ORIGINAL RESEARCH article
Front. Oncol.
Sec. Radiation Oncology
Volume 15 - 2025 | doi: 10.3389/fonc.2025.1662671
This article is part of the Research TopicNext-Generation Radiotherapy for Prostate Cancer: Precision, Personalization, and Technological AdvancesView all 4 articles
Daily online adaptation enhances target coverage in prostate cancer radiotherapy: A retrospective analysis
Provisionally accepted
Hanna Malygina1*
Bryan Salazar Zuniga1Hendrik Auerbach1Marc Ries1Yvonne Dzierma1,2Markus Hecht1Jan Palm1- 1Saarland University Medical Center, Homburg, Germany
- 2Rostock University Medical Center, Rostock, Germany
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Introduction: Online adaptive radiotherapy aims to improve treatment quality by accounting for inter-fractional variation in anatomy. This study presents a quantitative comparison between adapted and non-adapted scheduled plans with identical margins in a real-world clinical setting. Methods: We retrospectively analyzed 422 fractions from 43 patients with prostate cancer treated with the Varian Ethos system. All patients received hypofractionated treatment with 3~Gy per fraction up to a cumulative dose of 60~Gy. For each fraction, the scheduled plan (planned on planning CT, calculated on synthetic CT derived from daily cone beam CT) was compared to the adapted plan (planned and calculated on actual daily anatomy) by means of several dose-volume metrics. Comparative statistics regarding dose-volume metrics were performed using Wilcoxon signed-rank test for paired data with a two-sided hypothesis. Results: Adapted plans delivered significantly better target coverage, conformality, and homogeneity than scheduled plans. The constraints D95%⩾95% and V95%⩾95% were met in 418 out of 422 fractions with the adapted plan, compared to only 41%-84% of fractions with the scheduled plan. Median absolute improvements for these metrics ranged between 1.5 and 6.0 percentage points. Most organ-at-risk metrics remained unchanged or showed only minor differences. Interquartile ranges decreased across all metrics. Conclusions: Adaptation significantly improved target dose metrics compared to non-adapted plans, without compromising organs-at-risk sparing. Interquartile ranges were reduced for all metrics evidencing better repeatability of adapted plans.
Keywords: prostate cancer, Online adaptive radiotherapy (oART), Varian Ethos, Dosimetric impact, Dosimetric distribution, organs-at-risksparing, CBCT
Received: 09 Jul 2025; Accepted: 16 Oct 2025.
Copyright: © 2025 Malygina, Salazar Zuniga, Auerbach, Ries, Dzierma, Hecht and Palm. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Hanna Malygina, hanna.malygina@uks.eu
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