No one wants to miss ovarian cancer especially in its early stages when you have a chance of successful treatment.

But should we be regularly monitoring women who have had a simple ovarian cyst detected on ultrasound, as most guidelines recommend to avoid missing this particularly deadly cancer?

That is what US researchers investigated in a nested case controlled study, recently published in JAMA.

The study was based on a cohort of adult women from the Kaiser Permanente Washington health care system who had had a pelvic ultrasound at some stage over a 12-year period starting in 1997, and looked at the association of the ultrasound finding with the risk of being diagnosed with ovarian cancer within three years.

On analysing the data from the 72,000 women who underwent the investigation, the first finding was that ovarian cysts were very common, particularly simple ovarian cysts, occurring in more than 15,000 women. Simple cysts were detected in almost one in four women aged younger than 50, and just over one in 12 women aged 50 and over.

Complex cyst structures were far less common, which is fortunate as the study also confirmed that most of the 212 women who were eventually diagnosed with ovarian cancer had a complex cyst structure on ultrasound.

According to their analysis, the detection of a complex cystic ovarian mass on ultrasound increased the likelihood of cancer eight-fold, and if they were 50 or over and found to have ascites as well, the finding was practically diagnostic with the likelihood of having ovarian cancer being over 70 times greater than normal.