Clinicopathological Characteristics and Risk Factors of Young-Onset Gastric Carcinoma: A Systematic Review and Meta-analysis.

INTRODUCTION:The characteristics of gastric carcinoma in young individuals differ from that in older individuals. We conducted a systematic review and meta-analysis to explore the clinicopathological features and risk factors associated with young-onset (younger than 50 years) gastric carcinoma. METHODS:We searched for studies published between January 1, 1990, and September 1, 2023, on patients with young-onset gastric carcinoma in PubMed, EMBASE, Web of Science, and MEDLINE to explore clinicopathological characteristics among this specific patient group. Extracted information included the proportion of patients with symptoms or family history of gastric cancer, tumor location, and histological features such as Lauren or World Health Organization histological classification and degree of differentiation. Additional analyses were conducted on risk factors such as positive family history, Helicobacter pylori infection, or high-risk nutritional or behavioral factors. The estimates were derived using random or fixed-effect models and included subgroup analyses based on different sex and age groups. This study was registered in PROSPERO (CRD42023466131). RESULTS:We identified 5,696 records, 1,292 were included in the quality assessment stage. Finally, 84 studies from 18 countries or regions including 89,447 patients with young-onset gastric carcinoma were included. Young-onset gastric carcinoma has slight female predominance (53.7%, 95% confidence interval [CI]: 51.6-55.7%), with most having symptoms (87.0%, 95% CI: 82.4%-91.7%). Family history was reported in 12.1% (95% CI: 9.5%-14.7%). H. pylori infection was detected in 60.0% of cases (95% CI: 47.1%-72.8%). Most of these carcinomas were in the non-cardia region (89.6%, 95% CI: 82.4%-96.8%), exhibiting Lauren diffuse-type histology (71.1%, 95% CI: 66.8%-75.3%) and poor/undifferentiated features (81.9%, 95% CI%: 79.7-84.2%). A positive family history of gastric cancer was the most important risk factor associated with the development of gastric carcinoma in young individuals (pooled odds ratios 4.0, 95% CI: 2.8-5.2), followed by H. pylori infection (odds ratio 2.3; 95% CI: 1.4-3.2) and dietary and other lifestyle risk factors. DISCUSSION:Young-onset gastric carcinoma exhibits specific clinicopathological characteristics, with positive family history being the most important risk factor. Most of the patients were symptomatic at diagnosis. These findings could help to inform future strategies for the early detection of gastric carcinoma among young individuals.