Effect of statins on the mortality of long-term survivors of nasopharyngeal carcinoma.

Abstract

e18084 Background: Despite the significant increase in five-year overall survival (OS) rate of patients with nasopharyngeal cancer (NPC) over the past few decades, long-term survivors remain at risk of excessive mortality and morbidity. Several population-based studies have suggested an association between statin use and a reduction in cancer morbidity and mortality. This territory-wide cohort study aims to investigate the relationship between statin use and mortality among the five-year survivors of NPC. Methods: This is a retrospective cohort study conducted with data from the Clinical Data Analysis Reporting System (CDARS), a previously validated territory-wide clinical information registry. Patients who survived 5 years after being diagnosed with non-metastatic NPC in Hong Kong between 1 January 1997 and 30 December 2015 were included in the analysis. Patients were divided into two groups: statin users and statin non-users. We performed the inverse propensity of treatment weighting (IPTW) method to balance confounding factors. The primary outcome of OS was compared between the two groups using the Kaplan-Meier method and stratified by the cause of death, statin types and duration of statin usage. Results: 8354 subjects (2598 statin users and 5756 statin non-users) were included in the final analysis. The mean age was 49.3±11.5 years, and 70.8% were male. Baseline characteristics were well balanced after adjustment by IPTW (SMD <0.10). The 10-year, 15-year, and 20-year survival probabilities of statin users compared to non-statin users were 88.4 vs. 70.9%, 76.1 vs. 54.1%, and 58.2 vs. 41.2% respectively (unadjusted HR: 0.49, 95% CI: 0.45-0.54, p<0.001, adjusted HR: 0.43, 95% CI: 0.36-0.52, p<0.001). Statin use was associated with reduced risk of death due to progressive or recurrence disease (HR: 0.74, p=0.039), secondary malignancy (HR: 0.48, p=0.008), cardiovascular disease (HR: 0.58, p=0.003), and pulmonary disease (HR: 0.57, p<0.001). The association of statin use and reduced mortality was duration-dependent. Mortality was significantly lower in long-term statin usage of > 6 years (HR: 0.47; 95% CI: 0.47-0.71, p<0.001) compared to short-term usage (3 months to 2 years). Type 2 statins were associated with a lower mortality compared with type 1 statins (HR: 0.50, 95% CI: 0.37-0.68, p<0.001). Conclusions: Our study suggests that statin usage is associated with reduced mortality in long-term NPC survivors. Further prospective study is warranted.