To the Editor.
—The PEPI trial group1 recently demonstrated that in 94% (34/36) of postmenopausal women who developed endometrial hyperplasia in association with estrogen-only replacement, progestin therapy was effective in reversing the hyperplastic changes, while the remaining patients were refractory to progestin therapy. The next natural question that should be considered is whether there are any factors that can reliably predict response to progestin therapy in patients with endometrial hyperplasia. The importance of predicting response to progestin therapy is obvious, considering that the alternative for many patients is hysterectomy.It is reasonable to conjecture that immunohistochemical or molecular markers exist in hyperplastic endometrial tissues, such as estrogen and progesterone receptors (ER/PRs) and proliferative index, which can be exploited to predict response prior to a trial of progestin therapy. In breast cancers, ER/PR status has been shown to reliably predict response to hormonal therapy, and together with a panel of
Tsang P. Estrogen Replacement Therapy and Endometrial Hyperplasia. JAMA. 1996;275(24):1880. doi:10.1001/jama.1996.03530480022023