Evidence-Based Medicine
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 14, 2015; 21(2): 667-674
Published online Jan 14, 2015. doi: 10.3748/wjg.v21.i2.667
Biopathologic features and clinical significance of micrometatasis in the lymph node of early gastric cancer
Min Jung Jo, Ji Yeon Park, Joon Seon Song, Myeong-Cherl Kook, Keun Won Ryu, Soo-Jeong Cho, Jun Ho Lee, Byung-Ho Nam, Eun Kyung Hong, Il Ju Choi, Young-Woo Kim
Min Jung Jo, Ji Yeon Park, Myeong-Cherl Kook, Keun Won Ryu, Soo-Jeong Cho, Jun Ho Lee, Il Ju Choi, Young-Woo Kim, Gastric Cancer Branch, Research Institute and Hospital, National Cancer Center, Goyang-si 410-769, South Korea
Joon Seon Song, Eun Kyung Hong, Department of Pathology, Research Institute and Hospital, National Cancer Center, Goyang-si 410-769, South Korea
Byung-Ho Nam, Cancer Registration and Biostatistics Branch and Center for Clinical Trial, National Cancer Center, Goyang-si 410-769, South Korea
Author contributions: Jo MJ and Park JY contributed equally to this work; Ryu KW designed the research; Jo MJ, Song JS, Cho SJ, Lee JH, Choi IJ and Kim YW performed the research; Ryu KW, Kook MC, Hong EK and Nam BH analyzed the data; Ryu KW, Jo MJ and Park JY wrote the paper.
Supported by Grants from the National Cancer Center, Republic of Korea, Grant No. 0910560-1 and No. 1010490-1.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Eun Kyung Hong, MD, Department of Pathology, Research Institute and Hospital, National Cancer Center, 809 Madu1-dong, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, South Korea. hongek@ncc.re.kr
Telephone: +82-31-9201628 Fax: +82-31-9200069
Received: June 12, 2014
Peer-review started: June 13, 2014
First decision: July 9, 2014
Revised: July 16, 2014
Accepted: July 24, 2014
Article in press: July 25, 2014
Published online: January 14, 2015
Abstract

AIM: To evaluate the biopathologic features and clinical significance of nodal micrometastasis (MI) in early gastric cancer (EGC).

METHODS: Among 1022 EGC patients who underwent gastrectomy with lymphadenectomy of D1 + β or more from March 2001 to December 2005 at the Korean National Cancer Center, available nodal metastasis was found in 90 pT1N1 patients. Nodal metastasis was confirmed by immunohistochemistry (IHC) with cytokeratin and patients were classified into MI and macrometastasis (MA) groups based on the main tumor burden according to the 6th International Union Against Cancer/American Joint Committee on Cancer staging system; the main tumor burden with a diameter of greater than 0.2 mm but no greater than 2 mm as MI, and greater than 2 mm as MA of the representative metastatic node. Proliferative and apoptotic activities of the primary tumor and the nodal metastasis were measured by IHC with Ki-67 and terminal deoxynucleotidyl transferase dUTP nick end labeling, respectively. Biopathologic and clinical features of the patients were analyzed and compared between MI and MA groups. Patients with recurrence were compared with those without recurrence to identify risk factors for recurrence.

RESULTS: Thirty-seven patients showed MI and the other 53 patients revealed MA in the lymph node; the incidence of patients with MI and MA was 41.1% and 58.9%. The main tumor burden was 0.9 and 4.6 mm in the representative metastatic node, respectively. Japanese N2 stations were more frequently involved in MA group (20.9%) than in MI group (10.3%) but the difference was not statistically different (P = 0.338). Proliferative and apoptotic activities of MI were decreased than those of MA (26.7% vs 40.5%, P = 0.004 and 1.0% vs 3.0%, P < 0.001, respectively). However, nodal MI in the current study showed a relatively high proliferative activity and an equivalent apoptotic activity compared to other cancers in the previously published studies. Recurrence was observed in 6 patients during the mean follow up period of 87.6 ± 26.2 mo. The recurrence was significantly associated with the presence of MA (P = 0.041) and lymphovascular invasion of the primary tumor (P = 0.032).

CONCLUSION: Lymphadenectomy of D1 + β or more might be necessary in patients with MI in sentinel node to prevent recurrence by clearing MI involving Japanese N2 station.

Keywords: Early gastric cancer, Sentinel node biopsy, Lymphadenectomy, Micrometastasis, Macrometastasis

Core tip: Nodal micrometastasis in early gastric cancer (EGC) has a relatively high proliferative and an equivalent apoptotic activities compared to other cancers. The incidence of Japanese N2 station micrometastasis involvement is about 10%. Lymphadenectomy of D1+β or more might be necessary if micrometastasis is identified during sentinel node biopsy in EGC.