Cancer Incidence and Prevalence in Relation to Proximity to a Nuclear Power Plant in Gyeongju, Republic of Korea

Background: Previous studies on cancer risk near nuclear power plants (NPP) have reported inconsistent results. This study aimed to estimate the standardized incidence ratios (SIR) and standardized prevalence ratios (SPR) of cancer near a NPP in Korea. Methods: Claims data from the National Health Insurance Service (2006–2020) were used to calculate the SIRs and SPRs for all cancers and 17 radiation-related cancer types. Proximity to the Wolsong NPP in Gyeongju, Korea, was categorized into <5 km (region I), 5 to 9.9 km (region II), 10 to 20 km (region III), and 60 to 100 km (region IV). Results: The SIRs for all cancers were 1.12 (95% confidence interval, 0.83–1.41), 1.50 (1.16–1.85), 0.87 (0.76–0.97), and 1.04 (0.91–1.16) in regions I, II, III, and IV, respectively. The SPRs for all cancers were 0.67 (0.59–0.75), 0.78 (0.70–0.87), 0.68 (0.65–0.71), and 0.76 (0.72–0.80) in regions I, II, III, and IV, respectively. In the analyses combining regions I and II, the SIRs for all cancers and stomach cancer, as well as the SPRs for esophageal cancer and lung cancer, were increased in regions located within 10 km from the NPP. Conclusions: Elevated, but statistically nonsignificant, point estimates of the SIR and SPR, with wide confidence intervals, were observed for several outcomes within 5 km of the NPP. Impact: This exploratory study provides information to design further longitudinal studies with individual-level data and more accurate exposure assessment to understand cancer risks near NPPs.