IT is a condition that affects hundreds of thousands of women in Scotland, but achieving a diagnosis takes more than eight years on average and both access to treatment - and its success rate - is unpredictable.

Now the mysteries and breakthroughs in our understanding of endometriosis will be put in the spotlight as more than 1,100 experts from over 50 countries around the globe descend on Edinburgh for a four-day conference, starting on Wednesday, where nearly 600 original research papers will be shared.

The prestigious World Congress on Endometriosis (WCE) will bring together gynaecologists, surgeons, discovery scientists, data scientists, pain experts, fertility experts, allied health professionals and representatives from patient organisations to share the latest developments on a disease associated with excruciating pain and infertility for sufferers.

The Herald: Professor Andrew HorneProfessor Andrew Horne (Image: Edinburgh University)

"The Congress is acknowledged as the biggest event where clinical and scientific progress in endometriosis is presented – this is where leading edge research is revealed by today’s and tomorrow’s committed clinicians and scientists in this specialised field," said Andrew Horne, a professor of gynaecology and reproductive sciences at Edinburgh University and co-president for this year's Congress.

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Among those speaking will be Arnaud Wattiez, a world-renowned surgeon and pioneer in minimally invasive techniques for gynaecological surgery.

Wattiez, a professor of obstetrics and gynaecology who has worked in Dubai for the past eight years after decades as a surgeon in France, said medicine's approach to endometriosis has shifted over the past 35 years from over-treatment to more targeted procedures which produce better results "with less trauma".

He said: "The problem earlier on was that everybody started doing everything and patients ended up with mutilation from too much surgery.

"Now, we are doing much more patient-centred surgery. We have understood first of all that endometriosis is not a cancer, and so sometimes a woman can live with it.

"The difference between cancer and endometriosis is that with cancer you should be radical - you should do surgery that leaves nothing that is cancerous.

"But with endometriosis you can leave some disease, so we can achieve the same results with less trauma for the patients - we do less, but we get more.

"For example, with a bowel resection in endometriosis: when we started it was done by colorectal surgeons who were taught to do sigmoid and rectum resection for cancer, so they were doing the same [in endometriosis].

"A young lady with a 3cm nodule in the sigmoid was having a 30cm resection of the bowel which leads to bowel dysfunction post-op.

"Now, for a 6cm nodule we do a 6cm resection."

The Herald: Arnaud Wattiez said he is seeing more and more very young women with severe diseaseArnaud Wattiez said he is seeing more and more very young women with severe disease (Image: Twitter)

It is unclear what causes endometriosis, with theories ranging from genetics to an immune system malfunction.

It is characterised by tissue similar to that which lines the uterus wall spreading and growing outside of the womb, on organs including the bowel and bladder, or covering the ovaries and fallopian tubes.

The most recent epidemiological study, from 2005, estimated that the disease affects around 10-12% of women worldwide - with serious complications in around 1% of women - but the true prevalence is believed to be higher once asymptomatic cases are included.

One of the unsolved puzzles of endometriosis is why it causes pain in some women, but not others.

"Many times we do laparoscopy for other reasons and we find endometriosis that is not a problem for the lady," said Wattiez.

Also unclear is the connection between endometriosis and infertility.

"The problem of infertility is a real problem," said Wattiez.

"But in my experience I'm not so sure that endometriosis is really causing infertility. Obviously when you have serious stages - you have distortion of the anatomy and so on - you understand that fertility is affected.

"But when I was in France, 85% of my population with deep endometriosis had no children. In Dubai, 85% of my patients with deep endometriosis have many children. Why?

"Well, because they start to have kids earlier with a lot of social pressure to get pregnant, so even if they have pain during sex they still have sex because the pressure is high.

"In Europe, if you have pain during sex, you don't have sex - very simple. And so the link between infertility and endometriosis is a little bit foggy."

