Effect of statins on the mortality of long-term survivors of nasopharyngeal carcinoma: a population-based study in endemic area

Background Long-term survivors of nasopharyngeal cancer (NPC) are at risk of excessive mortality. This territory-wide cohort study aims to investigate the relationship between statin use and mortality among 5-year survivors of NPC. Methods This is a retrospective cohort study conducted with data from a territory-wide registry. Patients who survived five years after being diagnosed with non-metastatic NPC in Hong Kong between 1 January 1997 and 30 December 2015 were included. Patients were divided into statin users and statin non-users. We performed the inverse propensity of treatment weighting (IPTW) method to balance confounding factors. The primary outcome of overall survival (OS) was compared between the two groups and stratified by the cause of death, statin types and duration of statin usage. Findings 7872 subjects (2439 statin users and 5433 statin non-users) were included in the final analysis. The 10-year, 15-year, and 20-year survival probabilities of statin users compared to non-users were 89.1 vs. 71.8%, 77.2 vs. 55.1%, and 59.2 vs. 42.4% respectively (HR 0.46, p < 0.001). After adjusting for immortal time bias, the hazard ratio for overall survival was 0.71 ( p < 0.001). Statin use was associated with reduced risk of death due to secondary malignancy (HR 0.51; p = 0.002), cardiovascular disease (HR 0.64; p = 0.002), and pulmonary disease (HR 0.64; p = 0.011). Mortality was significantly lower in long-term statin usage of >6 years (HR 0.31; p < 0.001). In exploratory analyses, patients who received second- or third-generation statins were associated with a lower risk of mortality (HR 0.66 and HR 0.41, respectively), although this finding requires further validation. Interpretation Our study suggests that statin usage is associated with reduced mortality in long-term NPC survivors. Further prospective study is warranted. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.