Impact of a low FODMAP diet on the amount of rectal gas and rectal volume during radiotherapy in patients with prostate cancer - a prospective pilot study

Radiat Oncol. 2020 Jan 30;15(1):27. doi: 10.1186/s13014-020-1474-y.

Abstract

Background: Small inter- and intrafractional prostate motion was shown to be a prerequisite for precise radiotherapy (RT) of prostate cancer (PCa) to achieve good local control and low rectal toxicity. As rectal gas and rectal volume are known to have a relevant effect on prostate motion, this study aims to reduce these parameters by using a Low FODMAP Diet (LFD) and to show feasibility of this intervention.

Methods: We compared a prospective intervention group (IG, n = 25) which underwent RT for PCa and whose patients were asked to follow a LFD during RT with a retrospective control group (CG, n = 25) which did not get any dietary advice. In the planning CT scan and all available cone beam CT scans rectal gas was classified based on a semiquantitative score (scale from 1 to 5) and rectal volume was measured. Furthermore, patients' compliance was evaluated by a self-assessment questionnaire.

Results: Clinical and treatment characteristics were well balanced between both groups. A total of 266 (CG, 10.6 per patient) and 280 CT scans (IG, 11.2 per patient), respectively, were analysed. The frequency distribution of gas scores differed significantly from each other (p < .001) with the IG having lower scores. Rectal volume was smaller in the IG (64.28 cm3, 95% CI 60.92-67.65 cm3, SD 28.64 cm3) than in the CG (71.40 cm3, 95% CI 66.47-76.32 cm3, SD 40.80 cm3) (p = .02). Mean intrapatient standard deviation as a measure for the variability of rectal volume was 22 cm3 in the IG and 23 cm3 in the CG (p = .81). Patients' compliance and contentment were satisfying.

Conclusions: The use of a LFD significantly decreased rectal gas and rectal volume. LFD was feasible with an excellent patients' compliance. However, prospective trials with a larger number of patients and a standardized evaluation of gastrointestinal toxicity and quality of life are reasonable.

Trial registration: German Clinical Trials Register, DRKS00012955. Registered 29 August 2017 - Retrospectively registered, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00012955.

Keywords: Low FODMAP diet; Radiotherapy - prostate Cancer; Rectal gas; Rectal volume.

Publication types

  • Clinical Trial

MeSH terms

  • Aged
  • Diet, Carbohydrate-Restricted*
  • Germany
  • Humans
  • Male
  • Middle Aged
  • Motion
  • Patient Compliance
  • Pilot Projects
  • Prospective Studies
  • Prostate / radiation effects
  • Prostatic Neoplasms / diet therapy*
  • Prostatic Neoplasms / pathology
  • Prostatic Neoplasms / radiotherapy
  • Radiotherapy, Intensity-Modulated / adverse effects
  • Rectum / diagnostic imaging
  • Rectum / pathology*
  • Rectum / physiopathology*
  • Rectum / radiation effects
  • Treatment Outcome