Shenker Rachel, Eckrich Carolyn, D'Anna Rachel, Niedzwiecki Donna, Rodrigues Anna, Craciunescu Oana, Chino Junzo
Departments of Radiation Oncology.
Medical Physics.
Adv Radiat Oncol. 2023 Mar 1;8(4):101208. doi: 10.1016/j.adro.2023.101208. eCollection 2023 Jul-Aug.
In this prospective trial, we aim to determine whether fluorodeoxyglucose positron emission tomography and computed tomography (PET/CT)-based adaptive radiation therapy (ART) improves dosimetry outcomes for patients treated with definitive radiation for locally advanced vulvar cancer.
Patients were enrolled in 2 sequential institutional review board-approved prospective protocols for PET/CT ART from 2012 to 2020. Patients were planned with pretreatment PET/CT to 45 to 56 Gy in 1.8 Gy/fraction, followed by a boost to gross disease (nodal and/or primary) to a total of 64 to 66 Gy. Intratreatment PET/CT was obtained at 30 to 36 Gy, and all patients were replanned to the same dose goals with revised organ at risk (OAR), gross tumor volume, and planned target volume contours. Radiation therapy consisted of either intensity modulated radiation therapy or volumetric modulated arc therapy. Toxicity was graded by Common Terminology Criteria for Adverse Events, version 5.0. Local control, disease-free survival, overall survival, and time to toxicity were estimated using the Kaplan-Meier method. Dosimetry metrics for OARs were compared using the Wilcoxon signed rank test.
Twenty patients were eligible for analysis. Median follow-up among surviving patients was 5.5 years. Local control, disease-free survival, and overall survival at 2 years were 63%, 43%, and 68%, respectively. ART significantly reduced the following OAR doses: bladder, maximum dose (D; median reduction [MR], 1.1 Gy; interquartile range [IQR], 0.48-2.3 Gy; < .001) and D (MR, 1.5 Gy; IQR, 0.51-2.1 Gy; < .001); bowel, D (MR, 1.0 Gy; IQR, 0.11-2.9 Gy; < .001), D (MR, 0.39 Gy; IQR, 0.023-1.7 Gy; < .001), and D (MR, 0.19 Gy; IQR, 0.026-0.47 Gy; = .002); and rectal, mean dose (MR, 0.66 Gy; IQR, 0.17-1.7 Gy; = .006) and D (MR, 0.46 Gy; IQR, 0.17-0.80 Gy; = .006). No patients experienced any grade ≥3 acute toxicities. There were no reported late grade ≥2 vaginal toxicities. Lymphedema at 2 years was 17% (95% confidence interval, 0%-34%).
Doses to bladder, bowel, and rectum were significantly improved with ART, though the median magnitudes were modest. Which patients benefit most from adaptive treatment is a matter for future investigation.
在这项前瞻性试验中，我们旨在确定基于氟脱氧葡萄糖正电子发射断层扫描与计算机断层扫描（PET/CT）的自适应放射治疗（ART）是否能改善局部晚期外阴癌患者接受根治性放疗的剂量学结果。
2012年至2020年期间，患者入组了2个连续的经机构审查委员会批准的PET/CT ART前瞻性方案。患者在治疗前进行PET/CT计划，给予45至56 Gy，分1.8 Gy/次，随后对大体肿瘤（淋巴结和/或原发灶）进行加量，总量达64至66 Gy。在30至36 Gy时进行治疗中PET/CT，所有患者均根据修订的危及器官（OAR）、大体肿瘤体积和计划靶体积轮廓重新计划至相同的剂量目标。放射治疗包括调强放射治疗或容积调强弧形治疗。毒性按照《不良事件通用术语标准》第5.0版进行分级。使用Kaplan-Meier方法估计局部控制率、无病生存率、总生存率和出现毒性的时间。使用Wilcoxon符号秩检验比较OAR的剂量学指标。
20例患者符合分析条件。存活患者的中位随访时间为5.5年。2年时的局部控制率、无病生存率和总生存率分别为63%、43%和68%。ART显著降低了以下OAR的剂量：膀胱，最大剂量（D；中位降低量[MR]，1.1 Gy；四分位间距[IQR]，0.48 - 2.3 Gy；P <.001）和D（MR，1.5 Gy；IQR，0.51 - 2.1 Gy；P <.001）；肠道，D（MR，1.0 Gy；IQR，0.11 - 2.9 Gy；P <.001），D（MR，0.39 Gy；IQR，0.023 - 1.7 Gy；P <.001），和D（MR，0.19 Gy；IQR，0.026 - 0.47 Gy；P =.002）；直肠，平均剂量（MR，0.66 Gy；IQR，0.17 - 1.7 Gy；P =.006）和D（MR，0.46 Gy；IQR，0.17 - 0.80 Gy；P =.006）。没有患者出现任何≥3级急性毒性反应。没有报告≥2级晚期阴道毒性反应。2年时淋巴水肿发生率为17%（95%置信区间，0% - 34%）。
ART显著改善了膀胱、肠道和直肠的剂量，尽管中位改善幅度不大。哪些患者从自适应治疗中获益最大有待未来研究。
