Ovarian cysts are fluid-filled sacs that develop in a woman’s ovary. They are very common and usually cause no symptoms, but in some cases can trigger pelvic pain and bloating.Some ovarian cysts turn out to be cancerous tumours and have to be surgically removed.
Opinion is still divided on watchful waiting, with many doctors across the world believing benign cysts should be surgically removed in the majority of cases.
This latest study is the largest to date on the ‘watchful waiting’ approach, which followed nearly 2,000 women as they were scanned in the years after a benign cyst diagnosis.
Out of the 1919 women in the trial, one in five (20 per cent) had cysts that disappeared of their own accord, and 16 per cent underwent surgery. Overall, in 80 per cent of case either the cyst resolved or did not need intervention. The average age of the women in the study was 48, and the average size of the cyst was 4cm.
Only 12 women were subsequently diagnosed with ovarian cancer, making the risk of cancer 0.4 per cent. However, the researchers caution this may be due to the tumours being initially misdiagnosed as non-cancerous on the initial ultrasound scan, rather than a benign cyst turning cancerous.
The rate of other complications, such as ovarian twisting or cyst rupture was 0.4 per cent and 0.2 per cent respectively.
The research team say these risks must be assessed alongside the risks of surgical removal. The risk of complications, such as bowel perforation, for surgical removal of cysts among women aged 50-74 is between 3 and 15 per cent
Professor Dirk Timmerman, lead author from KU Leuven explained: “Despite these surgical risks being small, if the women in this age group underwent surgery in our study then we could speculate that 29 to 123 of them could have suffered severe surgical complications. Instead, only 96 of them underwent surgery, which means severe complications may have been avoided in between 26 to 109 women.”
“Our results may lead to a paradigm shift resulting in less surgery for non-cancerous ovarian cysts – on condition that trained ultrasound examiners reliably exclude cancer”said the lead researcher Professor Tom Bourne, from Imperial College London.