A group of researchers from the Department of Gynaecology and the Centre for Gender Identity at Rigshospitalet has warned of serious adverse reactions to the drug cyproterone acetate (Androcur®) used for male-to-female transgender hormone therapy and to treat prostate cancer.
In a new study, they have found a link between the drug and the type of brain tumour known as a meningioma. The study also shows that the number of new users in Denmark is rising, primarily due to the demand for transgender hormone treatment. Physician and PhD researcher Anders Mikkelsen is the first author of the study, and he explains:
“Meningioma is a serious adverse reaction, and now several studies have indicated that some of these tumours are due to cyproterone acetate. It’s important that the Danish Medicines Agency assess whether the benefits of the drug continue to outweigh the risks.”
The findings support a French study, which concluded that there is an increased risk of meningioma among users born female. The new study adds that the increased risk is likely to be just as high for people born male.
Lower dosages lower the risk
Meningiomas are tumours in the brain membrane (meninx) and they often require surgical removal. The study showed that nine out of 100,000 people who have not used the drug develop a meningioma each year. Among the people taking part in the study who had been treated with a total dose of less than 10g cyproterone acetate, six developed a meningioma, corresponding to 79 meningiomas per 100,000 individuals per year (a seven-times higher adjusted risk compared with non-users). Among the people taking part in the study who had been treated with more than 10g cyproterone acetate, ten developed a meningioma, corresponding to 188 per 100,000 individuals per year (a 19-times higher adjusted risk compared with non-users).
The results are significant for the treatment offered at Rigshospitalet, explains Malene Hilden, who is a physician and head of the Centre for Gender Identity at Rigshospitalet.
In light of the new knowledge about the area, Rigshospitalet has decided to treat transgenders with a lower dose of the drug than previously, and with good effect. We’re currently looking at whether we should continue this practice or look at other alternatives,” says Malene Hilden.
Number of users tripled
Cyproterone acetate treatment was rare in Denmark. Only 0.035% of the population redeemed a prescription for the drug in the study period, but the number of new users tripled from 2013 to 2019, and the percentage taking the drug for transgender hormone therapy rose from 8% to 65%.
The study has been published in the international Journal of Neurology, Neurosurgery, and Psychiatry. Read the study here: jnnp.bmj.com/content/early/2021/06/28/jnnp-2021-326138. Publication date: 30/6/2021.
Dr. Anders Mikkelsen, PhD stud., tel: +45 61 33 55 45, e-mail: firstname.lastname@example.org
Prof. Øjvind Lidegaard, dr.med., tel: +45 40 63 22 68, e-mail: email@example.com
Malene Hilden, Consultant, Head of the Centre for Gender Identity, tel: +45 28 18 89 85, e-mail: firstname.lastname@example.org