Segmental lung resection and wedge lung resection are both sublobar resection procedures, which have been frequently used in recent years for the treatment of early-stage lung cancer. To characterize clinical stage IA lung adenocarcinoma with predominantly ground glass shadows (GGO) and to assess the prognosis of such patients after sublobar resection, Morihito Okada and colleagues from the Department of Surgical Oncology, Hiroshima University, Japan, conducted a study published online in the August 8, 2013 issue of CHEST. The study showed that stage IA lung adenocarcinoma with “predominantly ground glass shadows” is a group of less malignant tumors with a better prognosis. These T1a and T1b patients can be successfully treated with wedge resection and segmental lung resection, respectively. The study is a multicenter clinical study of 610 patients with clinical stage IA lung adenocarcinoma. All patients underwent and completed tumor resection; all underwent preoperative high-resolution CT and f-18-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT). The investigators defined “predominantly glassy tumor” as a tumor with >50% glassy shadow component. In this study, 239 patients (39.2%) met the criteria by preoperative examination. The main findings of the study were that “predominantly glassy” lung adenocarcinoma is less aggressive pathologically and has few lymphatic metastases, hematogenous metastases, pleural infiltrates, or lymph node metastases. The three-year recurrence-free survival rates (RFS) after lobectomy, segmental resection, or wedge resection were 96.4%, 96.1%, and 98.7%, respectively, with no significant differences between groups. In addition, the three-year recurrence-free survival rates after lobectomy, segmental resection, or wedge resection were similar for patients with “predominantly ground glass” stage T1b lung adenocarcinoma, 93.7% versus 92.9% versus 100%, respectively. Of the 84 patients (2.4%) with “predominantly ground glass shadows” in stage T1b lung adenocarcinoma, a total of 2 had lymph node metastases. Multivariate Cox regression analysis showed no effect of tumor size, maximum standardized uptake value at FDG-PET/CT, or surgical procedure on recurrence-free survival in patients with “predominantly ground-glass shadows” lung adenocarcinoma.