Is prostate cancer radiotherapy using implantable rectum spacers safe and effective in inflammatory bowel disease patients?

Background: Prostate cancer radiotherapy (RT) in patients with (active) inflammatory bowel disease (IBD) remains controversial. We hypothesized that RT in combination with a biodegradable prostaterectum spacer balloon implantation, might be a safe treatment approach with acceptable toxicities for these high risk for rectal toxicity patients.Materials and methods: We report on a small prospective mono-centric series of 8 patients with all-risk prostate cancer with the comorbidity of an IBD. Four patients had Crohn's disease and 4 patients had ulcerative colitis. One out of four had an active status of IBD. All patients were intended to be treated with curative high-dose RT: 5 patients were treated with external beam RT (70 Gray (Gy) in 28 fractions), and 3 patients were treated with I-125-implant (145 Gy). Toxicities were scored according to the CTCAE v4.03: acute side effects occur up to 3 months after RT, and late side effects start after 3 months.Results: Median follow-up was 13 months (range: 3-42 months). Only one acute grade 2 gastrointestinal (GI) toxicity was observed: an increased diarrhea (4-6 above baseline) during RT, which resolved completely 6 weeks after treatment. No late grade 3 or more GI toxicity was reported, and no acute and late grade >= 2 genitourinary toxicity events were observed.Conclusion: Prostate cancer patients with IBD are a challenge to treat with RT. Our results suggest that RT in combination with a balloon implant in selective patients with (active) IBD may be promising, however additional validation is needed. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of European Society for Radiotherapy and Oncology.