倾向性评分匹配评价术后放疗在局限期小细胞肺癌的价值

Evaluation of postoperative radiotherapy in limited-stage small cell lung cancer with propensity score matching analysis

摘要:

目的：分析局限期小细胞肺癌根治术后辅助放疗（postoperative radiotherapy，PORT）的作用。方法：回顾性分析美国监测、流行病学和最终结果（surveillance，epidemiology，and end results，SEER）数据库中2000年至2016年915例接受手术治疗的局限期小细胞肺癌患者临床资料，通过对PORT（+）组及PORT（-）组资料应用倾向评分匹配法（propensity score matching，PSM）来均衡组间协变量差异，采用Kaplan-Meier法及log-rank检验进行生存分析，比较2组患者的总生存率（overall survival，OS）和肺癌特异性生存率（lung cancer specific survival，LCSS），分析术后放疗的作用及获益人群。结果：全组中位OS与LCSS分别为31个月和37个月；在进行倾向评分匹配前后，PORT（+）及PORT（-）组的OS及LCSS均无统计学差异。亚组分析显示所有N分期的OS和LCSS均无差异（N0：中位OS 61个月 vs. 62个月，P=0.838；N1：中位OS 22个月 vs. 20个月，P=0.735；N2：中位OS 19个月 vs. 16个月，P=0.254）。对淋巴结比率（lymph node ratio，LNR）亚组分析显示，当LNR大于50%时，PORT（+）组存在OS的获益（HR=0.57，95%CI=0.35~0.93；P=0.024），在LCSS上也存在明显获益（HR=0.57，95%CI 0.34~0.95；P=0.030）。多因素分析显示患者年龄、手术方式、LNR、T分期、N分期是局限期小细胞肺癌术后生存率独立的预后影响因素。结论：术后放疗与N0、N1和N2患者的生存率没有关系，与PORT相关的生存获益似乎仅限于LNR为50％或更高的患者。需在其他同类研究和随机对照试验中进一步评估。

Abstract:

Objective：To investigate the role of postoperative radiotherapy（PORT） in resected limited-stage small cell lung cancer（SCLC）. Methods：The clinical data of 915 patients with limited-stage SCLC from the SEER（surveillance，epidemiology，and end results） database who received surgical treatment in 2000-2016 were retrospectively analyzed. Propensity score matching（PSM） method was used to balance the covariate bias between PORT（+） and PORT（-） groups. The survival curves were drawn by Kaplan-Meier method，and log-rank test was used to check survival difference of two groups. Overall survival（OS） and lung cancer specific survival（LCSS） were compared between these two patient groups，and the role of postoperative radiotherapy and the subgroups that benefited from postoperative radiotherapy were analyzed. Results：The median OS and LCSS were 31 months and 37 months respectively. There was no significant difference in OS and LCSS between PORT（+） and PORT（-） groups before and after the propensity score matching. When analyzed by subgroup，no differences in OS and LCSS were observed in patients with all N stages（N0，median OS：61 months vs. 62 months；P=0.838；N1，median OS：22 months vs. 20 months；P=0.735；N2，median OS：19 months vs. 16 months；P=0.254）. Patients whose lymph node ratio（LNR） was greater than 50% had significantly improved OS（HR=0.57，95%CI=0.35-0.93；P=0.024） and LCSS（HR=0.57，95%CI=0.34-0.95；P=0.030）with PORT. Multivariate analysis showed that age，type of surgery，LNR，T stage and N stage were independent prognostic factors in patients with resected limited-stage SCLC. Conclusion：The use of PORT has no relationship with the survival of N0，N1 and N2 patients. The survival benefit associated with PORT in this disease seems to be limited to those with LNR of 50% or more. This needs to be further evaluated in other similar studies and randomized controlled trials.