To the Editor We read with interest the recent publication from the Women’s Health Initiative and the associated Editorial by Joshi et al.1 This Letter concerns the Editorial, which contributes to inadequate information on progesterone.
It is surprising to read under the aegis of JAMA Oncology such misleading pharmacological data. The title and content of the Editorial refers to “progesterone.” Progesterone, the ovarian-produced hormone, has different properties from synthetic progestogens. It is rapidly metabolized and has antiandrogenic and antimineralocorticoid properties. The progestogen used in the Women’s Health Initiative was medroxyprogesterone acetate and not progesterone. Medroxyprogesterone is a more potent glucocorticoid agonist and an androgen in addition to its progestogen potency. There are numerous publications, including ours,2 showing that progesterone and medroxyprogesterone display different pharmacological and clinical properties and effects.3 It is time for the scientific community to respect the pharmacology and to increase their knowledge on steroid potencies. Indeed, observational and case-control studies conducted in France, where the use of progesterone is widespread in menopause treatment, reported a lower risk of breast cancer with progesterone therapy than with synthetic progestogens.4,5
Gompel A, Plu-Bureau G. Progesterone and Synthetic Progestin Controversies. JAMA Oncol. 2015;1(7):987. doi:10.1001/jamaoncol.2015.2283