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As for the underlying mechanism behind the disease, Wattiez suspects that it may be an epigenetic disorder where certain lifestyle or environmental triggers are responsible for switching on a gene response in certain women.

In his experience, this appears to be occurring earlier.

"From observation, we see more and more serious cases in younger patients," said Wattiez.

"I have 40 years experience in my career now and I don't remember when I was a young doctors seeing so many young patients with such extensive disease - that's clear.

"When we discuss the theory of why, I think it might be epigenetics. Modern life, levels of pollution. I think pollution plays a role."

The Herald: The conference will be held at the Edinburgh International Conference CentreThe conference will be held at the Edinburgh International Conference Centre (Image: EICC)

In Australia, Helena Frawley is leading research aimed at unravelling the pain conundrum and, potentially, developing alternative remedies where surgery and pharmaceutical interventions have failed.

"We know that for at least a quarter to a third of women who have surgical treatment, their pain is no better," said Frawley, a pelvic health physiotherapist and associate professor at the University of Melbourne's School of Health Sciences.

She added: "Surgical treatment can help with some women's pain, but it doesn't help the pain in all women - therefore something else is driving the pain so we need to look beyond surgical treatment, and the same is true for pharmacological treatment.

"For some women drug treatments don't sufficiently manage their pain, so something else is happening that we need to address."

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For Frawley, the key issue are the pelvic muscles.

Her current research project, grant funded by Australia state and national governments, is exploring the relationship between pelvic floor function and persistent pelvic pain (PPP) in women with endometriosis.

The link may seem obvious - but the reality appears much more complex and opaque.

Frawley said: "It's always been known that women with endometriosis have two primary complaints: pain and infertility.

"If we stick with pain, it's generally concentrated in the pelvic region: pain during intercourse, pain with periods, bladder pain, pain when passing a bowel motion.

"The muscles that support all of those organs are called the pelvic floor muscles, and more recently research is emerging that women with endometriosis do seem to have problems with their pelvic floor.

"The question at the moment is: is that related to their pelvic pain? That is what my current research is investigating.

"It's thought that it probably is, because the pelvic floor muscles and the pelvic organs are all controlled by nerves that overlap with each other.

"What we're looking at is, if you treat any problems that you find in the pelvic floor muscles, does that help the woman in terms of her pain?"

The Herald: Helena Frawley, from Australia, will be presenting the latest research pelvic pain in endometriosis at the conference on FridayHelena Frawley, from Australia, will be presenting the latest research pelvic pain in endometriosis at the conference on Friday (Image: University of Melbourne)

The even bigger question is a chicken-and-egg one: what comes first - does endometriosis cause the pelvic problems, or do pre-existing pelvic issues explain why some endometriosis sufferers are susceptible to pain why others are asymptomatic?

"That's exactly what a lot of the current research is trying to determine," said Frawley.

"We don't know the answer to that, but we do know that the severity of the endometriosis - in terms of the pathology of the disease - does not correlate with the pain.

"So some women have quite advanced endometriosis - stage three or four - but their pain does not correlate with that severity.

"Some have no pain, whereas other women with much earlier stage disease might have much more pain.

"So we know that endometriosis is not, in all women, causing the pain."

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This opens up the possibility that non-invasive approaches might offer relief from symptoms.

"This could include exercises to target the pelvic muscles; massage; acupuncture; mindfulness; stretching; or relaxation techniques.

Frawley said: "We're looking at trying to calm the nervous system down because in women with persistent pain it's often that the nervous system has become amplified so that messages of pain are being ramped up.

"We look at general relaxation - breathing, sleep hygiene, good nutrition."

So does it work?

"That's the $64,000 question," said Frawley, who will present the latest findings at the WCE on Friday.

"Evidence is emerging, is what I would say. This is a very new area of research.

"There's not been a lot of research historically into non-surgical and non-drug treatments for endometriosis.

"It's always been considered a medical problem, a pathology, so treating it with anything other than medical, surgical treatment has never been on the radar."