Suitability of Surgical Tumor Tissues, Biopsy, or Cytology Samples for Epidermal Growth Factor Receptor Mutation Testing in Non–Small Cell Lung Carcinoma Based on Chinese Population12

BACKGROUND Epidermal growth factor receptor (EGFR) mutation status is crucial in treatment selection for non-small cell lung cancer (NSCLC) patients; however, the detection materials' availability remains challenging in clinical practice. In this study, we collected surgical resection tissues, lymph node biopsy, and cytological samples for EGFR mutation testing and investigated the associations between gene mutation and clinical characteristics. METHODS Two hundred and seventy-six NSCLC adenocarcinoma specimens were collected, and highly sensitive amplification refractory mutation system method was implemented for EGFR mutation detection, with clinicopathologic characteristics involved in the final analysis. RESULTS In the total of 276 samples, 96% (265/276) of tumors obtained evaluable EGFR mutation status, the frequency of mutation was 55.8% (148/265) in all specimens, and three different type samples shared a comparable successful testing rate: 97.4% (38/39) in surgical tumor tissues, 100% (108/108) in lymph node biopsy samples, and 92.2% (119/129) in cytological samples. EGFR mutation was significantly associated with sex, smoking history, lymph node metastasis status (N stage), primary tumor size, testing tissues origin, and sample type (P < .05). Multivariate analysis reconfirmed that smoking history and primary tumor size shared significant correlation with EGFR mutation after adjustment. CONCLUSIONS Both lymph node biopsy and cytological samples were suitable surrogates for EGFR mutation detection in NSCLC compared with tumor tissues, gene status should be detected widely considering the high EGFR mutation rate, and nonsmoking history together with smaller primary tumor size was an independent indicator of EGFR mutation status.