A nomogram for predicting cancer-specific survival in different age groups for operable gastric cancer: a population-based study

Background: The age thresholds for differentiating young and elderly patients are still under debate. This study aimed to evaluate the cut-off age for differentiating patients along with the prognostic value of age for operable gastric cancer (GC).

Methods: Patients diagnosed with resected gastric adenocarcinoma were identified from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database (training cohort and internal validation cohort) and Liaoning Cancer Hospital (external validation cohort). Kaplan-Meier plots were used to compare cancer-specific survival (CSS) across different age groups. Univariate and multivariate analysis was conducted using a Cox regression model. Predictive ability of the nomogram was determined by the Harrell's concordance index (C-index), calibration curves, and Akaike's Information Criterion (AIC).

Results: A total of 17,339 patients with GC were included. According to the univariate analysis results, CSS was similar among patients aged 20-69 years old, started to worsen for patients over the age of 70, and was the worst for patients older than 79 years in the training cohort. Thus, we further divided the age groups into 20-69, 70-79, and >79, and multivariate analysis showed that patients above 70 years of age had worse CSS. The nomogram was established based on the results of the multivariate analysis. The C-indexes for the training, internal, and external validation cohorts were 0.7531, 0.7344, and 0.7431, respectively.

Conclusions: This study showed that age had a relative predictive ability for CSS, 70 years should be the cut-off age, and age ≥70 years is an independent prognostic risk factor for GC patients who undergo surgery. These data highlight the importance of individualized treatment to improve the prognosis of patients with GC.