Long-term statin use and risk of cancers: a target trial emulation study.

Background And Objectives: Controversy exists regarding potential cancer risks associated with long-term statin use. This study aimed to use real-world data to investigate the association between cancer incidence and sustained statin use over a 10-year period.

Methods: Using territory-wide public electronic medical records in Hong Kong, we emulated a sequence of nested target trials on patients who met indications for statin initiation in each calendar month from January 2009 to December 2011. Statin initiators and noninitiators were matched in a 1:1 ratio to mimic the randomization of eligible person-trials at baseline. Pooled logistic regression was applied to obtain the hazard ratios for the cancer incidence of statin initiation in intention-to-treat analysis, with the adjustment of baseline confounders and the inverse probability weighting accounting for the postbaseline confounders in per-protocol analysis.

Results: Among 8,560,051 eligible person-trials, 119,715 noninitiators were matched to 119,715 initiators for analysis. Over the 10-year study period, the estimated hazard ratio of overall cancer incidence was 0.96 (0.87, 1.05), and the standardized 10-year risk difference was -0.4% (-1.3%, 0.4%) in the per-protocol analysis. For the cancer subtypes of interest (ie, breast cancer, colorectal cancer, hematological cancer, pancreatic cancer, prostate cancer, urothelial carcinoma, and lung cancer), the 10-year risk differences ranged from -0.3% to 0.2% in the per-protocol analysis. No observable risk change for cancer was found in all patient subgroups with regards to their sex, age (<70/≥70 years), Charlson Comorbidity Index (≤4/>4), and statin indication.

Conclusion: Statin use has no impact on cancer incidence over a 10-year follow-up period, including all cancer subtypes of interest and patient subgroups with regards to sex, age, comorbidities, and statin indications.