No evidence for Spironolactone Causing Cancer — Donovan Hair Clinic
Spironolactone is commonly used as a treatment for androgenetic alopecia in women as well as a treatment for acne and hirsutism. Spironolactone is formally approved by the US Food and Drug Administration (FDA) for the treatment of heart failure, edema and ascites, hypertension, and primary hyperaldosteronism. It is also commonly prescribed as part of genderaffirming care, and it is part of the the Endocrine Society guidelines as a hormone blocking treatment for transgender women (male transitioning to female).
In past articles, I have reviewed individual prior studies showing data that spironolactone does not seem to be associated with breast cancer. (see prior article No Evidence for Breast Cancer with Spironolactone). Spironolactone is even studied nowadays for treating hair loss women who already have breast cancer with no evidence that it increases recurrence rates.
Despite these reassuring studies, one should note that spironolactone carries an official warning from the US Food and Drug Administration regarding potential for tumorigenicity. This warning was placed because of animal studies using very high doses of spironolactone ( ie doses up to 150 times greater than human doses) that showed spironolactone facilitated development of liver, testicular, and breast adenomas.
Bommareddy et al, 2022
Authors set out to determine the pooled occurrence of cancers, in particular breast and prostate cancers, among those who were ever treated with spironolactone. They looked at studies that formally reported the occurrence of cancers in men and women 18 years and older who were exposed to spironolactone.
Seven studies met eligibility criteria with a total population of 4 528 332 individuals (mean age, 62.6-72.0 years; in the studies without stratification by sex, women accounted for 17.2%-54.4%).
The studies included various cancer types including prostate cancer (n = 4 studies), breast cancer (n = 3 studies), ovarian cancer (n = 2 studies), bladder cancer (n = 3 studies), kidney cancer (n = 2 studies ), gastric cancer (n = 2 studies), and esophageal cancer l (n = 2 studies). All studies were considered to be of low risk of bias.
Spironolactone use and Breast Cancer Risk
No statistically significant association was observed between spironolactone use and risk of breast cancer (risk ratio [RR], 1.04; 95% CI, 0.86-1.22; certainty of evidence very low).
Spironolactone Use and Risk of Other Cancers
There was an association between spironolactone use and decreased risk of prostate cancer (RR, 0.79; 95% CI, 0.68-0.90; certainty of evidence very low). There was no statistically significant association between spironolactone use and risk of ovarian cancer (RR, 1.52; 95% CI, 0.84-2.20; certainty of evidence very low), bladder cancer (RR, 0.89; 95% CI, 0.71-1.07; certainty of evidence very low), kidney cancer (RR, 0.96; 95% CI, 0.85-1.07; certainty of evidence low), gastric cancer (RR, 1.02; 95% CI, 0.80-1.24; certainty of evidence low), or esophageal cancer (RR, 1.09; 95% CI, 0.91-1.27; certainty of evidence low).
Conclusion and Summary
This study supports that general notion that spironolactone does not seem have a concerning cancer signal for the main types of cancer. It may in fact, have a decreased risk for prostate cancer. Certainly for breast cancer, the data seems to suggest that cancer is not increased. The authors point out that the certainty of the evidence was low and future studies are needed.
Bommareddy et al. Association of Spironolactone Use With Risk of Cancer: A Systematic Review and Meta-analysis. JAMA Dermatol. 2022 Feb 9;e215866.