Frequency of EGFR and KRAS mutations in patients with non small cell lung cancer by racial background: do disparities exist?

Abstract

Introduction: Mutations in EGFR and KRAS can impact treatment decisions for patients with NSCLC. The incidence of these mutations varies, and it is unclear whether there is a decreased frequency among African Americans (AfAs).

Methods: We performed a retrospective chart review of 513 NSCLC patients undergoing EGFR and KRAS mutational analysis at the Hospital of the University of Pennsylvania between May 2008 and November 2011. Clinical and pathologic data were abstracted from the patients' electronic medical record.

Results: Of 497 patients with informative EGFR mutation analyses, the frequency of EGFR mutation was 13.9%. The frequency of EGFR mutations was associated with race (p < 0.001) and was lower in AfA patients compared to Caucasian (C) patients but did not reach statistical significance (4.8% vs. 13.7%, p = 0.06). Mean Charlson Comorbidity Index and number of cigarette pack years were significantly lower in patients with EGFR mutations (p = 0.01 and p < 0.001, respectively). Multivariable logistic regression analysis showed a significant association between race and EGFR mutation (p = 0.01), even after adjusting for smoking status (p < 0.001) and gender (p = 0.03). KRAS mutation (study frequency 28.1%) was not associated with race (p = 0.08; p=0.51 for Afa vs. C patients), but was more common among smokers (p < 0.001) and females (p = 0.01).

Conclusions: Based on multivariable analysis, even after adjusting for smoking status and gender, we found that race was statistically significantly associated with EGFR mutation, but not KRAS mutational status. To the best of our knowledge, this is the largest single institution series to date evaluating racial differences in EGFR and KRAS mutational status among patients with NSCLC.

Keywords: EGFR; KRAS; NSCLC; Racial disparity.