Department of Radiation Oncology, London Health Sciences Centre, London, ON, Canada.
Department of Internal Medicine, University of Toronto, Toronto, ON, Canada.
Int J Radiat Oncol Biol Phys. 2020 Nov 1;108(3):575-586. doi: 10.1016/j.ijrobp.2020.06.008. Epub 2020 Jun 13.
Various radiation schedules are used in concurrent chemoradiation therapy for limited-stage small cell lung cancer (LS-SCLC). Since there is currently no randomized evidence comparing hypofractionated radiation therapy (HFRT) and conventionally fractionated radiation therapy (CFRT), the aim of this study was to compare overall survival (OS), progression-free survival (PFS), and toxicity of HFRT and CFRT in LS-SCLC.
Patients with LS-SCLC treated between 2000 and 2013 with HFRT (40 Gy/15 fractions, 45 Gy/15 fractions, 45 Gy/20 fractions) or CFRT (60 Gy/30 or 66 Gy/33 fractions) were included. Propensity scores were generated using a multivariable logistic regression model. Patients were matched on a 1:1 ratio with a caliper distance of 0.20. OS and PFS were estimated by the Kaplan-Meier method and compared using log-rank tests. As a sensitivity analysis, univariable and multivariable Cox regression was performed including all patients without matching. Logistic regression was performed to identify predictors of pulmonary and esophageal adverse events.
In the overall group of 117 patients, there were significant baseline differences between the HFRT and CFRT cohorts. Patients who received CFRT were older, more often smoked concurrently with treatment, had higher Eastern Cooperative Oncology Group performance status, different T and N stage patterns, and more commonly received concurrent chemoradiation therapy and prophylactic cranial irradiation. After propensity score matching for these differences, 72 patients were included, 36 in the HFRT and CFRT cohorts, respectively. There was no difference in OS (P = .724), PFS (P = .862), or any pulmonary (P = .350) or esophageal (P = .097) adverse events between cohorts. Skin adverse events were significantly higher for CFRT (41.7%) compared with HFRT (16.7%, P = .020). Multivariable Cox regression also revealed no differences in OS (P = .886) or PFS (P = .717) between all HFRT and CFRT patients, without matching. No grade 5 adverse events were observed.
In LS-SCLC patients, HFRT was associated with comparable survival and toxicity outcomes and may be considered as an alternative to CFRT, should its efficacy be confirmed in prospective studies.
局限期小细胞肺癌（LS-SCLC）同步放化疗中采用了多种放射治疗方案。由于目前尚无比较大分割放疗（HFRT）和常规分割放疗（CFRT）的随机证据，本研究旨在比较 LS-SCLC 中 HFRT 和 CFRT 的总生存（OS）、无进展生存（PFS）和毒性。
纳入 2000 年至 2013 年间接受 HFRT（40 Gy/15 次，45 Gy/15 次，45 Gy/20 次）或 CFRT（60 Gy/30 次或 66 Gy/33 次）治疗的 LS-SCLC 患者。采用多变量逻辑回归模型生成倾向评分。使用卡尺距离为 0.20 的 1:1 比例进行患者匹配。采用 Kaplan-Meier 法估计 OS 和 PFS，并通过对数秩检验进行比较。作为敏感性分析，对未匹配的所有患者进行单变量和多变量 Cox 回归。采用逻辑回归确定肺部和食管不良事件的预测因素。
在 117 例患者的总体人群中，HFRT 和 CFRT 队列之间存在显著的基线差异。接受 CFRT 的患者年龄较大，治疗期间更常同时吸烟，Eastern Cooperative Oncology Group 表现状态较高，T 和 N 期模式不同，更常接受同步放化疗和预防性颅脑照射。在对这些差异进行倾向评分匹配后，纳入 72 例患者，HFRT 和 CFRT 队列各 36 例。两组之间的 OS（P=0.724）、PFS（P=0.862）或任何肺部（P=0.350）或食管（P=0.097）不良事件均无差异。CFRT 组（41.7%）的皮肤不良事件明显高于 HFRT 组（16.7%，P=0.020）。多变量 Cox 回归也显示，未匹配时，所有 HFRT 和 CFRT 患者的 OS（P=0.886）或 PFS（P=0.717）均无差异。未观察到 5 级不良事件。
在 LS-SCLC 患者中，HFRT 与相似的生存和毒性结果相关，在前瞻性研究证实其疗效后，可考虑替代 CFRT。
