Biomarker Testing in Patients With Unresectable Advanced or Recurrent Non–Small Cell Lung Cancer

Importance Biomarker testing for driver mutations is essential for selecting appropriate non–small cell lung cancer (NSCLC) treatment but is insufficient. Objective To investigate the status of biomarker testing and drug therapy for NSCLC in Japan for identifying problems in treatment. Design, Setting, and Participants The REVEAL cohort study included retrospective data collection and prospective follow-up from 29 institutions across Japan. Of 1500 patients diagnosed with advanced or recurrent NSCLC between January 1 and March 18, 2021, 1479 were eligible. Cases recognized at the wrong clinical stage (n = 12), diagnosed outside the study period (n = 6), not treated according to eligibility criteria before recurrence (n = 2), and with deficient consent acquisition procedure (n = 1) were excluded. Main Outcomes and Measures The primary end point was the biomarker testing status. Treatment-related factors were examined. Results Among the 1479 patients included in the analysis, the median age was 72 (range, 30-95) years; 1013 (68.5%) were men; 1161 (78.5%) had an Eastern Cooperative Oncology Group performance status 0 or 1; 1097 (74.2%) were current or past smokers; and 947 (64.0%) had adenocarcinoma. Biomarker status was confirmed in 1273 patients (86.1%). Multigene testing was performed in 705 cases (47.7%); single-gene testing, in 847 (57.3%); and both, in 279 (18.9%). Biomarker testing was performed for EGFR in 1245 cases (84.2%); ALK , in 1165 (78.8%); ROS1 , in 1077 (72.8%); BRAF , in 803 (54.3%); and MET , in 805 (54.4%). Positivity rates among 898 adenocarcinoma cases included 305 (34.0%) for EGFR , 29 (3.2%) for ALK , 19 (2.1%) for ROS1 , 11 (1.2%) for BRAF , and 14 (1.6%) for MET . Positivity rates among 375 nonadenocarcinoma cases were 14 (3.7%) for EGFR , 6 (1.6%) for ALK , 1 (0.3%) for ROS1 , 3 (0.8%) for BRAF , and 8 (2.1%) for MET . Poor physical status, squamous cell carcinoma, and other comorbidities were associated with hampered multigene testing. Targeted therapy was received as first-line treatment by 263 of 278 cases (94.6%) positive for EGFR , 25 of 32 (78.1%) positive for ALK , 15 of 24 (62.5%) positive for ROS1 , 9 of 12 (75.0%) positive for BRAF , and 12 of 19 (63.2%) positive for MET . Median overall survival of patients with positive findings for driver gene alteration and who received targeted therapy was 24.3 (95% CI, not reported) months; with positive findings for driver gene alteration and who did not receive targeted therapy, 15.2 (95% CI, 7.7 to not reported) months; and with negative findings for driver gene alteration, 11.0 (95% CI, 10.0-12.5) months. Multigene testing for nonadenocarcinomas and adenocarcinomas accounted for 705 (47.7%) of all NSCLC cases. Conclusions and Relevance These findings suggest that multigene testing has not been sufficiently implemented in Japan and should be considered prospectively, even in nonadenocarcinomas, to avoid missing rare driver gene alterations.