Retrospective Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 21, 2016; 22(15): 4020-4026
Published online Apr 21, 2016. doi: 10.3748/wjg.v22.i15.4020
Risk of lymph node metastasis in mixed-type early gastric cancer determined by the extent of the poorly differentiated component
Chung-Su Hwang, Sangjeong Ahn, Bong-Eun Lee, So-Jeong Lee, Ahrong Kim, Chang In Choi, Dae Hwan Kim, Tae-Yong Jeon, Gwang Ha Kim, Geum Am Song, Do Youn Park
Chung-Su Hwang, Sangjeong Ahn, So-Jeong Lee, Ahrong Kim, Do Youn Park, Department of Pathology, Pusan National University Hospital and Pusan National University School of Medicine, Busan 602-739, South Korea
Bong-Eun Lee, Gwang Ha Kim, Geum Am Song, Internal medicine, Pusan National University Hospital and Pusan National University School of Medicine, Busan 602-739, South Korea
Chang In Choi, Dae Hwan Kim, Tae-Yong Jeon, Surgery, Pusan National University Hospital, Busan 602-739, South Korea
Do Youn Park, Sangjeong Ahn, Biomedical Research Institute, Pusan National University Hospital, Busan 602-739, South Korea
Author contributions: Hwang CS and Ahn S contributed equally to this work; Park DY designed the research; Lee BE, Lee SJ, Kim A, Choi CI, Kim DH, Jeon TY, Kim GH and Song GA performed the research; Park DY and Hwang CS analyzed the data and wrote the paper; Ahn S made critical revisions; Park DY and Ahn S approved the final version of the article.
Supported by A grant from the National R&D Program for Cancer Control, Ministry for Health, Welfare, and Family Affairs, South Korea, No. 0920050.
Institutional review board statement: This study was reviewed and approved by the institutional Review Board of the Pusan National University Hospital (E-2014130).
Informed consent statement: This retrospective study was performed under IRB approval, all data is de-identified for statistical analysis. Therefore, we think that a waiver of informed consent may be justifiable under this situation. The bio-specimens for this study were provided by the Pusan National University Hospital, a member of the National Biobank of South Korea, which is supported by the Ministry of Health, Welfare and Family Affairs. All samples derived from the National Biobank of South Korea were obtained with informed consent under institutional review board-approved protocols.
Conflict-of-interest statement: The authors declare no conflict of interests.
Data sharing statement: No additional data are available.
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:
Correspondence to: Do Youn Park, MD, PhD, Department of Pathology, Pusan National University Hospital and Pusan National University School of Medicine, 1-10 Ami-Dong, Seo-Gu, Busan 602-739, South Korea.
Telephone: +82-51-2407717 Fax: +82-52-2560788
Received: October 20, 2015
Peer-review started: October 22, 2015
First decision: November 27, 2015
Revised: December 2, 2015
Accepted: January 17, 2016
Article in press: January 18, 2016
Published online: April 21, 2016

AIM: To predict the rate of lymph node (LN) metastasis in diffuse- and mixed-type early gastric cancers (EGC) for guidelines of the treatment.

METHODS: We reviewed 550 cases of EGC with diffuse- and mixed-type histology. We investigated the clinicopathological factors and histopathological components that influence the probability of LN metastasis, including sex, age, site, gross type, presence of ulceration, tumour size, depth of invasion, perineural invasion, lymphovascular invasion, and LN metastasis status. We reviewed all slides and estimated the proportions of each tumour component; pure diffuse type, mixed-predominantly diffuse type (diffuse > intestinal type), mixed-predominantly intestinal type (intestinal > diffuse type), and mixed diffuse = intestinal type. We calculated the extents of the respective components.

RESULTS: LN metastasis was observed in 12.9% (71/550) of early gastric cancers cases [15/288 mucosal EGCs (5.2%) and 56/262 submucosal EGCs (21.4%)]. Of 550 cases, 302 were diffuse-type and 248 were mixed-type EGCs. Of 248 mixed-type EGCs, 163 were mixed-predominantly diffuse type, 82 were mixed-predominantly intestinal type, and 3 were mixed diffuse = intestinal type. Mixed-type cases with predominantly diffuse type histology showed a higher frequency of LN metastasis (20.2%) than cases of pure diffuse type (9.3%) and predominantly intestinal type (12.2%) histology. We measured the dimensions of each component (intestinal and diffuse type) to determine the association of the extent of each component with LN metastasis in mixed-type gastric carcinoma. The total tumour size and the extent of poorly differentiated components was associated with LN metastasis, while that of signet ring cell components was not.

CONCLUSION: We recommend careful identification and quantitative evaluation of mixed-type early gastric cancer components after endoscopic resection to determine the intensity of the treatment.

Keywords: Lymph nodes, Metastasis, Gastric cancer, Histology, Endoscopic gastrointestinal surgery

Core tip: This study consolidates correlations between clinicopathological characteristics of early gastric cancer and the risk of lymph node (LN) metastasis, which is important to select patients that will benefit from endoscopic submucosal dissection. This paper also shows that the amount of poorly differentiated tumor cells within mixed type early gastric cancer is correlated with the highest risk of LN metastasis, thus highlighting the need for diligent histological characterization of patient specimens.