Examining the gastric cancer survival gap between Asians and whites in the United States

Abstract

Background Globally, Asian countries bear a disproportionate gastric cancer burden. Asian Americans, the fastest growing minority population in the US, have higher gastric cancer survival than non-Hispanic whites (NHWs) despite higher incidence. Benefitting from uniform cancer registry standards within the US, we examine for the first time the heterogeneity in the Asian American population, which may elucidate the causes of these disparities. Methods SEER gastric cancer data from 2000 to 2012 were used to calculate 5-year survival estimates for NHWs and the six largest Asian ethnicities. Multivariate analyses were performed to identify critical prognostic factors and survival disparities between Asian groups and NHWs. Results We analyzed 33,313 NHW and 8473 Asian gastric cancer cases. All Asian groups had significantly higher 5-year survival than NHWs, at 29.8%. Among Asians, Koreans and Vietnamese had the highest and lowest survival, at 45.4% and 35.7%, respectively. The Korean survival advantage was largely attributable to relatively high proportions of localized stage and low proportions of cardia tumors. After adjusting for major prognostic factors, the survival disadvantage of NHWs, while attenuated, remained significant in comparison to all Asian groups (HR: 1.33, 95% CI: 1.24-1.43; reference: Korean). The survival disparities within the Asian groups vanished with adjustment. Conclusions This study characterizes distinctive gastric cancer survival patterns among the six major Asian groups and NHWs in the US. The favorable survival for Koreans is largely attributable to specific clinical factors, particularly stage at diagnosis. The causes of the survival disadvantage for NHWs remain elusive.

Comparison of cancer stage distribution in the immigrant and host populations of Norway, 1990–2014

“…The comparison of stage distribution for stomach cancer might be somewhat problematic. Asians have been shown to have a higher proportion of non‐cardia relative to cardia tumors compared to non‐Hispanic Whites in the United States . Not controlling for this might have caused a more favorable stage distribution of stomach cancer in the non‐Western immigrant group in our study.…”

Migration from Mexico to the United States: A high‐speed cancer transition

“…Compared to Mexico, US Mexican populations showed lower mortality for stomach cancer, a malignancy for which the general prognosis remains poor, resulting in uniformly low survival. The lower mortality seen in our study for Mexican Immigrants and Mexican Americans is likely due to lower risk of exposure to chronic Helicobacter pylori infection, a strong stomach cancer risk factor, in the US than in Mexico .…”

“…The age groups were modified for liver cancer to accommodate the known high prevalence of Hepatitis C virus (HCV), a major cause of liver cancer in the birth cohort of 1946-1965 in the US 15 ; resulting groups for liver cancer were ages [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64], and 65 and older. Additionally, for prostate cancer, due to the skewed mortality experience toward older Abbreviations: CI, confidence interval; CUP, cancers of unknown primary, NHL, non-Hodgkin's lymphoma.…”

Differences in cancer survival between immigrants in Norway and the host population

“…Behavioural, cultural and structural factors might all explain such a finding. 31,32 Location of tumours in the cardia is more common in Western countries and associated with worse survival than tumours in the middle or distal location. At a structural level, the healthcare system might provide better services for immigrant groups that has been present for a long period.…”