Posted by 
Women with endometriosis are more than four times more likely to develop ovarian cancer than women without the condition, a 20-year study has revealed.
The findings will come as alarming news for the one in nine Australian women with the chronic illness, who already face often-debilitating pain, nausea and fertility issues.
Endometriosis causes tissue similar to the uterine lining to grow outside of the uterus, leading to inflammation and internal scarring.
READ MORE: Christie's endometriosis was dismissed for decades, now it's 'terminal'
Medical researchers from the University of Utah examined the medical history of almost half a million women over two decades.
They found that women with an endometriosis diagnosis are at 4.2 times greater risk of developing ovarian cancer in their lifetime.
However, for women with some of the more severe sub-types – ovarian endometriomas (cysts) and deep infiltrating endometriosis – this rose to a 9.7-fold higher risk.
Ovarian cancer is the deadliest gynaecological cancer because it's usually diagnosed too late.
Less than half (45 per cent) of women with ovarian cancer will live beyond five years from the time of diagnosis.
However, if caught early while still at Stage One – before the cancer spreads beyond the ovaries and fallopian tubes – the five-year survival rate rises dramatically to 90 per cent.
It's hoped the findings will prompt more targeted cancer screening and prevention programs for women with endometriosis, particularly those with the most at-risk subtypes.
"Given the rarity of ovarian cancer, the excess risk was relatively small, with 10 to 20 additional cases for 10,000 women," Associate Professor Karen Schliep said.
"Nevertheless, women with endometriosis – notably the more severe subtypes – may be an important population for targeted cancer screening and prevention."
The findings of the University of Utah study were published today in the JAMA Network.
