Spironolactone does not up risk of breast cancer recurrence

Use of spironolactone does not increase the risk of female breast cancer recurrence and may be considered for the treatment of alopecia in survivors, results of a recent study have shown.

“Spironolactone is used off-label for androgenic alopecia because of its ability to arrest hair loss progression and long-term safety profile,” the authors said. “Because spironolactone has oestrogenic effects, there is a theoretical risk for breast cancer recurrence.”

To determine whether spironolactone correlated with a higher risk of breast cancer recurrence, a retrospective analysis was performed using the Humana Insurance database.

The authors used International Classification of Diseases codes to identify patients with a history of breast cancer, who were stratified by spironolactone prescription, and propensity score analysis to match them 1:1 with controls. Patient characteristics and cancer recurrence rates were compared and analysed between the two cohorts.

Overall, 123 patients (16.5 percent) receiving spironolactone developed breast cancer recurrence compared with 3,649 (12.8 percent) who had recurrence without prescribed spironolactone (p=0.004). After propensity matching, no association was found between spironolactone and increased breast cancer recurrence (adjusted hazard ratio [HR], 0.966, 95 percent confidence interval [CI], 0.807–1.156; p=0.953) in adjusted Cox regression analysis.

The study was limited by its retrospective design, the authors noted.

An earlier study on the association of spironolactone use with risk of incident cancers found no evidence of an increased risk connected to the use of the said medication. However, spironolactone correlated with a significantly lower risk of prostate cancer (HR, 0.69, 95 percent CI, 0.60–0.80; p<0.001). [Br J Clin Pharmacol 2017;83:653-663]