Statin use and patterns of breast cancer recurrence in the Malmoeuro Diet and Cancer Study

Background: Accumulating evidence suggests that statins have a beneficial effect on breast cancer prognosis. Previous studies have reported a positive association between statin use and breast cancer survival; however, the relationship between statin use and patterns of breast cancer recurrence remains unclear. Patients and methods: We identified all Malmoeuro Diet and Cancer Study (MDCS) participants diagnosed with incident invasive breast cancer between 2005 and 2014. The follow-up period began at breast cancer diagnosis and continued until the first invasive breast cancer recurrence event, death, emigration or the end of the follow-up (June 8, 2020). We estimated incidence rates (IRs) of recurrence and fit Cox regression models to compute crude and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CIs) for disease recurrence to compare post-diagnosis statin users with non-users. Results: The final study cohort consisted of 360 eligible patients with a median follow-up of 8.6 years. Overall, there were 71 recurrences in 2932 total person-years. According to statin use, there were 14 recurrences in 595 person-years among statin users, and 57 recurrences in 2337 person-years in nonusers. Statin use was associated with a reduced risk of breast cancer recurrence (HRadj = 0.88 [95% CI: 0.82-0.96]). Regarding the pattern of recurrence, statin use was associated with a reduced risk of distant recurrence (HRadj = 0.86 [95% CI: 0.80-0.94]) but not loco-regional recurrence (HRadj = 0.97 [95% CI: 0.87-1.08]). Conclusion: In the MDCS, statin use was associated with a reduced risk of distant breast cancer recurrence, whereas no association between statin use and loco-regional breast cancer recurrence was found. This site-based difference in disease recurrence may be explained by statin's inhibition of epithelialmesenchymal transition. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study found that statin use was associated with a reduced risk of distant breast cancer recurrence but not loco-regional breast cancer recurrence in the Malmoe Diet and Cancer Study cohort.