立体定向放射治疗（SABR）用于治疗肺部肿瘤，但可能导致毒性效应，包括对中央结构的威胁生命的损害。回顾性数据表明，体积小于10 cm^3 的小肿瘤可以通过生物学有效剂量低于100 Gy 得到良好控制。为评估通过肿瘤大小、位置和组织学特征个体化调节肺部SABR剂量和分割次数是否与局部肿瘤控制有关。本非随机对照试验（iSABR试验，即个体化SABR）是一项二期多中心试验，于2011年11月15日至2018年12月5日在美国和日本的学术医疗中心招募参与者。数据分析时间为2020年12月9日至2023年5月10日。根据癌症类型，将病人分为三组：非小细胞肺癌（NSCLC）首次诊断，美国癌症联合委员会第七版T1-3N0M0肿瘤（组1），先前NSCLC或多个NSCLC的新T1-3N0M0原发性NSCLC（组2），或来自NSCLC或其他实体肿瘤的肺转移（组3）。最多可治疗四个肿瘤，采用每日一次的SABR。针对体积为0至10 cm^3 的外围肿瘤，剂量范围为25 Gy，而对于体积大于30 cm^3 的中央肿瘤，剂量为60 Gy，分为8次施放。每组在1年时的无局部复发率（同侧复发），在发生远处复发、死亡或随访结束时进行判别。共有217名不同的患者（年龄中位数[IQR]，72 [64-80]岁；男性129人[59%]；目前或曾经吸烟者150人[69%]）被纳入试验（有些患者重复纳入）。共进行240个疗程：组1的79个，组2的82个，组3的79个。共治疗285个肿瘤（211个[74%]外围肿瘤和74个[26%]中央肿瘤）。最常用的剂量是每次25 Gy（共158个肿瘤）。中位（范围）随访期为33个月（2-109个月），中位总生存期为59个月（95% CI，49-82个月）。组1的1年无局部复发率为97%（90% CI，91%-99%），组2为94%（90% CI，87%-97%），组3为96%（90% CI，89%-98%）。三个组的5年无局部复发率分别为83%至93%。患者出现3到5级毒性效应的比例很低，仅为5%（包括一个患者[1%]出现5级毒性效应）。这个非随机对照试验的结果表明，用于治疗肺部肿瘤的个体化SABR（iSABR）可实现治疗剂量的最小化，并与良好的局部控制相关。个体化剂量应在未来试验中予以考虑使用。ClinicalTrials.gov 识别号：NCT01463423。

Stereotactic ablative radiotherapy (SABR) is used for treating lung tumors but can cause toxic effects, including life-threatening damage to central structures. Retrospective data suggested that small tumors up to 10 cm3 in volume can be well controlled with a biologically effective dose less than 100 Gy.To assess whether individualizing lung SABR dose and fractionation by tumor size, location, and histological characteristics may be associated with local tumor control.This nonrandomized controlled trial (the iSABR trial, so named for individualized SABR) was a phase 2 multicenter trial enrolling participants from November 15, 2011, to December 5, 2018, at academic medical centers in the US and Japan. Data were analyzed from December 9, 2020, to May 10, 2023. Patients were enrolled in 3 groups according to cancer type: initial diagnosis of non-small cell lung cancer (NSCLC) with an American Joint Committee on Cancer 7th edition T1-3N0M0 tumor (group 1), a T1-3N0M0 new primary NSCLC with a history of prior NSCLC or multiple NSCLCs (group 2), or lung metastases from NSCLC or another solid tumor (group 3).Up to 4 tumors were treated with once-daily SABR. The dose ranged from 25 Gy in 1 fraction for peripheral tumors with a volume of 0 to 10 cm3 to 60 Gy in 8 fractions for central tumors with a volume greater than 30 cm3.Per-group freedom from local recurrence (same-lobe recurrence) at 1 year, with censoring at time of distant recurrence, death, or loss to follow-up.In total, 217 unique patients (median [IQR] age, 72 [64-80] years; 129 [59%] male; 150 [69%] current or former smokers) were enrolled (some multiple times). There were 240 treatment courses: 79 in group 1, 82 in group 2, and 79 in group 3. A total of 285 tumors (211 [74%] peripheral and 74 [26%] central) were treated. The most common dose was 25 Gy in 1 fraction (158 tumors). The median (range) follow-up period was 33 (2-109) months, and the median overall survival was 59 (95% CI, 49-82) months. Freedom from local recurrence at 1 year was 97% (90% CI, 91%-99%) for group 1, 94% (90% CI, 87%-97%) for group 2, and 96% (90% CI, 89%-98%) for group 3. Freedom from local recurrence at 5 years ranged from 83% to 93% in the 3 groups. The proportion of patients with grade 3 to 5 toxic effects was low, at 5% (including a single patient [1%] with grade 5 toxic effects).The results of this nonrandomized controlled trial suggest that individualized SABR (iSABR) used to treat lung tumors may allow minimization of treatment dose and is associated with excellent local control. Individualized dosing should be considered for use in future trials.ClinicalTrials.gov Identifier: NCT01463423.