Clear cell adenocarcinoma of the lung: a population-based study.

Abstract

BackgroundClear cell adenocarcinoma of the lung (CCAL) is a rare diagnosis with poorly understood clinicopathological characteristics and disease progression.MethodsA population cohort study was conducted using prospectively extracted data from the Surveillance, Epidemiology and End Results database for patients with histological diagnoses of CCAL. Propensity-matched analysis was performed for survival analysis.ResultsA total of 1,203 patients with CCAL were included. The median overall survival (OS) for all patients was 19.0 months (95% CI 16.0–22.0 months). Data for 1-, 3-, and 5-year OS were 58.7, 37.3, and 27.7%, respectively. Log-rank analysis showed that the prognoses of CCAL patients were better than those with non-CCAL adenocarcinoma after propensity-matched analysis (P<0.001). Cancer-directed surgery significantly improved median OS by almost 40 months (45.0 vs 5.0 months; P<0.01). Radiotherapy after surgery prolonged survival compared with patients who only received surgery (37.0 vs 17.0 months; P<0.01). Multivariate Cox analysis showed that older age (>65 years), larger lesions, and lymph node and distant metastases were independent prognostic factors for worse survival, while cancer-directed surgery was an independent protective factor. Five independent prognostic factors were identified and entered into the nomogram. The concordance index of the nomogram for predicting survival was 0.72 (95% CI 0.69–0.74). The calibration curves for the probability of 3-, 5-, and 10-year OS showed optimal agreement between nomogram prediction and actual observation.ConclusionCCAL is a rare pathology, and older age, larger lesions, metastases, and cancer-directed surgery were associated with prognosis. A prognostic nomogram was established to provide individual prediction of OS.