For tens of thousands of women, a diagnosis of endometriosis means a life of debilitating pain.
Despite it affecting one woman in ten in the UK, from teenagers through to middle age, treatment options remain limited.
There is no cure and the available treatments often have significant side effects, affecting fertility, for example, because they contain hormones.
Now a hormone-free device, which would circumvent many of the side-effects associated with existing options, is being suggested as a new treatment — and the results so far look promising.
For tens of thousands of women, a diagnosis of endometriosis means a life of debilitating pain. Despite it affecting one woman in ten in the UK, from teenagers through to middle age, treatment options remain limited
Endometriosis occurs when cells similar to those found in the lining of the womb occur elsewhere in the body — commonly within the pelvis.
These cells behave like those in the womb, each month building up and then breaking down and bleeding as part of the menstrual cycle.
However, when they build up outside the womb, these cells cause pain and inflammation and can lead to scarring.
Women with endometriosis often have very painful periods as well as pelvic pain at other times of the month, and it can also cause a range of other conditions, including infertility, bowel and bladder problems caused by scarring, as well as fatigue and mental health and relationship difficulties.
The endometrial tissue can be removed surgically but this is only effective in about a quarter of patients, and 50 percent have a recurrence of their symptoms within five years of an operation.
The other main option is hormone medication. As endometriosis tissue grows when exposed to the female hormone estrogen, treatments that block or reduce the production of estrogen from the ovaries are often used, such as the Pill, the Mirena coil, and gonadotrophin-releasing hormone (GnRH) injections (brand name Zoladex).
But these don’t work for everyone and have side effects such as nausea, headaches, and mood changes.
Endometriosis occurs when cells similar to those found in the lining of the womb occur elsewhere in the body — commonly within the pelvis
They are also unsuitable for women who want to start a family and symptoms usually return once the hormonal medication is stopped.
The latest solution, the drug dichloroacetate (DCA), is already used to treat rare metabolic conditions in children and is being investigated as a possible treatment for certain cancers.
DCA works by blocking changes in the metabolic processes of cells (which occur in the mitochondria, the powerhouse of a cell, that controls how they produce energy); the drug effectively restores cell function to normal.
In 2019, researchers from the University of Edinburgh found that cells from the pelvic wall of women with endometriosis have a different metabolism. The cells in the pelvic wall produced higher amounts of lactate — a chemical by-product of metabolism.
The scientists believe lactate may encourage the growth of abnormal endometrial cells (similar to the behavior of cancer cells, which is why the drug is also being investigated as cancer treatment).
When the Edinburgh team tested DCA in mice, after seven days it reduced levels of lactate and the size of endometriosis lesions.
Now the researchers are trialing the drug on 30 women with the most common type of endometriosis, superficial peritoneal disease, which affects the lining of the pelvis and accounts for 80 to 90 percent of cases.
Because the drug does not contain hormones, it should avoid the side effects associated with conventional treatments.
In the trial, each woman has a dose of DCA matched to her weight, twice a day for six weeks, and patients record their pain.