December 4, 2018

Most ovarian cysts may not need surveillance

At a Glance

  • Women with simple ovarian cysts detected by ultrasound did not develop ovarian cancer at elevated rates over the next three years.
  • The results add to the growing evidence that simple ovarian cysts without accompanying symptoms aren’t dangerous.
Woman describing symptoms to a doctor. Simple ovarian cysts are often followed with repeated imaging for years, but the study found that this practice may not be necessary.FatCamera/iStock/Getty Images Plus

Ultrasound imaging of the pelvic area is used to help determine the cause of symptoms such as pelvic pain and abnormal bleeding in women. These scans often also find cysts in the ovaries. Because of concerns about ovarian cancer, these cysts may be followed with repeated imaging over many years. Some women even undergo surgery for these simple cysts to determine whether they contain cancer.

In recent years, research has suggested that simple cysts found this way are most likely not dangerous. To examine the issue in more detail, researchers led by Dr. Rebecca Smith-Bindman at the University of California at San Francisco and Dr. Diana Miglioretti at UC Davis performed a large study in collaboration with Kaiser Permanente Washington. The study, supported by NIH’s National Cancer Institute (NCI), appeared online on November 12, 2018, in JAMA Internal Medicine.

The team collected medical records for more than 72,000 women who had one or more pelvic ultrasound scans between 1997 and 2008. Cases of ovarian cancer during the study period were found by linking the medical records with statewide cancer registries.

The researchers identified 142 women who were diagnosed with ovarian cancer. They compared the scans from these women with scans from more than 900 women without cancer who were matched by age, body mass index, and the year of the ultrasound. A radiologist reviewed the ultrasound scans and recorded the size and characteristics of all ovarian cysts larger than one centimeter. The team then used this information to calculate the risk of ovarian cancer over the three years following the scans.

Most of the cysts observed in the study were simple ovarian. By extrapolating their results to the full group of 72,000 women who underwent ultrasound, the team estimated that about 23% of the 72,000 women younger than 50 and 13% of those over 50 had a simple ovarian cyst. Among those with a simple cyst, however, only a single woman developed ovarian cancer during the study period. She received a CT scan following the ultrasound because of severe, persistent pain.

Among the women who were diagnosed with ovarian cancer, complex cystic masses were the most common finding, followed by solid ovarian masses. The researchers estimated that 9 to 11 out of every 1,000 women younger than 50 with a complex cyst or solid mass would develop ovarian cancer over the next 3 years. This increased to 65 to 430 out of every 1,000 women over the age of 50. In contrast, fewer than 1 out of 1,000 women in both age groups with only a simple ovarian cyst would develop ovarian cancer.

“Our study found that asymptomatic simple ovarian cysts of any size should be considered normal findings in women of any age and ignored,” says Smith-Bindman. “Following these cysts with additional imaging does not lead to the detection of ovarian cancer.”

—by Sharon Reynolds

Related Links

References: Risk of Malignant Ovarian Cancer Based on Ultrasonography Findings in a Large Unselected Population. Smith-Bindman R, Poder L, Johnson E, Miglioretti DL. JAMA Intern Med. 2018 Nov 12. doi: 10.1001/jamainternmed.2018.5113. [Epub ahead of print]. PMID: 30419104.

Funding: NIH’s National Cancer Institute (NCI).