Racial and ethnic disparities in risk of second primary lung cancer among initial lung cancer survivors in the United States.

8037 Background: Previous studies have reported significant racial/ethnic disparities in incidence and mortality of lung cancer. However, with several studies reporting significantly increased risk of second primary lung cancer (SPLC) among these first primary lung cancer (FPLC) survivors, we sought to examine SPLC risk among FPLC survivors by race/ethnicity and age utilizing a large population-based database. Methods: From 17 United States population-based Surveillance, Epidemiology and End Results (SEER) program cancer registry areas, we identified 305,432≥12-month FPLC survivors diagnosed between 2000-2021. Standardized incidence ratios (SIRs) and accompanying 95% confidence intervals (CIs) quantified SPLC risk by race/ethnicity (non-Hispanic White, Black, Asian/Pacific Islander [API] and Hispanic), compared with the general population. Excess SPLC risks were calculated based on SIRs and excess absolute risks (EARs) per 10,000 person-years at risk (PYR). Results: Overall, we observed 13,005 SPLCs representing a 5.6-fold significantly increased risk (95% Confidence Interval [CI]=5.51-5.71) among FPLC survivors compared to the general population and an excess of 118 cases per 10,000 PYR. SPLC risk varied significantly by race/ethnicity with Hispanic FPLC survivors presenting highest risk (SIR Hispanic =8.42; CI=7.73-9.16) followed by the API and Black patients (SIR API =6.58; CI=6.11-7.07; SIR Black =5.63; CI=5.32-5.96) (P heterogeneity <0.001). Although 81% SPLC cases were reported among White FPLC survivors, the SIR compared to the other patients was relatively lower among the White (SIR White =5.45; CI=5.35-5.56). Analysis by age at FPLC diagnosis reported a significantly increasing trend in SPLC risk with decreasing age (P trend <0.001). Heterogeneity by race/ethnicity in SIRs was most pronounced in younger, particularly the adolescent and young adult (AYA) patients aged between 20 to 39 years at FPLC diagnosis. Strikingly elevated risk was observed among the Hispanic and API AYA FPLC survivors (SIRs of 49.62 and 87.17, respectively), followed by the corresponding Black and White patients (SIRs of 39.64 and 22.15, respectively) (P heterogeneity <0.001). Similar pattern in racial/ethnic and age-related disparity was observed by latency, with higher SPLC risk among the young and minority patients within first 5 years since FPLC diagnosis. Conclusions: We observed substantial disparities in SPLC risk by race/ethnicity, with patients belonging to minority groups, particularly the Hispanic, and the AYA age group experiencing higher risks. Further research to understand drivers of these observed racial/ethnic and age-related heterogeneity is warranted. Similarly, tailored surveillance strategies are required to reduce disparities among FPLC survivors by accounting for these patient characteristics.