29 Mar The use of atypical antipsychotics and the risk of breast cancer (Q10-04)
Posted at 20:10h in
The use of atypical antipsychotics and the risk of breast cancer (Q10-04)
What is the issue?
- Antipsychotic drugs are typically used in the treatment of a number of psychiatric disorders, including schizophrenia and bipolar disease, but the off-label use of these drugs increased significantly even after regulatory warnings.
- Antipsychotics block the effects of dopamine, and thus hyperprolactinemia is a common side effect. Long-term effects of hyperprolactinemia may include breast cancer.
- Few studies investigated the association between antipsychotics and breast cancer.
What is the aim of the study?
- We rapidly evaluated the use of atypical antipsychotics and the potential association with an increased risk of breast cancer, when compared to typical antipsychotics.
How was the study conducted?
- We conducted an observational study, using a nested case-control design, within the the General Practice Research Database.
- The cohort included female patients prescribed at least one antipsychotic prescription (either typical or atypical), between 1 January 1988 and 31 December 2007, with follow-up until 31 December 2010.
What did the study find?
- Of the 106,362 patients prescribed antipsychotics, there were 1,237 diagnosed with incident breast cancer during the follow up period.
- Users of atypical antipsychotics were not at an increased risk of breast cancer (rate ratio [RR]: 0.81, 95% CI: 0.63, 1.05), compared with those who only used typical antipsychotics.
- Results were consistent after considering specific atypical antipsychotics known to significantly increase prolactin levels such as risperidone (RR: 0.86, 95% CI: 0.60, 1.25).
Furthermore, no dose-response was observed in terms of cumulative duration of use and cumulative dose in olanzapine equivalents.
- The results suggest that antipsychotics, either typical or atypical, are not associated with an increased risk of breast cancer.