Prognostic factors in curatively resected pathological stage I lung adenocarcinoma

Patients with pathological stage I (p I) lung adenocarcinoma show variabilities in prognosis even after complete resection. The factors resulting in heterogeneities of prognosis remain controversy. The aim of this study was to identify the risk factors affecting recurrence/metastasis and survival in patients with curatively resected p I lung adenocarcinoma.

A total of 252 patients with p I lung adenocarcinoma underwent curative resection between January 1st, 2009 to September 30th, 2011 were retrospectively reviewed to analyze the associations of recurrence and survival with the following clinicopathological variables: gender, age, cigarette smoking, family cancer history, tumor size, TNM stage, tumor differentiation, visceral pleural invasion, bronchial involvement, lymphovascular invasion, postoperative adjuvant treatment, pathological subtypes and micropapillary pattern.

Among those 252 patients, 48 had local recurrence or distant metastasis, the rest 204 patients had no relapse until the last follow-up. Cox univariate survival analysis revealed that tumor size (P<0.001), TNM stage [disease-free survival (DFS), P<0.001; overall survival (OS), P=0.004], tumor differentiation (P<0.001), bronchial involvement (P<0.001), lymphovascular invasion (DFS, P=0.021; OS, P=0.001) and micropapillary pattern (DFS, P<0.001; OS, P=0.003) were significantly associated with DFS and OS, while cigarette smoking (P=0.029) and pathological subtypes (P=0.041) were found to be risk factors for DFS either. In multivariate analysis, tumor differentiation (P<0.001) was an independent risk factor for both DFS and OS, TNM stage (P=0.007), bronchial involvement (P=0.004) and micropapillary pattern (P=0.001) only for DFS, while tumor size (P=0.009) and lymphovascular invasion (P=0.010) were found to be independent risk factors only for OS.

Tumor size, TNM stage, tumor differentiation, bronchial involvement, lymphovascular invasion and micropapillary pattern could be considered as risk factors for predicting local recurrence or distant metastasis and survival in curatively resected p I lung adenocarcinoma patients.