Incidence patterns of neuroendocrine neoplasms in California.

Abstract

242 Background: Neuroendocrine neoplasms (NENs) are a heterogeneous group of tumors that typically account for < 5% of tumors arising in any organ site. Both the low incidence and heterogeneity contribute to the paucity of epidemiologic data regarding risk factors. However, evidence suggests that incidence rates in the U.S. are rising. We aimed to further characterize the burden of NENs in California. Methods: Using data from the California Cancer Registry (CCR), we identified all newly diagnosed NENs arising from pulmonary (including SCLC) and gastrointestinal (GI) sites from 1992-2015. We estimated age-adjusted incidence rates (AIR) standardized to the 2000 U.S. census population. We calculated annual percent change (APC) in AIRs using Joinpoint regression and compared AIRs by sex, race-ethnicity, primary tumor site, and county of residence categorized as urban, suburban or rural using SEER∗Stat. Results: From 1992-2015, 97,398 NENs were reported, with 40,099 GI (not lung or bronchus). Overall AIR was 12.5 per 100,000 person-years. Most NENs were of pulmonary (AIR 7.6) or colorectal (AIR 1.3) origin. Females had lower AIR with IR ratio (IRR) vs. males (0.80 95% CI 0.79-0.81). However, females had higher rates of gastric (IRR 1.22 95% CI 1.12-1.32) and appendiceal (IRR 1.19 95% CI 1.07-1.33) primaries vs. males. Compared to non-Hispanic (NH) whites, NH blacks had an IRR of 1.06 (95% CI 1.03-1.09), Asian/Pacific Islanders had an IRR of 0.46 (95% CI 0.45-0.48), and Hispanics had an IRR of 0.57 (95% CI 0.56-0.58). For all NEN subtypes, we estimated lower rates for residents of urban counties (IRR 0.83 95% CI 0.80-0.86) and suburban counties (IRR 0.94 95% CI 0.90-0.97) vs. rural counties. However for GI NENs, we estimated higher rates for residents of suburban counties (IRR 1.11 95% CI 1.03-1.18) and urban counties (IRR 1.10 95% CI 1.03-1.18) vs. rural counties. We found that rates of pulmonary NENs decreased since 1992 (APC -2.6), but rates increased in colorectal (APC 3.9) and all other GI primaries (all APCs ≥ 2.8). Conclusions: Based on these results we conclude that incidence rates for GI NENs reported to CCR steadily increased from 1992-2015. Residence in a suburban or urban county was associated with increased incidence of GI NENs. Additional analyses are ongoing.