Aromatase Inhibitor for Severe Endometriosis

Abstract & Commentary

Synopsis: Successful treatment of severe endometriosis in 2 premenopausal patients is reported.

Source: Shippen ER, West WJ. Fertil Steril. 2004;81: 1395-1398.

Two premenopausal patients with resis tant endometriosis were successfully treated with a combination of the aromatase inhibitor anastrozole, Prometrium, calcitrol, and rofecoxib. Both patients had been diagnosed with endometriosis via laparoscopy, and had undergone GnRH suppression. Although both desired to get pregnant in the future, the pain was bad enough for both patients to request hysterectomy for pain relief. Both had rejected danazol due to its side effect profile as well as the potential temporary nature of its benefits. This regimen achieved rapid success over 3 months, with relief over 24 months after therapy. Confirmatory laparoscopy at 15 revealed no endometriosis. Pregnancy was achieved in both cases after 24 months.

Comment by Frank W. Ling, MD

Although just a case report, I believe that this article has an important message for all of us clinicians. There is potentially incredibly good news here, but also possibly some disturbing news. First the good news: another effective option for the treatment of endometriosis may well be available. Aromatase inhibitors have been approved by the FDA for the treatment of breast cancer, but that is all. Of course, when did the lack of FDA approval prevent insightful clinicians from seeking innovative applications of new drugs? We need to look no further than another aromatase inhibitor, letrozole, to see that its use to enhance folliculogenesis can be effective. As always, the patient must be fully informed as to potential risks as well as the potential benefits of any off-label use of medication. Interestingly, in these 2 cases, the patients chose to try the aromatase inhibitor over approved an approved medication, danazol.

That leads me to the potentially bad news. As we continue to focus on endometriosis for our patients, we sometimes lose sight of the forest for the trees. When we suspect endometriosis (or even when we have proven endometriosis), we must make sure that we have not only ruled out other etiologies for the symptoms. In the case of endometriosis, of course, pain is the primary concern of most patients and their physicians. I have seen many patients, as young as 15 years old, who have been subjected to multiple surgical interventions for pain thought to be related to endometriosis, when, in fact, it was due to another cause. In the case of the 2 patients in this case report, we are not told whether other etiologies were aggressively ruled out. As good consumers of the medical literature, we should remain aware of such issues. So we can easily get tunnel vision, focusing too much on endometriosis, even with new modalities available such as aromatase inhibitors. By the same token, our informed consent must reflect reality, ie, what are the side effects of proven medications such as danazol? Why are patients willing to take anastrozole, but not danazol? Why not other progestins? Is it possible that these patients might have gotten better on the Prometrium alone? I am not a cynic and have been in the same dilemma that these clinicians found themselves in. We have to address unusual circumstances, ie, desperate times require desperate measures. Patients have idiosyncratic biases, preconceptions, fears, etc. We need to address each. We also need to guide and provide the best information for her and her particular situation.

What do you do with this information? Is this case report useful in your practice? Maybe, maybe not. Another weapon in our war against endometriosis is a good thing. We need to use it wisely and only when it is really needed.

Frank W. Ling, MD, Women’s Health Specialists, PLLC, Memphis, Tennessee, is Associate Editor for OB/GYN Clinical Alert.