Intrarectal formalin treatment for haemorrhagic radiation-induced proctopathy: efficacy and safety.

Aim: Pelvic radiotherapy is limited by dose-dependent toxicity to surrounding organs. The aim of this prospective study was to evaluate the efficacy and safety of intrarectal formalin treatment for radiotherapy-induced haemorrhagic proctopathy (RHP) at the Royal Marsden Hospital.

Method: Adult patients were enrolled. Haemoglobin was evaluated before and after formalin treatment. Antiplatelet and/or anticoagulation treatment and administration of transfusion were recorded. The interval between completion of radiotherapy and the first intrarectal 5% formalin treatment was assessed and the dose of radiotherapy was evaluated. Clinical assessment of the frequency and amount of rectal bleeding (rectal bleeding score 1-6) and endoscopic appearance (grade 0-3) were classified. Complications were recorded.

Results: Nineteen patients were enrolled, comprising 13 men (68%) and 6 women. The mean age was 75 ± 9 years. The median time between completion of radiotherapy and the first treatment was 20 months [interquartile range (IQR) 15 months] and the median dose of radiotherapy was 68 Gy (IQR 14 Gy). Thirty-two procedures were performed (average 1.7 per patient). In total, 9/19 (47%) patients were receiving anticoagulation and/or antiplatelet medication and 5/19 (26%) received transfusion prior to treatment. The mean value of serum haemoglobin before the first treatment was 110 ± 18 g/L and afterwards it was 123 ± 16 g/L (p = 0.022). The median rectal bleeding score before the first treatment was 6 (IQR 0) and afterwards 2 (IQR 1-4; p < 0.001), while the median endoscopy score on the day of first treatment was 3 (IQR 0) compared with 1 (IQR 1-2) on the day of the last treatment 1 (p < 0.001). One female patient with a persistent rectal ulcer that eventually healed (18 months of healing) subsequently developed rectovaginal fistula (complication rate 1/19, 5%).

Conclusions: Treatment with intrarectal formalin in RHP is effective and safe.