Simple ovarian cysts are extremely common in women and do not require additional ultrasound surveillance or surgical removal, according to a new study of more than 72,000 women and close to 119,00 pelvic ultrasound exams over a dozen years.
The study, a collaboration between UC San Francisco and Kaiser Permanente Washington, found that simple cysts are normal, extremely common in both pre- and postmenopausal women, and aren’t linked to a higher risk of ovarian cancer. As a result, unless they are symptomatic, simple cysts can be safely ignored, the researchers found.
By contrast, complex cysts or solid ovarian masses are far less common, but are associated with a significantly higher risk of developing malignant cancer, the authors report. These masses need to be followed or surgically removed.
The paper, published Nov. 12, 2018 in JAMA Internal Medicine, suggests a change in the way that simple cysts are typically monitored and sometimes treated.
“There’s a great deal of unnecessary medical surveillance that goes on for simple cysts,” said corresponding author Rebecca Smith-Bindman, MD, a UCSF professor in the Department of Radiology and Biomedical Imaging. She is also a professor in the departments of Epidemiology and Biostatistics, and of Obstetrics, Gynecology and Reproductive Medicine, and a member of the Philip R. Lee Institute for Health Policy Studies.
“Simple cysts are almost universally benign, but because of concern that they could harbor a cancer precursor, they have resulted in frequent surveillance and referrals to gynecologists and oncologists,” she said. “Our study found that asymptomatic simple cysts of any size should be considered normal findings in women of any age and ignored.”
Ovarian cancer is the fifth leading cause of cancer deaths among women in the U.S., with 22,000 new cases diagnosed and 14,000 deaths, annually.
In the last two decades, increased use of transvaginal pelvic ultrasound has led to frequent identification of ovarian masses. While most of those masses are benign, researchers and professional guidelines have nonetheless recommended ongoing surveillance of simple cysts, due to the poor prognosis of malignant ovarian cancer, as well as concern over a small risk of cancer in masses that appear benign.
This is the first study to quantify the risk of ovarian cancer in a large, unselected population, based on the ultrasound characteristics of ovarian masses, including simple cysts. The authors sought to identify features that would predict with high certainty whether an ovarian mass was benign and would not require surveillance.
The study tracked 72,093 women who underwent pelvic ultrasound through Kaiser Permanente Washington between January 1997 and December 2008. Approximately 75 percent were less than 50 years old.