Racial disparity of stage III rectal cancer among young adults: A combined NCDB/SEER analysis.

Abstract

85 Background: With the advent of screening colonoscopy in 1997, there has been an overall decreasing incidence in rectal cancer. Recently, the ACS updated guidelines to started screening patients at 45 years old. The purpose of this study was to further investigate incidence and overall survival trends for rectal cancer among young white and African-American (AA) patients using the SEER and NCDB databases. Methods: Rectal cancer incidence trends in SEER-9/SEER-18 were analyzed for patients < 50 years old. Treatment and survival outcomes were also evaluated using the NCDB (2004-2014). White and AA patients were matched using propensity score analysis and inverse probability of treatment weighting (IPTW). Baseline characteristics were compared with Pearson Chi Square, before and after matching. Univariate and multivariable analyses were performed with Kaplan-Meier and Cox proportional hazard modeling, incorporating the IPTW-adjusted population. Results: 6,144 (SEER) and 17,819 (NCDB) young, white or AA patients were identified. There was an overall increase in incidence of stage III (APC 5.57, P < 0.05) and IV (APC 4.66, P < 0.05) rectal cancer among young white patients. For the entire population, there was improved overall survival for white patients compared to AA patients, even after adjusting for confounding factors. Subset analysis of both the SEER and NCDB databases revealed that the largest disparity was between AAn and white rectal cancer patients, is among the Stage III subset with HR of 1.6 (P < 0.001) and HR of 1.4 (P < 0.001), respectively. Conclusions: There is an alarming increase in younger patients being diagnosed with rectal cancer. Specifically, there appears to be more locally advanced rectal cancer among younger patients and a racial disparity favoring whites for survival outcomes was identified. This research further supports the utility of earlier screening and to identify the factors involved in this rise in rectal cancer incidence.