Background: Segmentectomy for small-sized stage Ia non-small cell lung cancer (NSCLC) may be comparable to lobectomy regarding prognosis and local recurrence. However, the clinical results of wedge resection for such patients are still under debate. In this international multicenter study, we retrospectively studied surgical outcomes of sublobar resections for patients with small-sized stage Ia adenocarcinoma to elucidate whether wedge resection is inferior to segmentectomy for such patients. Methods: Between March 2000 and August 2011, 173 patients underwent segmentectomy (group I), and 181 patients underwent wedge resection (group II) at three institutions in Japan and China. The tumor was defined as Ground glass opacity (GGO) type when the proportion of GGO was equal or more than 50% in HRCT, while solid type was defined as the proportion of GGO less than 50%. Clinicopathologic factors, local recurrence rate, and survival were compared. Results: The two groups were similar in sex, comorbidity rate, and composition of Noguchi type. There was no in-hospital death. Postoperative morbidity rate of group I was significantly higher than that of group II (11.0% vs. 2.2%, P < 0.016). Local recurrence rates were similar between group I (4.0%) and group II (4.4%), while no patient with GGO type tumors had local recurrence. Overall and lung cancer-specific survivals were of no significant difference between the two groups. Lung cancer-specific survival rates at 10 years were significantly better in patients with GGO type tumors than in those with solid type tumors (100% vs. 76.9%, P < 0.001). In multivariate Cox regression analyses of lung cancer-specific survival of all patients, GGO type turned out to be an independent prognostic factor, while extent of resection did not have any influence. Conclusions: Our data suggests that sublobar resection is an acceptable procedure for small lung adenocarcinomas without nodal involvement, and wedge resection may not be inferior to segmentectomy for small GGO type tumors. Our study also demonstrates that GGO type is an independent prognostic factor of disease-free survival for small-sized (diameter < 2.0 cm) stage Ia lung adenocarcinomas.
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