Hui Caressa, Simiele Eric, Lozko Yuliia, Romero Ignacio, Skinner Lawrie, Binkley Michael Sargent, Hoppe Richard, Kovalchuk Nataliya, Hiniker Susan M
Department of Radiation Oncology, Stanford University, Stanford, CA, United States.
Department of Radiation Oncology, University of California Irvine, Irvine, CA, United States.
Front Oncol. 2024 Sep 16;14:1459287. doi: 10.3389/fonc.2024.1459287. eCollection 2024.
Volumetric modulated arc therapy (VMAT) total body irradiation (TBI) allows for greater organ sparing with improved target coverage compared to 2D-TBI. However, there is limited evidence of whether improved organ sparing translates to decreases in toxicities and how its toxicities compare to those of the 2D technique. We aimed to compare differences in toxicities among patients treated with TBI utilizing VMAT and 2D techniques.
METHODS/MATERIALS: A matched-pair single-institution retrospective analysis of 200 patients treated with TBI from 2014 to 2023 was performed. Overall survival (OS) and progression-free survival (PFS) were analyzed using the Kaplan-Meier method and compared using log-rank tests. Differences in characteristics and toxicities between the VMAT and 2D cohorts were compared using Fisher's exact test.
Of the 200 patients analyzed, 100 underwent VMAT-TBI, and 100 underwent 2D-TBI. The median age for VMAT-TBI and 2D-TBI patients was 13.7 years and 16.2 years, respectively ( = 0.25). In each cohort, 53 patients were treated with myeloablative regimens (8-13.76 Gy), and 47 were treated with non-myeloablative regimens (2-4 Gy). For the entire VMAT-TBI cohort, lung Dmean, kidney Dmean, and lens Dmax were spared to 60.6% ± 5.0%, 71.0% ± 8.5%, and 90.1% ± 3.5% of prescription, respectively. For the non-myeloablative VMAT-TBI cohort, testis/ovary Dmax, brain, and thyroid Dmean were spared to 33.4% ± 7.3%, 75.4% ± 7.0%, and 76.1% ± 10.5%, respectively. For 2D-TBI, lungs were spared using partial-transmission lung blocks for myeloablative regimens. The VMAT-TBI cohort experienced significantly lower rates of any grade of pneumonitis (2% vs. 12%), nephrotoxicity (7% vs. 34%), nausea (68% vs. 81%), skin (16% vs. 35%), and graft versus host disease (GVHD) (42% vs. 62%) compared to 2D-TBI patients. For myeloablative regimen patients, rates of pneumonitis (0% vs. 17%) and nephrotoxicity (9% vs. 36%) were significantly lower with VMAT-TBI versus 2D-TBI ( < 0.01). Median follow-up was 14.3 months, and neither median OS nor PFS for the entire cohort was reached. In the VMAT versus 2D-TBI cohort, the 1-year OS was 86.0% versus 83.0% ( = 0.26), and the 1-year PFS was 86.6% and 80.0% ( = 0.36), respectively.
Normal tissue sparing with VMAT-TBI compared to the 2D-TBI translated to significantly lower rates of pneumonitis, renal toxicity, nausea, skin toxicity, and GVHD in patients, while maintaining excellent disease control.
与二维全身照射（2D-TBI）相比，容积调强弧形放疗（VMAT）全身照射（TBI）能更好地保护器官，同时改善靶区覆盖。然而，关于更好的器官保护是否能转化为毒性降低以及其毒性与二维技术相比如何，证据有限。我们旨在比较采用VMAT和二维技术进行TBI治疗的患者之间的毒性差异。
方法/材料：对2014年至2023年在单一机构接受TBI治疗的200例患者进行配对回顾性分析。采用Kaplan-Meier方法分析总生存期（OS）和无进展生存期（PFS），并使用对数秩检验进行比较。使用Fisher精确检验比较VMAT组和二维组之间的特征和毒性差异。
在分析的200例患者中，100例接受了VMAT-TBI，100例接受了2D-TBI。VMAT-TBI组和2D-TBI组患者的中位年龄分别为13.7岁和16.2岁（P = 0.25）。在每个队列中，53例患者接受了清髓性方案（8 - 13.76 Gy）治疗，47例接受了非清髓性方案（2 - 4 Gy）治疗。对于整个VMAT-TBI队列，肺平均剂量（Dmean）、肾平均剂量和晶状体最大剂量（Dmax）分别被保护至处方剂量的60.6%±5.0%、71.0%±8.5%和90.1%±3.5%。对于非清髓性VMAT-TBI队列，睾丸/卵巢Dmax、脑和甲状腺Dmean分别被保护至33.4%±7.3%、75.4%±7.0%和76.1%±10.5%。对于2D-TBI，采用部分透射肺挡块对清髓性方案的患者进行肺部保护。与2D-TBI患者相比，VMAT-TBI队列中任何级别的肺炎（2%对12%）、肾毒性（7%对34%）、恶心（68%对81%）、皮肤毒性（16%对35%）和移植物抗宿主病（GVHD）（42%对62%）的发生率均显著降低。对于清髓性方案的患者，VMAT-TBI组的肺炎（0%对17%）和肾毒性（9%对36%）发生率显著低于2D-TBI组（P < 0.01）。中位随访时间为14.3个月，整个队列的中位OS和PFS均未达到。在VMAT组与2D-TBI组中，1年OS分别为86.0%和83.0%（P = 0.26），1年PFS分别为86.6%和80.0%（P = 0.36）。
与2D-TBI相比，VMAT-TBI对正常组织的保护使患者的肺炎、肾毒性、恶心、皮肤毒性和GVHD发生率显著降低，同时保持了良好的疾病控制。
