Malygina Hanna, Auerbach Hendrik, Nuesken Frank, Palm Jan, Hecht Markus, Dzierma Yvonne
Department of Radiotherapy and Radiation Oncology, Saarland University Medical Centre, Kirrberger Str. 100, 66421, Homburg, Saar, Germany.
Strahlenther Onkol. 2025 Jan;201(1):47-56. doi: 10.1007/s00066-024-02306-7. Epub 2024 Oct 29.
Many patients find it challenging to comply with instructions regarding rectum and bladder filling during pelvic radiotherapy. With the implementation of online adaptive radiotherapy, the reproducibility of organ volumes is no longer a prerequisite. This study aims to analyze the sparing of the bladder and the posterior rectum wall (PRW) in conditions of full versus empty bladder and rectum.
280 fractions from 14 patients with prostate cancer who underwent adaptive radiotherapy using the Varian Ethos system were analyzed post-hoc. Various metrics for the bladder and PRW were correlated with respect to organ volume.
Our analysis quantitatively confirms the advantage of a full bladder during radiotherapy, as metrics V48Gy and V40Gy significantly inversely correlate with bladder filling for each patient individually. While bladder volume did not show a gradual decrease over the course of radiotherapy, it was observed to be higher during planning CT scans compared to treatment sessions. A full rectum condition either significantly improved (in 2 out of 7 patients) or at least did not impair (in 5 out of 7 patients) PRW sparing, as represented by the V30Gy metric, when patients were compared individually. The average V30Gy across all patients demonstrated a significant improvement in PRW sparing for the full rectum condition, with a [Formula: see text]-value of 0.039.
Despite the implementation of adaptive therapy, maintaining a high bladder filling remains important. However, the recommendation for rectum filling can be abandoned, as reproducibility is not critical for adaptive radiotherapy and no dosimetric advantage per se is associated with an empty rectum. Patients may even be encouraged not to void their bowels shortly before treatment, as long as this is tolerated over the treatment session.
许多患者发现在盆腔放疗期间遵守直肠和膀胱充盈的指示具有挑战性。随着在线自适应放疗的实施，器官体积的可重复性不再是一个先决条件。本研究旨在分析膀胱和直肠后壁（PRW）在膀胱和直肠充盈与排空状态下的受量情况。
对14例使用瓦里安Ethos系统进行自适应放疗的前列腺癌患者的280个分次进行事后分析。将膀胱和PRW的各种指标与器官体积进行相关性分析。
我们的分析定量证实了放疗期间膀胱充盈的优势，因为指标V48Gy和V40Gy与每位患者的膀胱充盈程度呈显著负相关。虽然膀胱体积在放疗过程中没有逐渐减小，但在计划CT扫描时观察到其比治疗期间更高。当对患者进行个体比较时，以V30Gy指标表示，直肠充盈状态要么显著改善（7例中的2例），要么至少不损害（7例中的5例）PRW的受量。所有患者的平均V30Gy显示直肠充盈状态下PRW的受量有显著改善，P值为0.039。
尽管实施了自适应治疗，但保持高膀胱充盈度仍然很重要。然而，直肠充盈的建议可以放弃，因为可重复性对于自适应放疗并不关键，并且直肠排空本身并没有剂量学优势。甚至可以鼓励患者在治疗前不久不解大便，只要在治疗期间能够耐受。
