Age-Related Differences in Gastric Adenocarcinoma from 2000-2020: A SEER Database Analysis

Gastric cancer (GC) is the 5th most common malignancy worldwide. Adenocarcinoma accounts for 95% of all GC. While most cases of gastric adenocarcinoma (GAC) arise in older age males, a significant proportion of biological disparity exists between different ages. In this study, we aim to compare the demographics and prognostic outcomes of different ages of patients with GAC.

This retrospective study utilized the GAC cases abstracted from the Surveillance, Epidemiology, and End Results Program's 17 registries dataset from 2000 to 2020. Cases were divided into different age group brackets to comparatively explore characteristics of GAC.

A total of 103,674 cases were identified. The median age was 69 years, with a significant proportion 39.7% (n = 41,154) falling within the 66-80 age bracket cases. Female proportions were higher in the ≤ 35 years age group 47.2% (n = 960) and ≥ 81 years age group 45.7% (n = 9,695). About 45.1% (n = 916) of ≤ 35 years age group cases were Hispanic, while 60% (n = 12,715) of ≥ 81 years age group cases were non-Hispanic White. Ages between 51-65 and 66-80 years had higher proportions of liver metastasis 17% and 16% than their younger and older peers. Age ≤ 35 years cases are more likely to present at cardia 20.5%. Male gender had the worst survival across all age groups, with the worst in the ≤ 35 age group hazard ratio (H.R) 1.22(1.007 - 1.250 p < 0.001). Black had the worst survival across all ages, with the worst in the ≤ 35 years age group H.R 1.405 (1.164 - 1.696 p < 0.001). When plotted against other races in each age group, Hispanics had poor survival at young ages H.R 1.224 (1.069 - 1.401) and superior survival at older ages, with H.R 0.944 (0.902 - 0.987) in the ≥ 81 age group. Tumors located in the greater curvature and overlapping lesions demonstrated worse prognosis compared to cardia. Conversely, tumors in the pylorus and lesser curvature generally exhibited better prognosis.

In the United States GAC predominantly affects older adults, but early-onset cases exhibit aggressive histologies and poor survival, particularly more common in Hispanics. Black individuals face the worst survival outcomes across all age groups. Gender inclination towards males shrinks at the extremes of ages. At different age brackets, the demographics and prognosis changes, necessitating customized interventions.