Despite being rare, endometriosis can appear or come back after menopause.
Doctors should be aware of this, particularly if there are complaints of pelvic pain or heavy bleeding, and they must not underestimate the risk of the disease progressing into cancer, an opinion piece written by several obstetrician-gynecologists says.
Researchers also call attention to a major therapeutic dilemma: Should a doctor prescribe hormonal replacement therapy (HRT) to a woman experiencing menopause symptoms, given that this may raise her risk of having endometriosis come back or degenerate into cancer?
The article, “Endometriosis and the menopause: why the question merits our full attention,” appeared in the journal Hormone Molecular Biology and Clinical Investigation.
“Post-menopausal endometriosis is a rare condition but is a reality,” the authors stated.
As an estrogen-dependent disease, endometriosis primarily affects women of reproductive age, its activity lessening or even regressing at the onset of menopause.
However, there have been several reports of cases that demonstrate the disease may still develop at this time, in the absence of menstrual cycles and in a low-estrogen environment. During menopause, the ovaries’ activity drops drastically, including their capacity to secrete hormones.
The fact that endometriosis can appear in such conditions sheds doubt on Sampson’s theory of retrograde bleeding in explaining the disease origin, and implicates other mechanisms, researchers say.
Doubt persists, however, as to whether endometriosis persists into the post-menopausal period, whether it comes back from a pre-existing disease or if it can develop for the first time after menopause.
In any case, researchers propose several sources of estrogen in postmenopausal women that might serve as risk factors for endometriosis: conditions such as obesity, intake of plant-derived estrogens (phytoestrogens), the use of HRT or tamoxifen, and the production of estrogen by endometriosis lesions themselves.
Tamoxifen, a medication used for breast cancer, acts as an anti-estrogen in the mammary tissue, but as an estrogen-stimulating agent in cholesterol metabolism, bone density, and cell proliferation in the endometrium.
HRT, a common treatment used to relieve menopause symptoms, consists of taking hormone supplements, including estrogen, to restore some of the hormonal levels that decrease during menopause.
Other factors that may play a role include stress, genetic factors, hypothyroidism, or fatty acids (unsaturated omega 3).
Another factor to take into account is that HRT may increase the risk of endometriosis symptoms and disease recurrence after surgery to treat severe symptoms. If there are residues of endometriosis lesions before starting HRT, this risk may increase, particularly if the disease was more severe and surgery was incomplete.
Therefore, before prescribing HRT it is imperative “to weigh the risks and benefits,” researchers say.
The authors also call clinicians’ attention to not forgetting the risk of progression into cancer with or without HRT.
Endometriosis is a benign condition, but about 1% of cases are estimated to develop into cancer, most commonly in the ovary, but also in the bowel and even the lung.
Clinicians should be particularly attentive if a woman reports pelvic pain — dysmenorrhea, dyspareunia or chronic pelvic pain — and heavy bleeding. Diagnosis can be done through patient history, clinical examinations and using ultrasound and magnetic resonance imaging (MRI). However, laparoscopy (keyhole surgery) is the only way to fully confirm a diagnosis of cancer.
The first-line treatment for new-onset symptomatic post-menopausal endometriosis should be surgery because of diagnosis uncertainty and the risk of cancer. Medical therapy can be an alternative if pain comes back after surgery or if surgery is contraindicated, including aromatase inhibitors and levonorgestrel or gestodene, two hormonal contraceptives.