Abstract 4504: Retrospective study of clinicopathologic factors associated with ALK rearrangement and survival outcome in Chinese patients with NSCLC

Abstract

Background: ALK rearrangement and EGFR mutation are significant molecular subtypes of non-small cell lung cancer (NSCLC) that are targets for different tyrosine kinase inhibitors (TKIs). We tested a large cohort of NSCLC patients for ALK, EGFR and KRAS abnormalities and correlated clinical factors with the ALK fusion gene and overall survival (OS). Methods: ALK status was detected by RACE sequencing; EGFR and KRAS status were also detected by direct DNA sequencing. OS was estimated by the Kaplan-Meier method. Results: 294 consecutive, unselected, banked NSCLC cases were tested; 27 (9.2%), 79 (29.2%) and 26 (9.6%) patients were ALK-, EGFR- and KRAS-positive, respectively. ALK rearrangement and EGFR mutation were largely exclusive (r=−0.15, P=0.007) although two cases were both ALK- and EGFR-positive. In non-parametric tests, ALK-positivity was associated with female gender (χ2=5.189; P=0.023), non/light-smoking (χ2=6.067; P=0.014) and adenocarcinoma (χ2=4.301; P=0.038). The ALK fusion partner was EML4 in all 27 cases; EML4-ALK fusion variants V1, V2 and V3 (V3a/V3b/V3c) made up the majority (24/27) of EML4-ALK fusions. There were no significant OS differences between ALK-positive, EGFR-mutant, KRAS-mutant and triple-negative groups, between ALK-positive and -negative patients, or when ALK-positive cases were matched 1:2 or 1:1 with (non-TKI-treated) controls balancing for disease stage, gender, histology and EGFR/KRAS status. In ALK-positive patients, bivariate analysis found that non- or light-smoking status (P=0.016) and prior surgery (P=0.024) were associated with increased OS and a multivariate Cox regression model found that disease stage and surgical treatment were prognostic for OS. In a multivariate logistic regression model, female gender (HR=2.793; P=0.041), wild type EGFR (HR=15.147; P=0.001), non/light-smoking (HR=3.572; P=0.020) and adenocarcinoma (HR=5.713; P=0.024) were significantly associated with ALK-rearrangement. Conclusion: Overall, the ALK fusion gene occurred in 9.2% of NSCLC patients, and was associated with non/light-smoking history, adenocarcinoma histology and female gender. ALK fusion variants were mostly V1-3, which may inform ALK screening by RT-PCR. ALK rearrangement was not a favorable prognostic factor in NSCLC, although smoking history may influence OS in ALK-positive patients. A TKI (crizotinib) now exists for ALK-positive NSCLC and may improve OS in these patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4504. doi:1538-7445.AM2012-4504

Real-World Outcomes in Patients with Alk-Positive Non-Small Cell Lung Cancer Treated with Crizotinib

“…While some previous research (Zhang et al 24 , for example) has shown no survival difference in metastatic nsclc by alk status (after adjustments for initial disease stage, histology, and egfr/kras mutation), a majority of studies (including a recent review article by Kulig et al 25 ) have reported a poorer survival prognosis for patients with alk-mutated (vs. wild type) tumours independent of alk-inhibitor treatment. Further research is needed, however, to more fully clarify the role of alk rearrangement independent of treatments on the survival prognosis of patients with metastatic nsclc.…”

Crizotinib for the Treatment of ALK-Rearranged Non-Small Cell Lung Cancer: A Success Story to Usher in the Second Decade of Molecular Targeted Therapy in Oncology

“…In two separate reports [65, 95], Shaw et al did not demonstrate any significant differences in overall survival (OS) for patients with NSCLC by EML4-ALK status in the era before crizotinib. Similarly, Zhang et al reported no survival difference according to ALK status after adjusting for disease stage, histology, and EGFR/KRAS mutant status [101]. Lee et al showed that patients with ALK-rearranged NSCLC had the shortest overall survival compared to wild-type patients, but the difference was not significant [102].…”