Abstract C085: Racial/ethnic disparities in pancreatic cancer incidence rates and temporal trends in California (1988-2015)
Authors: Liu Lihua , Zhang Juanjuan , Deapen Dennis , Stern Mariana , Sipin Andrea , Setiawan Veronica Wendy 
Published: August 2020

Abstract
Background: Pancreatic cancer is a leading cause of cancer death in the United States. Racial/ethnic disparities in pancreatic cancer incidence exist, with African Americans experiencing the highest incidence. Little is known about incidence and temporal trends in other minorities, especially in Asian Americans, heterogeneous populations that are the fastest-growing minority in US. To better understand pancreatic cancer burden, we examined pancreatic cancer incidence patterns and temporal trends among detailed racial/ethnic populations, including Asian-American subgroups.
Methods: We identified a total of 97,665 invasive pancreatic cancer cases (ICD-O-3: C25.0-C25.9) using the California Cancer Registry diagnoses between 1988 and 2015. Cases were grouped into mutually exclusive major racial/ethnic groups of non-Hispanic (NH) white, NH black, Hispanic, NH Asian/Pacific Islander (API), and NH American Indian/Alaska Native (AIAN). Asians were further identified by ethnicity of Chinese, Filipino, Japanese, Korean, Vietnamese, other Southeast Asian, and South Asian. Age-adjusted incidence rates (AAIRs per 100,000) by race/ethnicity and time period were calculated. The average annual percent changes (AAPC) in incidence rates between 1988 and 2015 were estimated using Joinpoint Regression.
Results: The AAIRs of pancreatic cancer varied significantly across the aggregated racial/ethnic groups. The AAIRs ranged from the highest of 16.0 (95% CI: 15.6 to 16.4) in NH blacks to 11.5 (95% CI: 11.5 to 11.6) in NH whites, 10.7 (95% CI: 10.5 to 10.8) in Hispanics, 9.2 (95% CI: 9.0 to 9.4) in NH APIs, and to the lowest of 8.0 (95% CI: 7.2 to 8.9) in NH AIAN. Despite the relatively low rate in the NH APIs, the rates across Asian subgroups varied significantly, with rates as high as NH whites observed in Japanese (AAIR: 11.5; 95% CI: 10.9 to 12.1) and Korean (AAIR: 11.0; 95% CI: 10.3 to 11.7) to the low rate in South Asians (AAIR: 6.6; 95% CI: 5.9 to 7.4). A small but significant decline in pancreatic cancer incidence rates was observed among NH blacks (AAPC: -0.5; 95% CI: -0.8 to -0.2). NH AIANs experienced the most sizable and significant surge in pancreatic cancer incidence (AAPC: 4.5; 95% CI: 2.4 to 6.6), followed by South Asians (AAPC: 2.4; 95% CI: 0.3 to 4.5), Koreans (AAPC: 1.6; 95% CI: 0.5 to 2.7), and NH whites (AAPC: 0.4; 95% CI: 0.2 to 0.6).
Conclusions: Our findings provide the most updated trends in pancreatic cancer incidence across multiple and disaggregated racial/ethnic groups in California. We showed significant heterogeneity of pancreatic cancer incidence in Asian Americans, with high-risk Japanese and Korean populations. These results fill a gap regarding pancreatic cancer burden in Asian Americans and underscore the importance of disaggregating ethnic populations in cancer research.
Citation Format: Lihua Liu, Juanjuan Zhang, Dennis Deapen, Mariana Stern, Andrea Sipin, Veronica Wendy Setiawan. Racial/ethnic disparities in pancreatic cancer incidence rates and temporal trends in California (1988-2015) [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C085.