Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, The Netherlands; Research Group Healthy Ageing, Allied Health Care and Nursing, Hanze University of Applied Sciences, Groningen, The Netherlands.
Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, The Netherlands.
Radiother Oncol. 2016 Jun;119(3):381-7. doi: 10.1016/j.radonc.2016.04.005. Epub 2016 May 3.
Curative radiotherapy for prostate cancer may lead to anorectal side effects, including rectal bleeding, fecal incontinence, increased stool frequency and rectal pain. The main objective of this study was to develop multivariable NTCP models for these side effects.
The study sample was composed of 262 patients with localized or locally advanced prostate cancer (stage T1-3). Anorectal toxicity was prospectively assessed using a standardized follow-up program. Different anatomical subregions within and around the anorectum were delineated. A LASSO logistic regression analysis was used to analyze dose volume effects on toxicity.
In the univariable analysis, rectal bleeding, increase in stool frequency and fecal incontinence were significantly associated with a large number of dosimetric parameters. The collinearity between these predictors was high (VIF>5). In the multivariable model, rectal bleeding was associated with the anorectum (V70) and anticoagulant use, fecal incontinence was associated with the external sphincter (V15) and the iliococcygeal muscle (V55). Finally, increase in stool frequency was associated with the iliococcygeal muscle (V45) and the levator ani (V40). No significant associations were found for rectal pain.
Different anorectal side effects are associated with different anatomical substructures within and around the anorectum. The dosimetric variables associated with these side effects can be used to optimize radiotherapy treatment planning aiming at prevention of specific side effects and to estimate the benefit of new radiation technologies.
前列腺癌的根治性放疗可能导致直肠肛门副作用，包括直肠出血、大便失禁、排便频率增加和直肠疼痛。本研究的主要目的是建立这些副作用的多变量 NTCP 模型。
研究样本由 262 例局限性或局部进展性前列腺癌（T1-3 期）患者组成。采用标准化随访程序前瞻性评估直肠肛门毒性。在直肠肛门内及其周围勾画不同的解剖亚区。采用 LASSO 逻辑回归分析来分析剂量体积对毒性的影响。
在单变量分析中，直肠出血、排便频率增加和大便失禁与大量剂量学参数显著相关。这些预测因子之间的相关性很高（VIF>5）。在多变量模型中，直肠出血与直肠肛门（V70）和抗凝药物使用相关，大便失禁与外括约肌（V15）和髂尾肌（V55）相关，排便频率增加与髂尾肌（V45）和肛提肌（V40）相关。直肠疼痛与任何剂量学参数均无显著相关性。
不同的直肠肛门副作用与直肠肛门内及其周围的不同解剖亚结构相关。与这些副作用相关的剂量学变量可用于优化放疗计划，以预防特定的副作用，并估计新放疗技术的获益。
