Published November 7, 2018 News and Trends Biomarkers Successfully Predict When Endometriosis Will Respond to Treatment By staff New Haven, CT—The first-line treatment for managing endometriosis-associated pain is progestin-based therapies, such as oral contraceptives. Whether those will offer any relief is unpredictable, however, according to a new study.A report in the Journal of Clinical Endocrinology & Metabolism describes how biomarkers can predict whether women will respond well to the typical therapy to the painful condition. Endometriosis, which can result in infertility in some cases, affects as many as 10% of women during their reproductive years, according to background information in the report.“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,” explained lead author Valerie A. Flores, MD, of the Department of Obstetrics, Gynecology and Reproductive Sciences, at the Yale School of Medicine. “Such an approach to endometriosis management could better predict which medication each individual patient responds to and minimize delays in providing the optimal medical therapy.”Flores and coauthors hypothesized that progesterone receptor (PR) levels in endometriotic lesions could determine response to progestin-based therapy.To test that theory, they conducted a retrospective cohort study at an academic health center, focusing on 52 patients with histologically confirmed endometriosis, and a previous documented response to hormonal therapy.The study team performed immunohistochemistry on sections of endometriotic lesions using a rabbit polyclonal immunoglobulin G for detection of PR-A/B to quantify PR status. How patients responded to progestin-based therapies was determined from review of the electronic medical record.Results indicate that H-score was higher in responders compared to nonresponders. With patients categorized into three groups—high (H-score > 80, n = 7), medium (H-score 6-80, n = 28), and low (H-score ≤5, n = 17) PR status—the threshold of PR greater than 80 was associated with a 100% positive predictive value. The threshold of PR less than 5, meanwhile, was associated with a 94% negative predictive value.“Progesterone receptor status is strongly associated with response to progestin-based therapy. Receptor status in endometriosis could be used to tailor hormonal-based regimens after surgery, and negate trialing progestin-based therapy to determine resistance,” study authors write. “Ascertainment of PR status may allow for a novel, targeted, precision approach to treating endometriosis.”“Examining progesterone receptor status in endometriotic lesions may allow for a novel, targeted approach to treating endometriosis,” Flores added. « Click here to return to Weekly News Update.