Retrospective Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 7, 2018; 24(25): 2722-2732
Published online Jul 7, 2018. doi: 10.3748/wjg.v24.i25.2722
Gastric cancer in Alaska Native people: A cancer health disparity
Holly A Martinson, Nancy J Shelby, Steven R Alberts, Matthew J Olnes
Holly A Martinson, Nancy J Shelby, WWAMI School of Medical Education, University of Alaska Anchorage, Anchorage, AK 99508, United States
Steven R Alberts, Department of Oncology, Mayo Clinic Cancer Center, Rochester, MN 55905, United States
Matthew J Olnes, Hematology and Medical Oncology Department, Alaska Native Medical Center, Anchorage, AK 99508, United States
Author contributions: Martinson HA, Shelby NJ, Alberts SR and Olnes MJ designed the research study; Martinson HA performed the research; Martinson HA analyzed the data; Martinson HA, Shelby NJ, Alberts SR, and Olnes MJ wrote the manuscript.
Supported by the Debbie’s Dream Foundation-AACR Gastric Cancer Research Fellowship, No. 16-40-41-MART (to Martinson HA); and an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health (NIH), No. P20GM103395 (to Martinson HA, Shelby NJ and Olnes MJ). The content is solely the responsibility of the authors and does not necessarily reflect the official views of the NIH.
Institutional review board statement: This study was reviewed and approved by the University of Alaska Anchorage Institutional Review Board (IRB), Alaska Area IRB, Southcentral Foundation Research Review Board, and the Alaska Native Tribal Health Consortium Health Research Review Committee.
Informed consent statement: Patients were not required to give informed consent to this study because the analysis used anonymous clinical data that were obtained after each patient agreed to treatment by written consent.
Conflict-of-interest statement: The authors have no conflicting financial 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: Holly A Martinson, PhD, Assistant Professor, WWAMI School of Medical Education, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, AK 99508, United States.
Telephone: +1-907-7864672 Fax: +1-907-7864700
Received: March 31, 2018
Peer-review started: April 2, 2018
First decision: April 19, 2018
Revised: May 9, 2018
Accepted: June 2, 2018
Article in press: June 2, 2018
Published online: July 7, 2018
Research background

Gastric cancer is a leading cancer health disparity among the Alaska Native (AN) people, with a 3-fold higher incidence and mortality rate compared to United States non-Hispanic White (NHW) people. There are currently a paucity of studies investigating the clinicopathologic features of this disease in AN people, and their relationship to clinical outcomes.

Research motivation

This study was conducted to gain a deeper understanding of AN gastric cancer patient characteristics, pathologic variables, clinical patterns of care, and patient outcomes to gain insights into to this cancer health disparity.

Research objectives

In order to further investigate how to reduce gastric cancer incidence and mortality rates among the AN population, we sought to evaluate recent trends in gastric cancer incidence, response to treatment, and overall survival outcomes in this high incidence population. A greater understanding of gastric cancer incidence and response to treatment among the AN people may facilitate the design of screening programs or the identification of early detection measures, and elucidate new areas for future investigation to potentially reduce incidence and improve patient outcomes.

Research methods

We performed a retrospective analysis of 132 AN gastric cancer patients treated at the Alaska Native Medical Center (ANMC) from 2006-2014, utilizing the ANMC Tumor Registry and manual patient chart reviews. We compared our findings to data on United States (US) NHW and AN gastric adenocarcinoma patients obtained from the US National Institute’s SEER Program of the National Cancer Institute 18 dataset for the period 2006-2014. Data were analyzed using software SPSS 23.0.

Research results

AN patients differ from NHW patients in that they have a higher prevalence of non-cardia tumors, unique histological features with a higher incidence of the diffuse subtype, and a higher incidence of signet ring cell carcinomas. AN females were more likely to be diagnosed with stage IV cancers compared to AN males. We observed a decreased overall survival among AN patients with advanced stage disease, O+ blood type, < 15 lymph nodes examined at resection, and no treatment. AN gastric cancer patients have a higher incidence rate, a poorer overall survival, and are diagnosed at a significantly younger age compared to NHW patients. This study is the first report detailing the clinicopathologic features of gastric cancer in AN people, as well as information on patterns of care, and clinical outcome data.

Research conclusions

Gastric cancer in AN people is distinct from the NHW population. AN patients were observed to have increased incidence, poorer prognosis, earlier age of diagnosis, and variation in location, and histological subtype of gastric cancer. These clinicopathological characteristics could be driven by multiple variables including, socioeconomic factors and biological differences, such as lifestyle differences, genetic alterations, and environmental exposures. Our findings confirm the importance of early detection, treatment, and surgical resection for AN patients with resectable gastric adenocarcinoma in order to optimize patient outcomes. This study highlights the need for further investigation into understanding the basis for the increased incidence and poorer prognosis of this devastating cancer in AN people.

Research perspectives

Our work highlights the unique clinical and pathologic features of gastric cancer in the AN population. The high incidence of this cancer warrants prompt referral for endoscopic evaluation of AN patients presenting with gastrointestinal symptoms. Of particular concern is the finding that younger women present more frequently with stage IV disease, emphasizing the need to consider a diagnosis of gastric cancer earlier in this population. Clinical outcomes are poor in this population, despite the fact that patients are treated according to standard guidelines. An important area for future study will be investigations into the molecular features of gastric cancer in AN people, with the goal of identifying new prognostic and predictive markers that may improve treatment regimens, and possibly identify new targets for precision medicine.