Primary clear cell adenocarcinoma of the lung: a national analysis

Background: Primary clear cell adenocarcinoma of the lung (CCAL) is a rare form of lung cancer with poorly understood clinical features. We sought to investigate the clinicopathological characteristics and independent prognostic factors of primary CCAL. Methods: Overall survival (OS) of patients with CCAL in the National Cancer Database (NCDB) from 2004 to 2017 was compared to lung adenocarcinoma using Kaplan-Meier analysis, multivariable Cox proportional hazards modeling, and propensity score matching. Independent prognostic indicators for patients with CCAL were determined using multivariable Cox proportional hazards analysis. Results: A total of 1,396 CCAL and 462,360 lung adenocarcinoma patients were included in our analysis. When compared to patients diagnosed with lung adenocarcinoma, those diagnosed with CCAL were more likely to be younger, white, reside farther from a hospital, have higher Charlson/Deyo comorbidity condition (CDCC) scores, have private insurance, have T1, N0, M0 status. In unadjusted analysis, patients with CCAL had better survival than those with lung adenocarcinoma, although no significant differences in survival were found between the two groups with multivariable Cox proportional hazards and propensity score-matched analyses. Conclusions: In this national analysis, we found that the clinicopathological characteristics of CCAL are distinct from those of lung adenocarcinoma, but CCAL is not itself an independent predictor of survival after multivariable adjustment or propensity score-matched analysis.