Effect of Continuous Nutritionist-led Guidance on Bowel Preparation in Patients Undergoing Prostate Stereotactic Body Radiation Treatment with Endorectal Spacing: A Prospective Pilot Trial

Objective: To evaluate the effect of a daily nutritionist consultation on rectal volume, gas, and prostate displacement during Stereotactic Body Radiation Treatment (SBRT) with an endorectal spacer. Methods: Twenty-six consecutive patients receiving 5 fraction SBRT with endorectal spacing were prospectively enrolled for an intensive daily nutritionist intervention utilizing biofeedback based on image guidance from each fraction. A retrospective control cohort receiving a standard bowel preparation was compared. Rectal volume, rectal gas, and prostate displacement were assessed by analysis of cone beam computed tomography. Data was analyzed using the SPSS statistics software. Results: Intense dietary intervention with biofeedback led to a consistently lower rectal gas score over 5 fractions (P<0.001) and less variability in rectal volume during prostate SBRT indicating a nonsignificant trend for superior preparation in the intervention group compared with controls, particularly for the first 2 fractions. However, there was no significant impact on prostate displacement as measured by couch correction. Conclusions: Intense dietary consultations effectively reduce rectal gas and variation of rectal volume during prostate SBRT with endorectal spacing. However, there was no advantage in reducing prostate displacement. Thus, labor-intensive daily nutritionist intervention with biofeedback is not cost-effective in reducing organ motion in patients with endorectal spacers compared with standard pretreatment dietary advice and is not recommended.