Age disparities in the trend of colorectal cancer incidence in California.

Abstract

e12528 Background: Colorectal cancer (CRC) incidence has decreased over the past three decades, due in part to screening for pre-malignant polyps. Relatively little is known about CRC incidence among adults under age 50 (when screening recommendations commence for average-risk individuals). We examined CRC incidence trends with a focus on adults under age 50, in order to identify high-risk subgroups. Methods: 231,544 incident CRC cases (including 21,220 adults <50) from the California Cancer Registry from 1988-2009 were analyzed. We assessed age-specific incidence rates by race/ethnic group, gender, and tumor location within the colorectum, and calculated annual percent change (APC) to monitor change in incidence over the 21-year study period. Results: We observed increased CRC incidence rates in the adult population under age 50 in all examined race/ethnic groups, especially in Hispanic males (APC=+7.5%/p=0.0001) and Caucasian females (APC=+6.5%/p<0.0001). Young individuals were also more likely to present with metastatic disease at diagnosis. Overall, African Americans had the highest overall incidence rates and were most likely to present with metastatic disease compared to other groups. Conclusions: Incidence of CRC in adults under 50 is increasing across all race/ethnic groups. The high frequency of metastatic disease at initial presentation in this age group is particularly concerning. However, a considerable limitation of this analysis is the lack of data on family history of CRC. Our observations highlight the importance of identifying at-risk adults under age 50, especially those in higher-risk race/ethnic groups, with the overarching goal of decreasing the burden of CRC through screening and early detection.