S1476
Interdisciplinary - Patient involvement
ESTRO 2026
for prostate radiotherapy simulation: feasibility and anatomical impact Gonzalo Ulloa 1 , Catalina Hérnandez 2 , Vanessa Ibáñez- Córdova 2 , Paula Reyes 1 , Eugenio Vinés 1 , Juan Pablo Canales 1 1 Department of Hematology – Oncology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile. 2 Cancer Center UC, Red de Salud Christus-UC, Santiago, Chile Purpose/Objective: To evaluate the feasibility, adherence, and anatomical impact of a standardized low-residue, low-gas diet implemented before simulation and during prostate radiotherapy (RT). The primary aim was to describe adherence and rectal anatomy at simulation; secondary aims included patient-reported tolerance
patient-centered strategy to optimize reproducibility in prostate RT, warranting validation in larger cohorts with daily image guidance data.
and digestive effects. Material/Methods:
A prospective institutional cohort of 11 consecutive patients receiving definitive, adjuvant, or salvage RT for prostate cancer was analyzed. All patients received written dietary instructions to reduce intestinal gas and stool retention during simulation and throughout treatment. The dietary guidelines were explained and delivered by a trained nursing team specialized in radiotherapy patient preparation. Collected variables included rectal diameter (cm) at the mid-prostate level on simulation CT, treatment characteristics, and three time-point measures of adherence (“Completely”, “Mostly”). Patient-reported outcomes included ease of following the diet (1–4 scale) and digestive changes. Descriptive statistics and stratification by mean adherence score (0–2) were performed. Results: Median age was 70 years [61–77]; RT indications were definitive (64%), salvage (27%), and oligometastatic (9%). Most patients received conventional/moderate hypofractionation (20×3 Gy, 64%); 4 (36%) underwent SBRT (5×7–7.25 Gy). ADT was used in 91%. Median rectal diameter was 2.7 cm (1.7–4.0), with similar values across adherence levels. The mean adherence score was 1.9 ± 0.3, showing high and consistent compliance: “Completely” at simulation 55%, during RT 73%, and at completion 73%. Median difficulty was 2 (“Little”). Patient-reported digestive effects were favorable: less gas in 55%, improved bowel transit in 36%, and no change in 9%. No interruptions or replanning were required, and all patients completed RT as planned. Conclusion: Implementation of a simple, standardized dietary protocol was highly feasible and well tolerated, with excellent adherence and consistent rectal anatomy during RT. Patients reported clear digestive benefits and minimal effort to follow the diet. These results support routine dietary preparation as a low-cost,
References: Schaefer C, Zamboglou C, Volegova-Neher N, et al. Impact of a low-FODMAP diet on rectal gas and volume during prostate radiotherapy: a pilot study. Radiat Oncol. 2020;15:27.Forslund M, Ottenblad A, Ginman C, et al. Nutrition intervention effects on bowel symptoms and QoL up to 24 months post-RT for
Made with FlippingBook - Share PDF online