Introduction: Histologic transformation from NSCLC to SCLC is a mechanism of resistance in EGFR‐mutant tumors but is also occasionally observed in nonmutated NSCLC. Methods: We performed a multicenter retrospective collection of cases presenting between 2005 and 2017. The objectives were to analyze survival data and to define epidemiologic, clinical, treatment and histomolecular characteristics at both the time of diagnosis of NSCLC and of SCLC. Results: Forty‐eight EGFR‐mutant NSCLC and 13 non–EGFR‐mutant cases were registered. Most EGFR‐mutant tumors retained the same EGFR mutation after transformation. The median time to SCLC transformation was shorter in the EGFR‐mutant group than in non‐EFGR mutants (16 months versus 26 months (p = 0.01)). Both tumors were responsive to platinum etoposide regimens (45% partial response for the EGFR‐mutant group versus 40% for non‐EFGR mutants). The median overall survival rates were 28 months in the EGFR‐mutant group versus 37 months in the non–EFGR‐mutant group, respectively. After transformation, the median overall survival was 9 months in the non–EGFR‐mutant group versus 10 months in the EGFR‐mutant group. Conclusions: Transformation into SCLC seems to occur more quickly in EGFR mutated tumors; however, once the tumor is transformed its survival and response to treatment seems comparable to that of classical SCLC.

中文翻译：

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非小细胞肺癌向小细胞肺癌转化的简要报告：分子和治疗特征

简介：从 NSCLC 到 SCLC 的组织学转化是 EGFR 突变肿瘤的一种耐药机制，但也偶尔在非突变 NSCLC 中观察到。方法：我们对 2005 年至 2017 年间出现的病例进行了多中心回顾性收集。目的是分析生存数据，并确定 NSCLC 和 SCLC 诊断时的流行病学、临床、治疗和组织分子特征。结果：登记了 48 例 EGFR 突变 NSCLC 和 13 例非 EGFR 突变病例。大多数 EGFR 突变肿瘤在转化后保留了相同的 EGFR 突变。EGFR 突变组的 SCLC 转化中位时间比非 EFGR 突变组短（16 个月对 26 个月（p = 0.01））。两种肿瘤都对铂类依托泊苷方案有反应（EGFR 突变组的部分反应为 45%，而非 EFGR 突变组的部分反应为 40%）。EGFR 突变组的中位总生存率分别为 28 个月和非 EFGR 突变组的 37 个月。转化后，非 EGFR 突变组的中位总生存期为 9 个月，而 EGFR 突变组为 10 个月。结论：在 EGFR 突变的肿瘤中，向 SCLC 的转化似乎发生得更快；然而，一旦肿瘤发生转化，其存活率和对治疗的反应似乎与经典 SCLC 相当。非EGFR突变组的中位总生存期为9个月，而EGFR突变组为10个月。结论：在 EGFR 突变的肿瘤中，向 SCLC 的转化似乎发生得更快；然而，一旦肿瘤发生转化，其存活率和对治疗的反应似乎与经典 SCLC 相当。非EGFR突变组的中位总生存期为9个月，而EGFR突变组为10个月。结论：在 EGFR 突变的肿瘤中，向 SCLC 的转化似乎发生得更快；然而，一旦肿瘤发生转化，其存活率和对治疗的反应似乎与经典 SCLC 相当。