Purpose/Objectives: Adoption of hypofractionated accelerated radiation therapy (HART) with concurrent chemotherapy has been limited by toxicity concerns. We aimed to describe outcomes of patients treated with HART and concurrent chemotherapy and to evaluate dosimetry to organs at risk to guide patient selection.

Materials/Methods: We evaluated a retrospective cohort of NSCLC patients treated with concurrent chemotherapy with HART (>2.2 Gy per fraction) or standard fractionated radiation therapy (SFRT; 2-2.2 Gy fractions). Dosimetric parameters to key organs at risk were compared, and toxicity, patterns of recurrence and survival were calculated for the cohorts.

Results: Fifty-three patients treated with HART were compared with 100 patients treated with SFRT. Median dose per fraction for the HART cohort was 2.75 Gy (range 2.4–3 Gy). HART patients had significantly lower doses to the lung, heart, and esophagus due to patient selection. The HART group and had rates of grade 2+ pneumonitis (9.4 vs. 19%, p = 0.16) and grade 2+ esophagitis (20.8 vs. 45%, p < 0.01) that compared favorably to SFRT. Cumulative incidence of in-field recurrence trended lower in the HART cohort (7.6% versus 23.1%, p = 0.058). Among the HART group, 88.7% (47/53) met the newly proposed lung constraints based on the degree of hypofractionation

Conclusion: In select patients with favorable dosimetry to organs at risk, definitive HART with concurrent chemotherapy achieved excellent local control with low toxicity. These results are being used to inform a prospective study on the safety and efficacy of HART with concurrent chemotherapy for select NSCLC patients.

目的/目标：大分割加速放射治疗 (HART) 与同步化疗的采用因毒性问题而受到限制。我们的目的是描述接受 HART 和同步化疗的患者的结果，并评估有风险的器官的剂量测定，以指导患者选择。

材料/方法：我们评估了一组接受 HART 同步化疗（>2.2 Gy/分次）或标准分割放射治疗（SFRT；2-2.2 Gy 分次）的 NSCLC 患者回顾性队列。比较了关键危险器官的剂量学参数，并计算了各组的毒性、复发模式和生存率。

结果：将 53 名接受 HART 治疗的患者与 100 名接受 SFRT 治疗的患者进行了比较。HART 队列中每次分次的中位剂量为 2.75 Gy（范围 2.4-3 Gy）。由于患者的选择，HART 患者的肺、心脏和食道受到的剂量明显较低。HART 组的 2+ 级肺炎发生率（9.4 vs. 19%，p = 0.16）和 2+ 级食管炎发生率（20.8 vs. 45%，p < 0.01）优于 SFRT。HART 队列中现场复发的累积发生率呈较低趋势（7.6% 对比 23.1%，p  = 0.058）。在 HART 组中，88.7% (47/53) 符合新提出的基于大分割程度的肺部限制

结论：在对危险器官剂量测定有利的特定患者中，确定性 HART 联合化疗可实现良好的局部控制且毒性较低。这些结果被用来为一项关于 HART 与同步化疗对选定的 NSCLC 患者的安全性和有效性的前瞻性研究提供信息。