in a large retrospective study, Chapman Wei said in a in a virtual meeting held by the George Washington University department of dermatology in Washington. The virtual meeting included presentations that had been slated for the annual meeting of the American Academy of Dermatology, which was canceled due to the COVID-19 pandemic.
Spironolactone is an aldosterone antagonist and heart failure medication that, because of its peripheral antiandrogen effects, is often used off-label to treat female androgenetic hair loss. Although it has been available for nigh on half a century and has a well-established favorable safety profile, with no indication of carcinogenic effects, little is known about its use in treating alopecia in breast cancer survivors on endocrine therapies, where there has been a theoretic possibility that the drug’s antiandrogen effects could promote breast cancer recurrence.
Not so, said Mr. Wei, from George Washington University.
He presented a retrospective, propensity score–matched, case-control study that used the Humana Insurance database. The initial comparison was between 746 women who went on spironolactone after their breast cancer diagnosis versus 28,400 female breast cancer patients who didn’t take the drug. The primary outcome was recurrent breast cancer within 2 years after diagnosis.
“We chose 2 years because most breast cancer relapses occur within that time,” Mr. Wei explained.
In the initial unadjusted between-group comparison, the breast cancer recurrence rate was 16.5% in the spironolactone group, significantly higher than the 12.8% rate in more than 28,000 controls. However, in a comparison between the spironolactone group and 746 controls extensively propensity score–matched for acne, hypertension, hirsutism, smoking, illicit drug use, heart failure, primary aldosteronism, and other potential confounding variables, there was no significant difference between spironolactone users and controls, with 2-year breast cancer recurrence rates of 16.5% and 15.8%, respectively.
In a multivariate Cox regression analysis, the stand-out finding was that alcohol abuse was independently associated with a 2.3-fold increased risk of breast cancer recurrence.
Mr. Wei noted that these findings confirm those in a recent literature review by investigators at Memorial Sloan Kettering Cancer Center in New York who found no increase in estrogen levels with spironolactone and no heightened risk of female breast cancer while on the drug in three studies totaling 49,298 patients.
“Spironolactone has the potential to be used as a relatively safe systemic treatment option for the management of [endocrine therapy–induced alopecia] in female breast cancer patients and survivors on endocrine therapies who respond poorly to monotherapy with topical minoxidil,” the Sloan Kettering researchers declared ().
Mr. Wei reported having no financial conflicts regarding his unfunded study.