介绍手术是一个选择为患者大,有症状的原发性肿瘤影响大脑。然而,手术可能不适合所有肿瘤,特别是那些位于敏感区域,如松果体区和下丘脑。由于初始肿瘤体积和风险辐射敏感器官(OAR)的参与,单次立体定向放射外科(SRS)可能无法为长期局部控制提供足够的剂量。两节放射外科已被描述为大型继发性脑肿瘤剂量递增的可行策略。该报告描述了一系列因影响大脑的原发性肿瘤而接受两次放射外科治疗的患者。材料和方法从2017年5月至2020年1月,由于最初的大肿瘤体积或肿瘤定位以及OAR的参与,对八名影响大脑的原发性肿瘤患者进行了两次放射外科治疗。通过影像学和临床评估评估反应。结果共治疗8例,九种肿瘤接受了两次放射治疗,四名患者在松果体区域有肿瘤(50%),其余的在下丘脑区(25%)或其他地方。第一次SRS疗程的平均肿瘤体积为15mL(范围为5.2至51.6mL),平均处方剂量为13Gy,两次会议之间的时间间隔为30天(范围,30至42天)。在第二届会议期间,肿瘤体积减少到73.6%(范围,-20%到98.7%)的原始尺寸,平均肿瘤体积为5mL(范围,0.1至17.8毫升),第二次会议的平均处方剂量为16.2Gy,按时间估计,剂量,和分级和生物等效剂量下的α-β值通常相当于15.8Gy的单剂量。光学通路的OAR剂量相当于9.75Gy的单次最大剂量(范围,7.12to10.92),和脑干,当量为最大剂量12.3Gy(范围,5.6至15.07)。在最后的随访中,平均为336.5天(范围,65至962天),七个病人还活着,五个肿瘤有部分反应(PR),根据实体瘤反应评估标准(RECIST)标准,3人病情稳定。一名患者在治疗后435天死亡,Karnofsky绩效状态(KPS)在第一届会议上是90,90在第二届会议上,并在最后一次随访中保持不变。没有不良辐射影响的报告。结论两阶段SRS被证明是一种安全的方法,可以在大体积的原发性脑肿瘤中增加剂量,这些肿瘤的组织学有望对辐射产生快速的生物学反应。需要更长的随访以确定两阶段SRS的肿瘤亚型的长期有效性,其方式与在较小肿瘤体积的单次SRS系列中已证明的方式相同。
Introduction Surgery is an option for patients with large, symptomatic primary tumors affecting the brain. However, surgery might not be suitable for all tumors, especially those located in sensitive areas such as the pineal region and the hypothalamus. Single-session stereotactic radiosurgery (SRS) might not provide an adequate dose for long-term local control due to the initial tumor volume and the involvement of radiation sensitive organs at risk (OARs). Two-session radiosurgery has been described as a feasible strategy for dose escalation in large secondary brain tumors. This report describes a series of patients treated upfront with two-session radiosurgery for primary tumors affecting the brain. Materials and methods From May 2017 to January 2020, eight patients with primary tumors affecting the brain were treated with two-session radiosurgery due to either an initial large tumor volume or tumor localization and the involvement of OARs. The response was assessed by imaging and clinical evaluations. Results A total of eight patients were treated, nine tumors were treated with two-session radiosurgery, four patients had tumors in the pineal region (50%), and the rest were in the hypothalamic region (25%) or elsewhere. The mean tumor volume for the first SRS session was 15 mL (range 5.2 to 51.6 mL), the mean prescription dose was 13 Gy, and the timespan between both sessions was 30 days (range, 30 to 42 days). During the second session, tumor volume was reduced to 73.6% (range, -20% to 98.7%) of the original dimension, mean tumor volume was 5 mL (range, 0.1 to 17.8 ml), mean prescription dose for the second session was 16.2 Gy estimated by time, dose, and fractionation and by bioequivalent dose under alpha-beta values often to be equivalent to a single dose of 15.8 Gy. Doses to the OARs for the optic pathway were equivalent to a single maximum dose of 9.75 Gy (range, 7.12 to 10.92), and to the brainstem, the equivalent was a maximum dose of 12.3 Gy (range, 5.6 to 15.07). At last follow-up, at a mean of 336.5 days (range, 65 to 962 days), seven patients were alive, five tumors had a partial response (PR), and three had stable disease in accordance to Response Evaluation Criteria in Solid Tumors (RECIST) criteria. One patient died 435 days after treatment, the Karnofsky Performance Status (KPS) was 90 at the first session, 90 at the second session, and was maintained at last follow-up. No adverse radiation effects were reported. Conclusions Two-stage SRS proved to be a safe method to escalate dose in proportionately large volume primary brain tumors whose histology is expected to have a quick biological response to radiation. Longer follow-up is needed to determine the long-term effectiveness by tumor subtypes of two-stage SRS in the same manner as it has been proven in single session SRS series in smaller tumor volumes.