One size doesn’t fit all, when using hormone therapy to treat endometriosis

Endometriosis — a condition caused by uterine tissue growing outside of the organ — affects 10% of reproductive-aged women, whom it causes chronic pain that is significant and debilitating. The standard first-line treatment for all women with endometriosis is hormonal, specifically progestin-based, therapy.

Yet a team of researchers at Yale has shown that the effectiveness of progestin-therapy depends on whether a woman’s endometriotic lesions have the progesterone receptor (PR) present. This study appears online in the Journal of Clinical Endocrinology Metabolism.

The researchers tested the endometriotic lesions of 52 women who had undergone surgical evaluation for endometriosis at Yale New Haven Hospital for their PR status. They found a significant association between PR status and responsiveness to progestin-therapy. Those whose endometriotic lesions were PR-positive responded much better to the progestin-therapy, while those whose lesions were PR-negative found little relief from progestin-therapy alone.

From these findings, the research team concluded that knowing a woman’s PR-status may help them develop a “novel, targeted, precision-based” approach to treating and managing endometriosis individually. “Receptor status in endometriosis could be used in a manner analogous to the use of estrogen/progesterone receptor status in breast cancer for tailoring hormonal-based regimens,” said Dr. Valerie Flores, first author and clinical instructor at the Yale School of Medicine.

“Such an approach to endometriosis management would make trialing progestin-based therapy to determine response unnecessary,” said Flores, “and would therefore minimize delays in providing the optimal medical therapy for each individual patient.”

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This study was funded by a grant from the National Institutes of Health. Other authors on this study include Arne Vanhie, Tran Dang, and Hugh Taylor.