Prognostic impact of micropapillary component in patients with node‐negative subcentimeter lung adenocarcinoma: A Chinese cohort study

BACKGROUND: In this study, we investigated the prognostic significance of a micropapillary (MP) component in patients with subcentimeter lung adenocarcinoma. METHODS: A total of 311 patients with subcentimeter lung adenocarcinoma who underwent surgical resection between January 2009 to December 2012 from seven medical centers were included. Recurrence‐free survival (RFS) and overall survival (OS) were analyzed. RESULTS: The five‐year RFS was 79.8% in 97 (97/311, 31%) cases of adenocarcinoma with a MP component and 93.5% in the 214 (214/311, 69%) cases without. In multivariate analysis, MP was an independent risk factor for worse RFS (hazard ratio [HR], 3.73; 95% confidence interval [CI]: 1.87–7.42; P < 0.001) and OS (HR, 5.84; 95% CI: 2.20–15.49; P < 0.001). There was no significant difference among wedge resection, segmentectomy and lobectomy on RFS (P = 0.256) and OS (P = 0.103) in patients without MP. Regarding patients with a MP component, lobectomy achieved equivalent prognosis than segmentectomy, and both were better than wedge resection (P = 0.001). CONCLUSIONS: A MP component still suggest a poor prognosis in subcentimeter lung adenocarcinoma. Patients with subcentimeter lung adenocarcinoma with a MP component of 5% or greater treated with wedge resection were at higher risk of recurrence than patients treated with anatomical resection.