Clinicopathologic and molecular features associated with patient age in gastric cancer.

Aim: To compare characteristics and prognosis of gastric cancer based on age.

Methods: A retrospective study was conducted on clinical and molecular data from patients (n = 1658) with confirmed cases of gastric cancer in Seoul National University Bundang Hospital (Seoul, South Korea) from 2003 to 2010 after exclusion of patients diagnosed with lymphoma, gastrointestinal stromal tumor, and metastatic cancer in the stomach. DNA was isolated from tumor and adjacent normal tissue, and a set of five markers was amplified by polymerase chain reaction to assess microsatellite instability (MSI). MSI was categorized as high, low, or stable if ≥ 2, 1, or 0 markers, respectively, had changed. Immunohistochemistry was performed on tissue sections to detect levels of expression of p53, human epidermal growth factor receptor (HER)-2, and epidermal growth factor receptor. Statistical analysis of clinical and molecular data was performed to assess prognosis based on the stratification of patients by age (≤ 45 and > 45 years).

Results: Among the 1658 gastric cancer patients, the number of patients with an age ≤ 45 years was 202 (12.2%; 38.9 ± 0.4 years) and the number of patients > 45 years was 1456 (87.8%; 64.1 ± 0.3 years). Analyses revealed that females were predominant in the younger group (P < 0.001). Gastric cancers in the younger patients exhibited more aggressive features and were at a more advanced stage than those in older patients. Precancerous lesions, such as atrophic gastritis and intestinal metaplasia, were observed less frequently in the older than in the younger group (P < 0.001). Molecular characteristics, including overexpression of p53 (P < 0.001), overexpression of HER-2 (P = 0.006), and MSI (P = 0.006), were less frequent in gastric cancer of younger patients. Cancer related mortality was higher in younger patients (P = 0.048), but this difference was not significant after adjusting for the stage of cancer.

Conclusion: Gastric cancer is distinguishable between younger and older patients based on both clinicopathologic and molecular features, but stage is the most important predictor of prognosis.