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controversies regarding the appropriate operative strategy for radiological invasive lung cancer. In particular, as introduced in many times in this lecture, radiological pure-solid lung cancer without GGO component shows aggressive invasive nature, and we have reported the higher frequencies of locoregional recurrence after segmentectomy for clinical-stage IA radiological pure-solid lung cancer40, 41). With regard to the proper operative modes for peripherally located small-sized lung cancer, the result of randomized trial of segmentec-tomy compared to lobectomy is awaited, however the indication of segmentectomy or limited surgical resection for radiological pure-solid tumor should be in great caution from the point of cancer control.In this lecture, we demonstrated the latest clin-ical evidence and the operative strategies for small-sized lung cancers. In early-stage lung cancer, it has been clarified that the presence of a GGO is strongly contributed to the oncological aggressiveness and prognosis. This indicates that not a solid component, but a presence of GGO in itself is a matter of concern regarding the prog-nosis of small-sized lung cancers. Based on the clin-ical evidences, lung adenocarcinoma with a GGO component is deemed as a favorable clinicopatho-logic subgroup different from the pure-solid tumor. Clinical T staging should be classified based on the presence of a GGO, and tumor size be applied only to the radiological solid tumor. With regard to the operative strategies for small-sized lung cancer, it is awaited the result of randomized trial of segmen-tectomy compared to lobectomy in radiologically invasive small-sized lung cancer, however, it should be fully deliberate regarding the indication of limited surgical resection for radiological pure-solid tumor.Not applicable.This work was supported in part by a Grant-in-Aid for Cancer Research from the Ministry of Health, Labour and Welfare, Japan, the Smoking Research Foundation, and the National Cancer Center Research and Development Fund (26-A-4).57Appropriate operative strategy for small-sized lung cancersToday, standard operative mode for resectable lung cancer is recognized as lobectomy, this is based on the evidence from USA in 199537). This randomized trial evaluated the OS of lobectomy and limited resection for clinical T1 non-small cell lung cancer. As shown in the report by Lung Cancer Study Group, lobectomy conferred limited or sublobar resection in both overall survival and recurrence-free survival (RFS). And the rate of locoregional recurrence of limited resection was 3-times higher than lobectomy. Hence, it is consid-ered that the great caution is needed to indicate the limited pulmonary resection for lung cancer. However, due to the advancement of thin-section CT scan, more and more small-sized lung cancer was detected. Furthermore, based on the radiolog-ical and pathological correlations, we can predict pathologically less invasive tumor based on the radiological features. Currently, one of the most important prognostic factors would be a presence or absence of a GGO component, as presented in this lecture. Hence, it is possible to change the para-digm of standard operative strategy in a future16).Here, I would like to introduce 2 important trials conducted in Japan. These studies have been performed by JCOG lung cancer study group. The first trial presents a phase II study to evaluate the feasibility of wide wedge resection for GGO-domi-nant lung cancer, JCOG0804 trial38). The second trial present a phase III study to evaluate the survival outcomes between segmentectomy and lobectomy for radiologically invasive lung cancer39). At first, with regard to the feasibility study to eval-uate the wedge resection for GGO-dominant or less invasive lung cancer, the 5y-RFS was 99.7%, which was quite excellent result38). Hence, it is considered that the sublobar resection, preferably wedge resection, is enough for GGO-dominant lung cancer. Furthermore, the result of survival outcome for radiologically invasive lung cancer will be disclosed near future. We should carefully await this random-ized trial of segmentectomy compared to lobectomy in radiologically invasive small-sized lung cancer to consider the appropriate operative modes of small-sized peripherally located NSCLC. However, at the standpoint of tumor invasiveness, there exist several ConclusionsAcknowledgmentsFunding