Outcomes of KRAS mutated, EGFR mutated, ALK mutated and wildtype patients in non-small cell lung cancer brain metastases.

Abstract

e21028 Background: Non-small cell lung cancer (NSCLC) is the most common primary tumor leading to brain metastases. Multiple genetic markers have been profiled in NSCLC patients for potential targeted therapies. EGFR is mutated in up 50% of NSCLCs, while ALK is mutated in around 4-7%. KRAS is the most commonly overexpressed marker, seen in up to 85% of all lung cancers. In this retrospective study, we evaluated the overall survival (OS) and progression-free survival (PFS) between NSCLCBM patients with KRAS mutations, ALK mutations, EGFR mutations, and wildtype. Methods: NSCLCBM patients diagnosed between 2010 and 2019 were analyzed. We collected information regarding molecular marker status, systemic therapies, and date of progression. We defined OS as the date of diagnosis of brain metastases to the date of last follow-up or death. OS and PFS were estimated by the Cox proportional model. Results: We found a total of 2989 NCSLCBM patients, 184 were KRAS mutated, 68 had an ALK gene rearrangement, 184 were EGFR mutated, and 1469 were wildtype. The respective median age was 64.3 years, 64.5 years, 58.2 years, and 64.2 years. Females made up 61.8% of KRAS-positive, 51.8% of ALK-positive, 63% of EGFR-positive, and 46.4% of wildtype patients. The median OS (mOS) in patients who were KRAS-positive, ALK-positive, EGFR-positive, and wildtype were 43.3 months, 119.2 months, 57.9 months, and 33.1 months, respectively. The median PFS (mPFS) for the same cohort was 38.0 months, 112.4 months, 55.3 months, and 30.5 months, respectively. ALK-positive patients showed statistically significant mOS (p-value (p) < 0.001) and mPFS (p = 0.002) when compared to EGFR-positive, KRAS-positive, and wildtype patients. Conclusions: Molecular mutations serve as both prognostic predictors and alternative targeted therapies for NSCLCBM treatment. Our retrospective study showed improved mOS and mPFS in NSCLCBM patients with ALK rearrangements when compared to patients with EGFR mutations, KRAS mutations, and the wildtype. While these results looked at patient outcomes with specific tumor markers, further investigation needs to be done regarding outcomes of specific therapies in each cohort, as well as, intracranial lesion response.