Association between long-term use of prolactin-elevating antipsychotics and risk of breast cancer: What are the clinical implications?
Recent epidemiological studies have found a link between long-term use of prolactin-elevating antipsychotics and breast cancer in women with schizophrenia. Professor Nicholas Keks was welcomed to the stage at the RANZCP 2023 Congress in Perth, Australia, to provide an overview of these studies, and discuss the clinical implications of the findings.
At the RANZCP 2023 congress in Perth Australia, Professor Nicholas Keks described these findings as a concerning clinical dilemma, which warranted clear communication and informed consent discussions with women being treated long-term with antipsychotics in practice.
His presentation critically reviewed the recent evidence, to evaluate the robustness of the studies and inform clinical discussions.
The evidence
Since 2018, there have been three large epidemiological studies published which examine the risk of breast cancer in women with schizophrenia treated with prolactin-elevating antipsychotics.1,2,3,4
A 2018 case- control study from the Danish Centre Registry did not find a clinically important association between antipsychotic use and risk of breast cancer for antipsychotics identified as either prolactin-elevating or prolactin-sparing.2
Two subsequent studies, published in 2021 and 2022, did report associations between antipsychotic medication use and breast cancer in women with schizophrenia.3,4
Taipale et al. reported no increased risk of cancer if exposure to prolactin-elevating antipsychotics was less than five years, but longer exposure to prolactin-elevating antipsychotics was associated with increased breast cancer risk (adjusted OR 1.56).3
In 2022, Rahman et al. found that exposure to all antipsychotics was associated with an adjusted hazard ratio of 1.35, compared to no exposure. Prolactin-elevating antipsychotics were associated with highest increased risk (adjusted HR 1.62) and prolactin-sparing antipsychotics were not associated with breast cancer risk (adjusted HR 1.02).4
In discussing these results, Professor Keks highlighted the potential for methodological factors such as categorisation of antipsychotics as “prolactin-elevating” or “prolactin-sparing” to influence comparison results and so advised caution in interpretation.
Professor Keks also noted the likely chance that breast cancer is underdiagnosed in women with schizophrenia, reporting that this population are not only 50% less likely than the general population to have a mammogram screening5, but also that they possess increased risk factors overall for breast cancer, including higher rates of obesity, diabetes, alcohol use and smoking.6
Distinguishing the contribution of antipsychotic medication to the risk of breast cancer is an important consideration for clinicians.
He concluded by saying that while these recent studies have not proven causation between treatment with prolactin-elevating antipsychotics and breast cancer, some of the findings are concerning and warrant collaborative and informed decision-making conversations between clinician and patient.
Clinical implications
Professor Keks provided an overview for the audience of potential clinical implications of these findings.
For women being prescribed or taking long-term antipsychotics, clinicians should discuss the potential increased risk of breast cancer with some antipsychotics, in the context of broader treatment benefits and risks for the individual patient.
Professor Keks recommended the use of prolactin-sparing antipsychotics as first-line long term treatment in these patients, as a mechanism to minimise this risk.
He emphasised that, while the literature may not be definitive, the risks should always be communicated to patients and informed consent gathered before moving ahead with treatment decisions.
Our correspondent’s highlights from the RANZCP 2023 congress are meant as a fair representation of the scientific content presented. The views and opinions expressed on this page do not necessarily reflect those of Lundbeck.
AU-NPSCZ-0022. August 2023.
