Ong Ashley L K, Knight Kellie, Panettieri Vanessa, Dimmock Mathew, Tuan Jeffrey K L, Tan Hong Qi, Wright Caroline
National Cancer Centre Singapore, Division of Radiation Oncology, Singapore.
Monash University, Department of Medical Imaging and Radiation Sciences, Clayton, Australia.
Phys Imaging Radiat Oncol. 2022 Jul 16;23:97-102. doi: 10.1016/j.phro.2022.07.001. eCollection 2022 Jul.
Significant dose deviations have been reported between planned (D) and accumulated (D) dose in prostate radiotherapy. This study aimed to develop multivariate analysis (MVA) models associating Grade 1 and 2 gastrointestinal (GI) toxicity with clinical and D or D dosimetric variables separately.
Dose volume (DV) metrics were compared between D and D for 150 high-risk prostate cancer patients. MV models were generated from significant clinical and dosimetric variables (p < 0.05) at univariate level. Dose-based-region of interest (DB-ROI) metrics were included. Model performance was measured, and additional subgroup analysis were performed.
Rectal D demonstrated a higher intermediate-high dose (V and DB-ROI at 15-50 mm) compared to D. Conversely, at the very high dose region, rectal D (V and DB-ROI at 5-10 mm) were significantly lower. In MVA, rectal DB-ROI at 10 mm was predictive for Grade ≥ 1 GI toxicity for D and D. Age, rectal D for D, and rectal D for DB-ROI 10 mm were predictors for Grade 2 GI toxicity. Subgroup analysis revealed that patients ≥ 72 years old and a rectal D of ≥ 78.2 Gy were highly predictive of Grade 2 GI toxicity.
The dosimetric impact of a higher dose rectal dose in D due to volumetric changes was minimal and was not predictive of detrimental clinical toxicity apart from rectal D ≥ 78.2 Gy for Grade 2 GI toxicity. The use of the DB-ROI method can provide equivalent predictive power as the DV method in toxicity prediction.
据报道，前列腺放疗的计划剂量（D）与累积剂量（D）之间存在显著的剂量偏差。本研究旨在分别建立将1级和2级胃肠道（GI）毒性与临床及D或D剂量学变量相关联的多变量分析（MVA）模型。
比较了150例高危前列腺癌患者D和D的剂量体积（DV）指标。单变量水平上从显著的临床和剂量学变量（p < 0.05）生成MV模型。纳入了基于剂量的感兴趣区域（DB-ROI）指标。测量了模型性能，并进行了额外的亚组分析。
与D相比，直肠D在中高剂量（15 - 50 mm处的V和DB-ROI）显示更高。相反，在极高剂量区域，直肠D（5 - 10 mm处的V和DB-ROI）显著更低。在MVA中，10 mm处的直肠DB-ROI可预测D和D时≥1级GI毒性。年龄、D时的直肠D以及10 mm处DB-ROI的直肠D是2级GI毒性的预测因素。亚组分析显示，年龄≥72岁且直肠D≥78.2 Gy的患者高度预测2级GI毒性。
由于体积变化导致的D中较高剂量直肠剂量的剂量学影响最小，除了直肠D≥78.2 Gy导致2级GI毒性外，不能预测有害的临床毒性。在毒性预测方面，使用DB-ROI方法可提供与DV方法相当的预测能力。
