S1625 Primary Gastric Cancer Mortality Rates Are Decreasing in Young Men but Not Young Women in the U.S., 2000-2019: A Population-Based Time-Trend Analysis Using the CDC’s National Center of Health Statistics (NCHS) Database

Abstract

Introduction: Recent data showed that incidence of gastric cancer (GC) has been increasing in the US over the last 2 decades among younger women (< 55 years) at a significantly greater rate compared to younger men. However, the impact of such findings on mortality has not been evaluated. The aim of this study was to investigate sex and age-specific GC mortality rates in the US using CDC’s National Center of Health Statistics (NCHS) database. Methods: The NCHS database is a nationally representative database that covers ≈100% of occurred deaths. For this study, deaths attributed to GC in the US during 2000-2019 were included and mortality rates per 100,000 population were calculated using SEER*Stat software (v8.4.0, NCI). Rates were age-adjusted to the 2000 US population and stratified by sex and age of 2 groups, younger adults (age < 55 years) and older adults. Time trends of mortality rates were estimated using Joinpoint Regression Program (v4.9.0.1, NCI), which utilizes Monte Carlo Permutation analysis to estimate the simplest trend. Annual percentage change (APC) and average APC (AAPC) were calculated. Sex-specific pairwise comparison was conducted for identicalness (test of coincidence) and parallelism (test of parallelism) along with assessing AAPC difference. A 2-sided P-value cutoff of 0.05 was utilized (Table). Results: A total of 230,158 people died of GC during the study period (40.8% women). Overall, GC mortality rates were decreasing in men (AAPC=-2.87, P< 0.001) at a significantly greater rate compared to women (AAPC=-2.34, P< 0.001). Among older adults (195,893 deaths; 40.9% women), GC mortality rates have been decreasing in both men (AAPC=-3,17, P< 0.001) and women (AAPC=-2.89, P< 0.001) without a significant difference. However, among younger adults (34,250 deaths; 40.5% women), GC mortality rates have been decreasing in men (AAPC=-0.97, P< 0.001) but not in women (AAPC=0.01, P=0.93) with an absolute AAPC difference of 0.98 (P< 0.001). The trends were non-identical and non-parallel (both P< 0.001) suggesting that mortality rates among men are decreasing at a significantly greater rate compared to the stable trend among women (1299092, Figure). Conclusion: Nationwide data from the CDC’s NCHS database showed that mortality rates of GC were overall decreasing. However, among younger adults (aged < 55 years), mortality rates were decreasing in men but not in women. Future studies should elucidate risk factors in this population.Figure 1.: Figure: Sex-specific Trends and Age-Adjusted Mortality Rates Per 100,000 Population for Gastric Cancer Among Different Age Groups. A: The average annual percentage change (AAPC) is decreasing in men at a significantly greater rate than in women (-2.87 vs -2.34, P<0.001). B: The AAPC is decreasing in men and women without a significant difference (-3.17 vs -2.89, P=0.07). C: The AAPC is decreasing in men but not in women with a statistically significant difference (-0.97 vs 0.01, P<0.001). Table 1. - Sex-Specific Trends for Gastric Cancer Mortality Among Different Age Groups Age group, y Cancer cases (N=230,158) a Trends b Sex-specific AAPC difference (95% CI) Pairwise comparison P-values Time period APC (95% CI) AAPC (95% CI) Sex-specific AAPC difference Coincidence e Parallelismf All ages Women 93,966 (40.8%) 2000-2006 -3.00 (-3.41 to -2.60) -2.34 (-2.55 to -2.13) -0.53 (-0.83 to -0.24) < 0.001 < 0.001 < 0.001 2006-2019 -1.85 (-2.12 to -1.58) Men 136,192 (59.2%) 2000-2008 -3.64 (-4.21 to -3.06) -2.87 (-3.07 to -2.67) 2008-2019 -2.52 (-2.70 to -2.33) Aged ≥55 Women 80,084 (34.8%) 2000-2007 3.65 (-4.09 to -3.20) -2.89 (-3.08 to -2.69) -0.29 (-0.60 to 0.02) 0.07 < 0.001 < 0.001 2007-2019 -2.44 (-2.65 to -2.23) Men 115,809 (50.3%) 2000-2006 -3.92 (-4.59 to -3.25) -3.17 (-3.41 to -2.93) 2006-2019 -2.83 (-3.04 to -2.61) Aged < 55 # Women 13,874 (6.0%) 2000-2019 0.01 (-0.33 to 0.36) 0.01 (-0.33 to 0.36) -0.98 (-1.34 to -0.63) < 0.001 < 0.001 0.001 Men 20,376 (8.9%) 2000-2019 -0.97 (-1.13 to -0.80) -0.97 (-1.13 to -0.8 aData are presented as death count numbers followed by percentages of the death count numbers from the total cases of cancer deaths in the database.bTime-trends were computed using Joinpoint Regression Program (v4.9.0.1, NCI) with 3 maximum joinpoints allowed (4-line segments).cA negative value indicates a greater AAPC in women compared to men.dTests whether sex-specific trends were identical. A significant P-value indicates that the trends were not identical (i.e., they had different mortality rates and coincidence was rejected).eTests whether sex-specific trends were parallel. A significant P-value indicates that the trends were not parallel (i.e., parallelism was rejected).#Primary outcome.