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Abstract Introduction According to current International Association for the Study of Lung Cancer guideline, physicians may first use plasma cell‐free DNA (cfDNA) methods to identify epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI)‐resistant mechanisms (liquid rebiopsy) for lung cancer. Tissue rebiopsy is recommended if the plasma result is negative. However, this approach has not been evaluated prospectively using next‐generation sequencing (NGS). Methods We prospectively enrolled patients with lung cancer with first‐line EGFR‐TKI resistance who underwent tissue rebiopsy. The rebiopsied tissues and cfDNA were sequenced using targeted NGS, ACTDrug®+, and ACTMonitor®Lung simultaneously. The clinicopathological characteristics and treatment outcomes were analyzed. Results Totally, 86 patients were enrolled. Twenty‐six (30%) underwent tissue biopsy but the specimens were inadequate for NGS. Among the 60 patients with paired tissue and liquid rebiopsies, two‐thirds (40/60) may still be targetable. T790M mutations were found in 29, including 14 (48%) only from tissue and 5 (17%) only from cfDNA. Twenty‐four of them were treated with osimertinib, and progression‐free survival was longer in patients without detectable T790M in cfDNA than in patients with detectable T790M in cfDNA (p = 0.02). For the 31 T790M‐negative patients, there were six with mesenchymal–epithelial transition factor (MET) amplifications, four with ERBB2 amplifications, and one with CCDC6‐RET fusion. One with MET amplification and one with ERBB2 amplification responded to subsequent MET and ERBB2 targeting agents respectively. Conclusions NGS after EGFR‐TKI resistance may detect targetable drivers besides T790M. To do either liquid or tissue NGS only could miss patients with T790M. To do tissue and liquid NGS in parallel after EGFR‐TKI resistance may find more patients with targetable cancers.

Abstract Background Front‐line platinum‐base chemotherapy for advanced thymoma and thymic carcinoma (TC) improves resectability and prolongs patients' overall survival (OS). In this study, we evaluated patients' outcomes given different front‐line regimens: cisplatin, doxorubicin, and cyclophosphamide (CAP); cisplatin and etoposide (EP); or cisplatin and paclitaxel (TP). Materials and Methods We retrospectively evaluated the medical records of patients with advanced thymoma and TC who were treated at our medical center between 2005 and 2015. We investigated objective response rates (ORRs), progression‐free survival (PFS), and OS after undergoing different front‐line regimens. Results Among the 108 enrolled patients, 37 (34%) had thymoma and 71 (66%) had TC; 45 received CAP, 36 received EP, and 27 received TP regimens. The ORRs of patients receiving CAP, EP, and TP were 51%, 50%, and 41%, respectively. For patients with stage III and IVA disease, the median PFS after CAP, EP, and TP were 34.5, 26.4, and 18.0 months (p = 0.424), respectively, and the 5‐year OS rates were 84.9%, 70.6%, and 60.0% (p = 0.509). In patients with stage IVB disease, the median PFS were 9.4, 8.2, and 11.6 months after undergoing CAP, EP, and TP (p = 0.173), respectively, and the 5‐year OS rates were 41.1%, 39.1%, and 14.3% (p = 0.788). TC pathology subtype and liver metastasis were associated with poor OS. Three patients with stage IVB TC had an OS of more than 5 years. Conclusion Different front‐line chemotherapy regimens may provide similar long‐term PFS and OS in patients with advanced thymoma and TC. In addition to TC and liver metastasis were associated with poor OS, other potential prognostic factors are warranted for studying.