Endometriosis: Still unanswered questions

Endrometriosis

An estimated 190 million women in the world are affected by the painful consequences of endometriosis, yet there are many unanswered questions about it, not the least of which are its causes, optimal diagnostic methods and treatment.¹

Endometriosis occurs when tissue similar to the inner lining of the uterus -- the endometrium -- grows on other parts of the body, such as the bladder, intestines, diaphragm and other organs and structures of the female reproductive system.² These areas can develop into cysts, lesions and scar tissue. Because the endometrial tissue responds to hormone changes, it can become inflamed during the menstrual cycle and its negative impact on fertility has been documented.

Positively identifying endometriosis is challenging. It can manifest as a variety of painful symptoms but evade detection on scans and examinations.³ For the estimated 10% to 15% of women with endometriosis, it can take over a decade to get a diagnosis. Part of the lag is because researchers still don’t know exactly how endometriosis occurs. Another reason is that some women can have a huge amount of endometriosis—lots of tissue outside of where it should be—but little pain.⁴ Others may not appear to have much endometriosis but have severe pain and infertility.

Positively identifying endometriosis is challenging. It can manifest as a variety of painful symptoms but evade detection on scans and examinations.

Unanswered Questions

Researchers continue to investigate the causes of endometriosis, including retrograde menstruation, environmental factors and bacteria.

Retrograde menstruation occurs when blood from the period flows backward into the abdomen instead of out the vagina.⁵ Because of this, it’s possible that cells from the endometrium (the lining of the uterus) grow on the abdominal or pelvic organs.

Other research has shown that women are more likely to develop endometriosis if they have elevated levels of cadmium in their system, which can be caused by breathing in cigarette smoke or by industrial processes like smelting and burning fossil fuels or municipal waste.⁶

In a recent study, researchers in Japan documented how Fusobacterium might spur the development of endometriosis.⁷ They found that 64% of patients with endometriosis had Fusobacterium in their uterine lining, versus fewer than 10% of women in the control group. While antibiotics might not be a permanent solution, these findings raise the possibility that other therapies might be.

Treatment

Endometrial surgery may be beneficial for women with chronic or severe pelvic pain, for those whom medication no longer relieves symptoms, or for women having difficulty getting pregnant.⁸However, in the U.S., the first-line treatment for endometriosis has been the same since 1957: the birth control pill.⁹ Doctors believed — and some still believe — that if they can control the reproductive cycle with synthetic hormones, they can also control the disease. But the evidence hasn’t borne that out. In its 2010 bulletin on endometriosis, the American College of Obstetricians and Gynecologists stated there are no data to support use of medical treatment to prevent progression of the disease. Another obvious drawback: Patients with endometriosis who want to get pregnant can’t take the pill.

In August 2022, Myovant Sciences and Pfizer Inc. announced that the U.S. Food and Drug Administration approved MYFEMBREE^® (relugolix) as a one-pill, once-a-day therapy for the management of moderate to severe pain associated with endometriosis in pre-menopausal women, with a treatment duration of up to 24 months.¹⁰

“The good news is that there's more awareness among healthcare providers and women than there was just a few years ago,” said Lisa Halvorson, M.D., chief, Gynecological Health and Disease Branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), in an interview. “However, healthcare providers need to be more careful when taking patients' medical histories, and patients need to feel more comfortable providing open and accurate answers. I'd also like to see ways to prevent rather than just treat the condition, so that women don't suffer. That would be the holy grail.”

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