Retrospective Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 14, 2015; 21(38): 10883-10889
Published online Oct 14, 2015. doi: 10.3748/wjg.v21.i38.10883
Geographical distribution of the incidence of gastric cancer in Bhutan
Tashi Dendup, James M Richter, Yoshio Yamaoka, Kinley Wangchuk, Hoda M Malaty
Tashi Dendup, Department of Surgery, Jigme Dorji Wangchuck National Referral Hospital, Thimphu, Bhutan
James M Richter, Massachusetts General Hospital, Harvard Medical School, MGH Gastroenterology Associates, Harvard University, Boston, MA 02114, United States
Yoshio Yamaoka, Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu 879-5593, Japan
Kinley Wangchuk, Microbiology Unit, Department of Laboratory Medicine, Jigme Dorji Wangchuck National Referral Hospital, Thimphu, Bhutan
Hoda M Malaty, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, United States
Author contributions: Dendup T and Malaty HM contributed equally to this work; Malaty HM and Dendup T designed research; Malaty HM, Richter JM, Yamaoka Y and Wangchuk K performed research and contributed new reagents/analytic tools; and Malaty HM analyzed data and wrote the paper.
Supported by The Center for Eye Research and Education, Boston Massachusetts (partly).
Institutional review board statement: The project was approved by National Referral Hospital, Thimphu.
Informed consent statement: This is a retrospective Study used data for the analysis.
Conflict-of-interest statement: There is no any conflict of interest to any of the contributed authors.
Data sharing statement: Excel file of data is attached.
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: Hoda M Malaty, MD, PhD, Department of Medicine, Baylor College of Medicine, Houston, Veterans Affairs Medical Center (111D), 2002 Holcombe Blvd., Houston, TX 77030, United States. hmalaty@bcm.edu
Telephone: +1-713-7950232
Received: March 22, 2015
Peer-review started: March 23, 2015
First decision: April 23, 2015
Revised: May 9, 2015
Accepted: August 31, 2015
Article in press: August 31, 2015
Published online: October 14, 2015
Processing time: 205 Days and 23.3 Hours
Abstract

AIM: To estimate the prevalence of gastric cancer (GC) in a cohort of patients diagnosed with GC and to compare it with patients diagnosed with all other types of gastro-intestinal (GI) cancer during the same period.

METHODS: Between 2008 and 2013, five-year period, the medical records of all GI cancer patients who underwent medical care and confirm diagnosis of cancer were reviewed at the National Referral Hospital, Thimphu which is the only hospital in the country where surgical and cancer diagnosis can be made. Demographic information, type of cancer, and the year of diagnosis were collected.

RESULTS: There were a total of 767 GI related cancer records reviewed during the study period of which 354 (46%) patients were diagnosed with GC. There were 413 patients with other GI cancer including; esophagus, colon, liver, rectum, pancreas, gall bladder, cholangio-carcinoma and other GI tract cancers. The GC incidence rate is approximately 0.9/10000 per year (367 cases/5 years per 800000 people). The geographic distribution of GC was the lowest in the south region of Bhutan 0.3/10000 per year compared to the central region 1.4/10000 per year, Eastern region 1.2/10000 per year, and the Western region 1.1/10000 per year. Moreover, GC in the South part was significantly lower than the other GI cancer in the same region (8% vs 15%; OR = 1.8, 95%CI: 1.3-3.1, P = 0.05). Among GC patients, 38% were under the age of 60 years, mean age at diagnosis was 62.3 (± 12.1) years with male-to-female ratio 1:0.5. The mean age among patients with all other type GI cancer was 60 years (± 13.2) and male-to-female ratio of 1:0.7. At time of diagnosis of GC, 342 (93%) were at stage 3 and 4 of and by the year 2013; 80 (23%) GC patients died compared to 31% death among patients with the all other GI cancer (P = 0.08).

CONCLUSION: The incidence rate of GC in Bhutan is twice as high in the United States but is likely an underestimate rate because of unreported and undiagnosed cases in the villages. The high incidence of GC in Bhutan could be attributed to the high prevalence of Helicobacter pylori infection that we previously reported. The lowest incidence of GC in Southern part of the country could be due to the difference in the ethnicity as most of its population is of Indian and Nepal origin. Our current study emphasizes on the importance for developing surveillance and prevention strategies for GC in Bhutan.

Keywords: Gastric cancer; Mortality; Epidemiology; Bhutan

Core tip: The incidence rate of gastric cancer (GC) in Bhutan is twice as high in the United States but is likely an underestimate rate because of unreported and undiagnosed cases in the villages. The high incidence of GC in Bhutan could be attributed to the high prevalence of Helicobacter pylori infection that we previously reported. The lowest incidence of GC in Southern part of the country could be due to the difference in the ethnicity as most of its population is of Indian and Nepal origin. Our current study emphasizes on the importance for developing surveillance and prevention strategies for GC in Bhutan.