Zhang-Velten Elizabeth Ren, Parsons David, Lee Pam, Chambers Eric, Abdulrahman Ramzi, Desai Neil B, Dan Tu, Wardak Zabi, Timmerman Robert, Vusirikala Madhuri, Patel Prapti, Simms-Waldrip Tiffany, Aquino Victor, Koh Andrew, Tan Jun, Iqbal Zohaib, Zhang You, Reynolds Robert, Chiu Tsuicheng, Joo Mindy, Hrycushko Brian, Ouyang Luo, Lamphier Richard, Yan Yulong, Jiang Steve B, Kumar Kiran A, Gu Xuejun
Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas.
Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Radiation Oncology, Texas Tech University Health Science Center, Lubbock, Texas.
Transplant Cell Ther. 2022 Feb;28(2):113.e1-113.e8. doi: 10.1016/j.jtct.2021.10.020. Epub 2021 Nov 11.
Total body irradiation is an important part of the conditioning regimens frequently used to prepare patients for allogeneic hematopoietic stem cell transplantation (SCT). Volumetric-modulated arc therapy enabled total body irradiation (VMAT-TBI), an alternative to conventional TBI (cTBI), is a novel radiotherapy treatment technique that has been implemented and investigated in our institution. The purpose of this study is to (1) report our six-year clinical experience in terms of treatment planning strategy and delivery time and (2) evaluate the clinical outcomes and toxicities in our cohort of patients treated with VMAT-TBI. This is a retrospective single center study. Forty-four patients at our institution received VMAT-TBI and chemotherapy conditioning followed by allogeneic SCT between 2014 and 2020. Thirty-two patients (73%) received standard-dose TBI (12-13.2 Gy in 6-8 fractions twice daily), whereas 12 (27%) received low-dose TBI (2-4 Gy in one fraction). Treatment planning, delivery, and treatment outcome data including overall survival (OS), relapse-free survival (RFS), and toxicities were analyzed. The developed VMAT-TBI planning strategy consistently generated plans satisfying our dose constraints, with planning target volume coverage >90%, mean lung dose ∼50% to 75% of prescription dose, and minimal hotspots in critical organs. Most of the treatment deliveries were <100 minutes (range 33-147, mean 72). The median follow-up was 26 months. At the last follow-up, 34 of 44 (77%) of patients were alive, with 1- and 2-year OS of 90% and 79% and RFS of 88% and 71%, respectively. The most common grade 3+ toxicities observed were mucositis (31 patients [71%]) and nephrotoxicity (6 patients [13%]), both of which were deemed multifactorial in cause. Four patients (9%) in standard-dose cohort developed grade 3+ pneumonitis, with 3 cases in the setting of documented respiratory infection and only 1 (2%) deemed likely related to radiation alone. VMAT-TBI provides a safe alternative to cTBI. The dose modulation capability of VMAT-TBI may lead to new treatment strategies, such as simultaneous boost and further critical organ sparing, for better malignant cell eradication, immune suppression, and lower toxicities.
全身照射是常用于为异基因造血干细胞移植（SCT）患者进行预处理的预处理方案的重要组成部分。容积调强弧形放疗实现的全身照射（VMAT-TBI）是传统全身照射（cTBI）的替代方法，是一种已在我们机构实施并进行研究的新型放射治疗技术。本研究的目的是：（1）报告我们在治疗计划策略和照射时间方面的六年临床经验；（2）评估我们接受VMAT-TBI治疗的患者队列的临床结局和毒性。这是一项回顾性单中心研究。2014年至2020年期间，我们机构的44例患者接受了VMAT-TBI和化疗预处理，随后进行了异基因SCT。32例患者（73%）接受了标准剂量的全身照射（12 - 13.2 Gy，分6 - 8次，每天两次），而12例（27%）接受了低剂量全身照射（2 - 4 Gy，单次）。分析了治疗计划、照射及治疗结局数据，包括总生存期（OS）、无复发生存期（RFS）和毒性。所制定的VMAT-TBI计划策略始终能生成满足我们剂量限制的计划，计划靶区覆盖率>90%，平均肺剂量约为处方剂量的50%至'75%，关键器官中的热点最少。大多数治疗照射时间<100分钟（范围33 - 147分钟，平均72分钟）。中位随访时间为26个月。在最后一次随访时，44例患者中的34例（77%）存活，1年和2年总生存率分别为90%和79%，无复发生存率分别为88%和71%。观察到的最常见3级及以上毒性为粘膜炎（31例患者[71%]）和肾毒性（6例患者[13%]），两者病因均被认为是多因素的。标准剂量队列中的4例患者（9%）发生了3级及以上肺炎，其中3例在有记录的呼吸道感染情况下发生，仅1例（2%）被认为可能仅与放疗有关。VMAT-TBI为cTBI提供了一种安全的替代方法。VMAT-TBI的剂量调制能力可能会带来新的治疗策略，如同步推量和进一步保护关键器官，以更好地根除恶性细胞、实现免疫抑制并降低毒性。
