Response to Letter to the Editor: “Progesterone Receptor Status Predicts Response to Progestin Therapy in Endometriosis”

We thank Vercellini et al. for their letter to the editor. We appreciate their comments and agree that the existing clinical paradigm remains. However, for those women undergoing surgery, our scoring system has utility, given that, unfortunately, surgical intervention often fails to provide permanent relief of pain from endometriosis. The cumulative probability of pain recurrence has been 20% to 50%, and the probability of requiring a further surgical procedure has been 15% to 50% (1–5). Frequently, patients receive progestin-based (including oral contraceptives) therapy after surgery. However, given the high recurrence rates, knowing the progesterone receptor status would allow for consideration of alternative hormonal therapies—GnRH analogs, aromatase inhibitors, or androgens (i.e., danazol). The ability to identify patients who will be less likely to respond to progestin-based regimens would, ideally, avoid pain recurrence and the requirement for multiple surgeries. However, as we discussed in our report, we agree that our scoring system or clinical algorithm requires validation in prospective clinical trials, as well as better measures to differentiate responders from nonresponders or partial responders (6).