According to a 2019 study, a higher percentage of complex ovarian cysts may be cancerous, estimating that among those age 50 or older, 6.5% of individuals with complex ovarian cysts may be diagnosed with ovarian cancer within 3 years. However, most ovarian cysts are benign, meaning that they are noncancerous. The risk of cancer in those with complex ovarian cysts is estimated to be between 0.4% to 6.6% . The UKCTOCS study found that fewer than 1 out of 1,000 women in both age groups with only a simple ovarian cyst would develop ovarian cancer. Therefore, the percentage of complex ovarian cysts that are cancerous is relatively low, but it is still important to monitor them closely and seek medical attention if any concerning symptoms arise.