A new study by researchers at Yale School of Medicine has concluded that progesterone receptor (PR) levels are an important predictor of whether women with endometriosis will respond to first-line treatment for the disease.
Progestin-based therapies such as oral contraceptives serve as first-line treatments for managing endometriosis-associated pain. But response to progestins is unpredictable and varies among women with endometriosis, which has been estimated to affect one in 10 reproductive-aged women, and 50% to 60% of women and adolescents with pelvic pain and/or unexplained infertility.
That explains why endometriosis management has been anchored until now on hormonal therapy and surgery. Yet recurrence rates remain high. Gauging patient's response to progestin-based therapy could reduce the risk of disease recurrence by helping determine the best treatment options, the researchers reason.
In a retrospective cohort study, the Yale Medicine researchers studied 52 subjects with histologically confirmed endometriosis, as well as a previous documented response to hormonal therapy. Immunohistochemistry was performed on sections of endometriotic lesions using a rabbit polyclonal Immunoglobulin G (IgG) for detection of PR-A/B.
From electronic medical records, the researchers determined response to progestin-based therapies. PR status was quantified based on patients’ histo (H)-score, which was higher in responders compared to non-responders.
Of the 52 participants, more than half (28) showed high H-scores of > 80, while 17 showed low H-scores of ≤5m and the remaining seven showed medium H-scores of between 6 and 80.
“Receptor status in endometriosis could be used in a similar way to how estrogen receptor and progesterone receptor status is used in breast cancer for personalizing treatment options,” Valerie A. Flores, M.D., of Yale School of Medicine, one of the study’s two corresponding authors, said in a statement. “Such an approach to endometriosis management could better determine which medication each individual patient responds to and minimize delays in providing the optimal medical therapy.”
The study, Progesterone Receptor Status Predicts Response to Progestin Therapy in Endometriosis was published Tuesday in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism.
“Examining progesterone receptor status in endometriotic lesions may allow for a novel, targeted approach to treating endometriosis,” Dr. Flores said.
Joining Dr. Flores as corresponding author was Arne Vanhie, M.D. They co-authored the study along with Hugh S. Taylor, M.D., and Tran Dang.