作者：广东省肺癌研究所 杨学宁 & LAMP

JCOG0201研究中临床IA期非小细胞肺癌GGO成分的预后评价

157. Validation Study to Evaluate the Prognostic Impact of the Presence of a Ground Glass Opacity Component in Clinical Stage IA Non-Small Cell Lung Cancer: Supplementary Analysis of Japan Clinical Oncology Groups Trial, JCOG0201

Aritoshi Hattori1, *Kenji Suzuki1, Kazuya Takamochi1, Teruaki Koike2, Masashi Wakabayashi3, Keiju Aokage4, Hisashi Saji5, Hiroshige Yoshioka6, Yoshitaka Zenke7, Yasuhiro Tsutani8, Hiroyuki Ito9, Tadashi Aoki2, Kazuo Nakagawa10, Jiro Okami11, *Morihito Okada8, Yuya Sato3, Tomonori Mizutani3, Shun-ichi Watanabe10
1Juntendo University, Tokyo, Japan;2Niigata Cancer Center Hospital, Niigata, Japan; 3JCOG Data Center, National Cancer Center Hospital, Tokyo, Japan;4National Cancer Center Hospital East, Chiba, Japan; 5St. Marianna University, Kanagawa, Japan; 6Kansai Medical University Hospital, Osaka, Japan;7Tokyo Metropolitan Cancer and Infectious Disease Center, Tokyo, Japan;8Hiroshima University, Hiroshima, Japan;9Kanagawa Cancer Center, Kanagawa, Japan; 10National Cancer Center Hospital, Tokyo, Japan;11Osaka International Cancer Institute, Osaka, Japan

Invited Discussant: Peter Licht

Objective: The clinical T staging of lung cancer in the 8th edition of the UICC TNM staging system was determined according to the solid component size, excluding a ground glass opacity (GGO) component. However, there is no consensus on the measurements of solid component in many part-solid tumors due to the several radiologic findings in which the solid component size is quite difficult or impossible to measure. In contrast, we have reported a new and simple fact that presence of a GGO denotes a great influence on the favorable prognosis of non-small cell lung cancer (NSCLC), and a solid component is not considered for the prediction of long-term survival of NSCLC if the tumors show a GGO (Hattori A, Suzuki K, Takamochi K, et al. JTCVS2017;154:2102-10). Hence, we performed a validation study to confirm the prognostic importance of the presence of a GGO based on the long-term follow up data of JCOG0201 which was a prospective study to predict pathological non-invasive lung adenocarcinoma in Japan. 
  Methods: Among the 811 patients registered in JCOG0201, 671 were eligible by an appropriate study monitoring and an adequate central review of thin-section computed tomography (CT). Registered c-stage IA NSCLC was less than 30 mm in maximum tumor size, which was classified into GGO group or Solid group based on the presence of a GGO component on thin-section CT. Based on the solid component size, T staging was reassigned in accordance with the 8th edition TNM staging system of the c-T category. Clinicopathological characteristics were compared between the two study groups. Overall survivals (OS) were estimated using the Kaplan-Meier method. 
Results: Of the cases, 432 (64%) were GGO group, and 239 (36%) were Solid group with a median follow-up time of 10.1y. Solid group showed higher ratio of nodal metastasis (17% vs. 2%), pleural (32% vs. 7%), lymphatic (37% vs. 9%) or vascular invasion (36% vs. 7%) compared to those of the GGO group. Most of the GGO group revealed adenocarcinoma (99%), while several other histological types were found in the Solid group including 8% of non-adenocarcinoma. The 5y-OS was significantly different between GGO and Solid group in c-stage IA NSCLC (95.1% vs. 81.1%, log-rank test p<0.001). Furthermore, the 5y-OS were excellent despite the solid component size among the GGO group (c-T1a or less (n=215): 97.2%, c-T1b (n=181): 93.4%, c-T1c (n=36): 91.7%, Fig. 1a). In contrast, the prognostic impact of the tumor size was definitive in the Solid group (c-T1a (n=8): 87.5%, c-T1b (n=136): 85.9%, c-T1c (n=95): 73.7%, Fig. 1b). 
  Conclusions:The favorable prognostic impact of the presence of a GGO component was confirmed in the JCOG0201 dataset. Lung cancer with a GGO component is considered as a different oncological category from the solid tumor without a GGO. Hence, the presence or absence of a GGO should be considered as an important T parameter in the next clinical T classification.