Association between long-term use of prolactin-elevating antipsychotics in women and the risk of breast cancer: What are the clinical implications?

Background Some antipsychotic drugs elevate prolactin, and hyperprolactinaemia is associated with an increased risk of breast cancer. Women with schizophrenia have an increased incidence of breast cancer, but also multiple risk factors for the condition. Method This paper will critically review recent epidemiological studies concerning antipsychotics and breast cancer from a psychiatric perspective. Results Two recent epidemiological studies have found an association between use of prolactin-elevating antipsychotics and breast cancer in women with schizophrenia and other psychotic disorders. Prolactin-elevating drugs include paliperidone, risperidone, amisulpride and haloperidol, whilst prolactin-sparing antipsychotics included aripiprazole, brexpiprazole, cariprazine and quetiapine. In the two studies, estimated increased risks of breast cancer were disconcertingly high (up to 62%), but a third recent study found only a weak dose-response association. There are extensive methodological complications in this research, including the extent to which studies measure other risk factors for breast cancer and disagreement about the extent of prolactin elevation by some antipsychotics. Conclusion Although causation between prolactin elevating antipsychotics and breast cancer in women has not been demonstrated, recent epidemiological reports are worrying. For women on antipsychotics, informed consent should ideally include discussion of breast cancer concerns within the wider context of treatment benefits and risks.