Rising Incidence of Non-Cardia Gastric Cancer among Young Women in the United States, 2000-2018: A Time-Trend Analysis Using the USCS Database

Abstract

Introduction: Although the global incidence of non-cardia gastric cancer (NCGC) is decreasing, there are limited data on sex-specific incidence in the United States. This study aimed to investigate time trends of NCGC from the SEER database to externally validate findings in a SEER-independent national database, and to further assess trends among subpopulations.

Methods: Age-adjusted incidence rates of NCGC were obtained from the SEER database from 2000 to 2018. We used joinpoint models to calculate average annual percentage change (AAPC) to determine sex-specific trends among older (≥55 years) and younger adults (15-54 years). Using the same methodology, findings were then externally validated using SEER-independent data from the National Program of Cancer Registries (NPCR). Stratified analyses by race, histopathology, and staging at diagnosis were also conducted in younger adults.

Results: Overall, there were 169,828 diagnoses of NCGC from both independent databases during the period 2000-2018. In SEER, among those <55 years, incidence increased at a higher rate in women (AAPC = 3.22%, p < 0.01) than men (AAPC = 1.51%, p = 0.03), with non-parallel trends (p = 0.02), while a decreasing trend was seen in both men (AAPC = -2.16%, p < 0.01) and women (AAPC = -1.37%, p < 0.01) of the ≥55 years group. Validation analysis of the SEER-independent NPCR database from 2001 to 2018 showed similar findings. Further stratified analyses showed that incidence is disproportionately increasing in young non-Hispanic White women [AAPC = 2.28%, p < 0.01] while remaining stable in their counterpart men [AAPC = 0.58%, p = 0.24] with non-parallel trends (p = 0.04). This pattern was not observed in other race groups.

Conclusion: NCGC incidence has been increasing at a greater rate in younger women compared to counterpart men. This disproportionate increase was mainly seen in young non-Hispanic White women. Future studies should investigate the etiologies of these trends.

Keywords: NPCR database; SEER database; incidence rate trend; non-cardia gastric cancer.

Figure 1

(A) In SEER, among those aged ≥55 years, APC in men is decreasing at a greater rate than in women with non-parallel trends (AAPC −2.44% vs. −1.64%; p-value < 0.01). (B) In SEER, among those aged <55 years, incidence increased in women but remained stable in men (AAPC 2.01% vs. 0.29%; p-value < 0.01). (C,D) In SEER-Independent NPCR, both findings in those of age ≥55 and <55 were similar to the analyses of SEER database.

Figure 2

(A–D) Sex-specific incidence trends among younger adults by race. All data are from SEER database, among those of age < 55 years. Lines of both men and women are same colors if trends are parallel, meaning same APC and AAPC values during the interval years. (A) In Non-Hispanic Whites, APC in women is increasing at a greater rate than in men with non-parallel trends (AAPC 2.28% vs. 0.58%; p-value < 0.04). (B–D) In Non-Hispnanic Blacks, Hispanics, and Asian/Pacific Islanders, incidence trends in women and men were identical but not parallel (p-values 0.06, 0.17, 0.32, respectively).

Figure 3

(A–C) Sex-specific incidence trends among younger adults by histopathology based on Lauren’s criteria. All data are from SEER database, among those of age < 55 years. Lines of both men and women are same colors if trends are parallel, meaning same APC and AAPC values during the interval years. (A,B) Based on Lauren’s criteria, both intestinal and diffuse subtype groups showed parallel incidence trends between men and women (p-values 0.29 and 0.83, respectively). (C) Of the unspecified subtype, women had statistically significant increase in incidence compared to counterpart men in nonparallel trend (AAPC 3.62% vs. 0.43%; p-value < 0.01).

Figure 4

(A–D) Sex-specific incidence trends among younger adults by staging at diagnosis. All data are from SEER database, among those of age < 55 years. Lines of both men and women are same colors if trends are parallel, meaning same APC and AAPC values during the interval years. (A) Among patients with localized stage of disease at diagnosis, women had higher increase in incidence than men (AAPC 5.17% vs. 2.04%; p-value < 0.03). (B–D) Among those with regional, distant, or unknown/unstaged staging at diagnosis, the trends between men and women were parallel (p-values 0.47, 0.94, 0.37, respectively).