Given the risk for serious complications, including cancer, it’s understandable why most women choose to have ovarian cysts surgically removed. However, new research is finding that surgery may not be necessary…and in fact, it may be safer to avoid surgery.

Up to 10% of women in the US have surgery at some point in their lives to diagnose a pelvic mass, such as a cyst or tumor, which about 80% of the time is benign. Ultrasound can detect whether a pelvic mass is a benign cyst or a cancerous tumor. However, cysts with just an area of cancer can elude such detection…and very occasionally a cyst that is currently benign can become cancerous later. Cysts can also lead to a sudden abdominal emergency if the cyst ruptures or gets twisted around its blood supply (called torsion). While the risk for either is small (less than 0.5%), given how serious all these scenarios are, it’s understandable why women may feel that it’s safer to have any cyst found on an ultrasound taken out.

On the other hand, the surgery itself is not without risk. Up to 15% of ovarian cyst surgeries lead to serious complications—including damage to other organs…blood clots that form in the legs and travel to the lungs…and slow wound healing or infection.

With such scary statistics from either option, it can feel as if you’re choosing between the lesser of two evils.

Good news: A new study from KU Leuven, a research university in Belgium, suggests that a program of watchful waiting may be safer than surgery.

The study included 2,000 women (average age 48) at medical clinics in 14 countries who had ovarian cysts that were diagnosed by ultrasound to be low risk and who had no symptoms, such as pain or bloating. Rather than surgery, the women were followed for at least two years. During that time, they had repeat ultrasounds and clinical exams at three and six months and then yearly.


  • About 20% of the cysts resolved on their own (disappeared).
  • About 16% of the women had surgery—for instance, because they developed symptoms, or an ultrasound showed changes.
  • Of the women who had surgery, less than 1% turned out to have ovarian cancer.
  • Of the women whose ovarian cysts continued to be observed, 0.2% of cysts ruptured and 0.4% had a cyst torsion.

Bottom line: The researchers conclude that watchful waiting is a safe option for women with ovarian cysts diagnosed as low-risk by ultrasound—which is what most women have—and that women should be made aware of this option. They recommend the schedule used in the study—additional scans at three and six months and then annually. Insurance policies vary, so you’ll need to check whether yours covers additional ultrasounds.