Disparate and Alarming Impact of Gastrointestinal Cancers in Young Adult Patients

Abstract

The rise in the incidence of gastric cancer (GC) and colorectal cancer (CRC) in young adults (YA) remains unexplained. We aim to identify differences in these malignancies between YA and older patients. We retrospectively analyzed the California Cancer Registry for all GC and CRC cases from 2000 to 2012. Pearson's Chi square analysis and stepwise regression model with backward elimination were used to analyze differences in demographic, clinical, and histopathologic features, and log-rank test to compare survival between young (≤ 40years) and older adults (41-90years) with GC or CRC, separately. We analyzed 19,368 cases of GC and 117,415 cases of CRC. YA accounted for 4.6% of GC (n = 883) and 2.8% of CRC (n = 3273) patients. Compared with older patients, YA were more likely to be Hispanic (P < 0.0001) and have poorly differentiated (P < 0.0001), higher histologic grade (P < 0.0001), and signet ring features (P < 0.0001). Synchronous peritoneal metastases were more common in YA patients (32.1% vs. 14.1% GC, 8.8% vs. 5.4% CRC, P < 0.0001). The 5-year overall survival (OS) of YA with CRC or GC was longer than that of older patients with the same stage of malignancy; except YA with stage I GC, who demonstrated poor OS and disease-specific survival (DSS) (65.1% and 67.9%, respectively) which were significantly worse than those of adults aged 41-49years (70.7% and 76.2%, respectively) and 50-64years (69.1% and 78.1%, respectively). YA with GC or CRC have distinctly worse clinical and histopathologic features compared with older patients and are disproportionately of Hispanic ethnicity. These results contribute to improving understanding of younger versus older GI cancer patients.