A UK study has signified that high doses of a commonly used hormonal treatment – cyproterone acetate – may elevate the risk of benign brain tumours.
Led by a team at the University of Bristol, the novel findings suggest that the drug cyproterone acetate (CPA) – a hormonal treatment employed widely to combat conditions such as excessive hair growth, early puberty, and prostate cancer may be associated with an increased risk of meningioma, the most common type of benign brain tumour.
The research is published in Scientific Reports and includes over eight million patients.
Dangers of meningiomas
Meningiomas are slow-growing, benign tumours that are often identified incidentally through imaging. They can cause severe disability through compressing or squeezing the adjacent brain, nerves and vessels and pressure effects within a fixed cranial vault. Prior investigations have identified an association between the use of hormonal treatments and the growth of meningiomas – most notably prolonged and high doses of cyproterone acetate.
How cyproterone acetate impacts tumour growth
High doses of cyproterone acetate – 50mg per day – are administered to male patients who have inoperable prostate cancer, which can result in excessive hair growth (hirsutism), or those who are undergoing hormonal therapy for male-to-female transitions. Moreover, lower doses of CPA, between 2-10mg per day, are commonly employed in combination with oestradiol to treat androgen-associated alopecia or female seborrhoea.
To comprehensively understand the effects of the widely-used drug, the team, comprised of researchers from the University of Bristol, the National University of Singapore, and the University of Cambridge, performed a systematic review and meta-analysis of four studies. The investigation included 8,132,348 patients, providing a comprehensive view of the association between cyproterone acetate and meningiomas.
165,988 of the study’s participants were identified as taking cyproterone acetate in a range of doses. Next, the researchers examined the occurrence of meningioma in patients using high versus low cyproterone acetate, discovering that there is a significant association between high dose usage and increased meningioma risk. Furthermore, this association was not demonstrated in low doses.
Keng Siang Lee, a medical student and the study’s lead author from Bristol Medical School at the University of Bristol, said: “The cause of meningiomas is controversial, but there is strong evidence to suggest a plausible role for sex hormones in the onset of meningioma. We know it has a predilection for females, especially after puberty. Furthermore, fluctuations in meningioma growth during the menstrual cycle, pregnancy, and breastfeeding have also been well-documented. We are also aware of the well-characterised distribution of progesterone, oestrogen, and androgen receptors in certain meningiomas located at the base of the skull.
“In light of these results, prescription of high dose cyproterone acetate, especially for off label indications, should be considered carefully. Additionally, we suggest that routine screening and meningioma surveillance by brain MRI offered to patients prescribed with cyproterone acetate is likely a reasonable clinical consideration if given at high doses for long periods of time.
“However, our study underscores the currently limited evidence about the risk of intracranial meningioma associated with low dose cyproterone acetate. It is still unknown whether or not cyproterone acetate below a certain threshold may be completely safe in terms of the risk of meningioma. The results obtained herein suggest the necessity for further clinical research on intracranial meningioma associated with cyproterone acetate.”
