Epidemiology of Gastric Malignancies 2000-2018 According to Histology: A Population-Based Analysis of Incidence and Temporal Trends

Abstract

Background & aims: Gastric cancer (GC) remains a leading cause of cancer and cancer-related mortality. Recent reports suggest noncardia GC is increasing in certain U.S.

Populations: However, whether these trends are driven by gastric adenocarcinoma (GA) or other histologies, including neuroendocrine tumors (NETs), lymphoma, or gastrointestinal stromal tumors (GISTs), is unclear.

Methods: We analyzed the Surveillance, Epidemiology and End Results-18 cancer registry (2000-2018) to determine age-standardized incidence rates (ASIR) and annual percentage change (APC) trends for histologically-confirmed GCs, stratified by anatomic location (noncardia vs cardia), age group (20-49 vs 50+ years), sex, race, and ethnicity. Joinpoint regression modeling estimated the statistical significance of trend comparisons.

Results: Of 74,520 individuals with noncardia GC, most (66.2%) were GA, with the next largest categories being non-mucosa-associated lymphoid tissue (non-MALT) lymphomas (6.9%), GIST (6.7%), NET (6.4%), and MALT lymphoma (5.6%). Noncardia GA ASIR was significantly higher than other histologies and demonstrated the greatest differences by race and ethnicity. APCs for GA and MALT, both Helicobacter pylori-associated cancers, declined significantly over time, which was driven primarily by trends among individuals ≥50 years-old. NET and GIST APCs significantly increased irrespective of age group, with the highest APCs observed among non-Hispanic white individuals. Cardia GC was rarer than noncardia GC and comprised primarily by GA (87.9%). Cardia GC incidence fell during the study period, which was primarily driven by decline in cardia GA.

Conclusions: GA was the most common histology. On the basis of our findings, the rise in noncardia GC among certain U.S. populations appears predominantly driven by NET and GIST, not GA. Further studies are needed to clarify underlying etiologies for these findings.

Keywords: Adenocarcinoma; Carcinoid; Ethnic and Racial Minorities; Gastric Neoplasm; Helicobacter pylori.

Figure 1.

(A and B) Noncardia and cardia gastric cancer cases by histology and demographic characteristics, SEER-18 (2000–2018). This figure demonstrates gastric cancer incidence by histology and demographic characteristics.

Figure 2.

(A) Noncardia gastric cancer time trends by histology, SEER-18 (2000–2018). (B) Noncardia gastric cancer time trends for non-adenocarcinoma histologies, SEER-18 (2000–2018). This figure illustrates the ASIRs and modeled ASIRs for noncardia gastric cancer histologies, for combined races, ethnicities, and sexes, among individuals aged 20 years or older. The annual percent change (APC) represents the change in incidence as a percentage of the previous year’s rate in a linear fashion. For GA and MALT and non-MALT lymphomas, ASIRs and APCs decreased significantly over the time period, whereas for NET and GIST, ASIRs and APCs increased significantly over time. (B) Illustrates the same information, but GA is removed to allow re-scaling of the y-axis and better visualization of the time trends for the rarer non-GA histologies.

Figure 3.

(A–E) Modeled noncardia gastric cancer age-standardized incidence rate (ASIR) trends by race and ethnicity for each histology type, ages 20 and older, SEER-18 (2000–2018): (A) adenocarcinoma, (B) non-MALT lymphoma, (C) MALT lymphoma, (D) NETs, and (E) GISTs. This figure illustrates the modeled ASIRs for each histology stratified by race and ethnicity, with each race and ethnicity represented by a different solid-colored line (men and women combined). Asterisk is used to denote groups with statistically significant APC during the time period.

Figure 4.

(A–E) Modeled noncardia gastric cancer age-standardized incidence rate (ASIR) trends by sex for each histology type, ages 20 and older, SEER-18 (2000–2018): (A) adenocarcinoma, (B) non-MALT lymphoma, (C) MALT lymphoma, (D) NETs, and (E) GISTs. This figure illustrates the modeled ASIRs for each histology for men versus women. For all histologies, except for NET, men had significantly higher ASIRs compared with women. The largest differences in ASIR between men and women were observed for GA and MALT lymphoma and NET. The ASIR for NET noticeably diverged for men and women, with women demonstrating a sharper increase, whereas the ASIR noticeably converged for GIST.