mean age 70.5 years (standard deviation 8.2, age range 56-82 years) were treated with phenylephrine gel a median of 43 months after completing radiotherapy. The median Vaizey score before treatment with phenylephrine gel was 17 (interquartile range [IQR] 14-20) and after treatment was 14 (IQR 11-18) (P = 0.005). The median length of treatment with phenylephrine gel was 28 days (IQR 28-365). Scores improved in 11 out of 15 patients; four out of 15 patients showed substantial improvements of 7 or more points; and seven patients considered the gel helpful.

Topical phenylephrine gel for the treatment of radiation-induced faecal incontinence has not been previously reported. This small, retrospective study suggests that it may help most patients and, in some, the improvement may be substantial. However, larger placebo-controlled prospective studies are required.