Risk of Breast Cancer in Association with the Use of Second-generation Antipsychotics

Abstract

Objective: Previous studies regarding the relationship between the risk of breast cancer (BC) and antipsychotics use have reported inconsistent findings. Insufficient sample size and/or observation period may have hindered revealing the risk of BC associated with antipsychotics use. We aimed to investigate whether the use of second-generation antipsychotics (SGA) is associated with increased risk of BC. Methods: We used the Health Insurance Review Agency database in South Korea between 2008 and 2018. The index date was determined as the date of the first antipsychotic prescription. We selected women prescribed SGAs for more than 30 days within a year from the index date and age-matched controls, yielding 498,970 cases and 997,940 controls. The Cox proportional hazards regression model was used for estimating the risk. Results: The incidence rates of BC were 109.74 and 101.51 per 100,000 person-years in the case and control groups, respectively. There was an increased risk of BC in the case group (hazard ratio [HR] = 1.08, 95% confidence interval [CI] 1.04−1.13). There was a higher risk of BC in subjects prescribed with ≥ 10,000 mg of olanzapine equivalent dose (HR = 1.29, 95% CI 1.14−1.46) than those with ＜ 10,000 mg (HR = 1.05, 95% CI 1.00−1.11). The increased risk of BC in the case group became significant after six years of the observation period (≥ 6 years: HR = 1.24, 95% CI 1.14−1.35, 3 to ＜ 6 years: HR = 1.06, 95% CI 0.97−1.15, ＜ 3 years: HR = 1.02, 95% CI 0.95−1.09). Conclusion: This study indicated that the use of SGAs is associated with increased risk of BC in a long-term relationship with a dose-response pattern.

Risk of Breast Cancer With Prolactin Elevating Antipsychotic Drugs

“…Mentally ill patients face disparities in screening/prevention of common cancers and are more likely to die from breast cancer, and women with psychotic disorders are about half as likely as the general population to receive mammography screening 35 . Our data and the other publications 36–43 reviewed previously suggest that the use of antipsychotic drugs that elevate prolactin may contribute to incident cases of breast cancer. We also report a surprisingly elevated association of breast cancer risk with category 2 drugs, particularly in younger women, aged 18 to 50 years.…”