Context: - Different testing algorithms and platforms for EGFR mutations and ALK rearrangements in advanced-stage lung adenocarcinoma exist. The multistep approach with single-gene assays has been challenged by more efficient next-generation sequencing (NGS) of a large number of gene alterations. The main criticism of the NGS approach is the detection of genomic alterations of uncertain significance.
Objective: - To determine the best testing algorithm for patients with lung cancer in our clinical practice.
Design: - Two testing approaches for metastatic lung adenocarcinoma were offered between 2012-2015. One approach was reflex testing for an 8-gene panel composed of DNA Sanger sequencing for EGFR, KRAS, PIK3CA, and BRAF and fluorescence in situ hybridization for ALK, ROS1, MET, and RET. At the oncologist's request, a subset of tumors tested by the 8-gene panel was subjected to a 50-gene Ion AmpliSeq Cancer Panel.
Results: - Of 1200 non-small cell lung carcinomas (NSCLCs), 57 including 46 adenocarcinomas and NSCLCs, not otherwise specified; 7 squamous cell carcinomas (SCCs); and 4 large cell neuroendocrine carcinomas (LCNECs) were subjected to Ion AmpliSeq Cancer Panel. Ion AmpliSeq Cancer Panel detected 9 potentially actionable variants in 29 adenocarcinomas that were wild type by the 8-gene panel testing (9 of 29, 31.0%) in the following genes: ERBB2 (3 of 29, 10.3%), STK11 (2 of 29, 6.8%), PTEN (2 of 29, 6.8%), FBXW7 (1 of 29, 3.4%), and BRAF G469A (1 of 29, 3.4%). Four SCCs and 2 LCNECs showed investigational genomic alterations.
Conclusions: - The NGS approach would result in the identification of a significant number of actionable gene alterations, increasing the therapeutic options for patients with advanced NSCLCs.