Ovarian Cancer Screening: Assessing the Risks and Benefits

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A 3-question online survey was distributed to US gynecologists to analyze their behaviors toward ovarian cancer screening in accordance with current recommended evidence.
A 3-question online survey was distributed to US gynecologists to analyze their behaviors toward ovarian cancer screening in accordance with current recommended evidence.

Results from an online survey assessing ovarian cancer screening behaviors indicate that gynecologists may be more likely to change their opinions on screening practices when presented with more detailed evidence about benefits and harms of screening, according to a study published in Scientific Reports.

Researchers deployed an online survey to US gynecologists (n=401) to assess ovarian cancer screening practices.  The survey asked 3 questions: 1) Do outpatient gynecologists currently recommend ovarian cancer screening?; 2) Do gynecologists report estimates and beliefs regarding the benefits and harms of ovarian cancer screening by cancer antigen 125 and transvaginal ultrasound testing?; and 3) When provided with an information box that summarizes the findings from the US Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, do gynecologists revise their initial beliefs on ovarian cancer screening?

The primary outcome was the proportion of gynecologists who recommended screening and the proportion of estimates and beliefs regarding the benefits and harms of screening approximating the current best evidence. Secondary measures included the proportion of beliefs approximating current best evidence in relation to clinician recommendation behavior and in relation to the evidence presented in the fact box.

Of the 401 gynecologists surveyed, 231 (57.6%) reported regularly recommending ovarian cancer screening to asymptomatic women of average risk. A total of 40.4% agreed with the current best evidence that there is no reduction in absolute disease-specific mortality as a result of screening. More than half (53.9%) believed that screening reduces ovarian cancer mortality (mean estimate, 21 per 1000 screened).

More than half (55.4%) of those surveyed believed that ovarian cancer screening has harms, including overdiagnosis and unnecessary surgical procedures. When asked the approximate number of false-positive diagnoses among positive diagnoses (96 false-positive/101 positive per 1000 women), 21.5% provided estimates that corresponded with evidence. When asked what percentage of women receiving a false-positive diagnosis would undergo surgery for ovary removal (32 per 1000 women), 3.2% of gynecologists provided correct estimates. More than half (55.9%) of surveyed gynecologists believed that the potential benefit of ovarian cancer screening does not outweigh the potential harms.

Compared with clinicians who recommended screening, gynecologists who did not recommend screening (n=170) were nearly twice as likely to provide an estimate of benefit that corresponds to current evidence (28.6% vs 56.5%). They also more commonly believed that the screening has harms (41.6% vs 74.1%) and were more than twice as likely to believe the potential harms of ovarian cancer screening outweigh its potential benefits (37.2% vs 81.2%).

After the surveyed gynecologists were presented with the fact box summarizing the evidence from the PLCO trial, 194 (48.4%) stated that the evidence did not change their beliefs about ovarian cancer screening. Of the 51.6% who responded that the evidence changed their initial estimates, the mean estimate for cancer-specific mortality reduction decreased from 14.2 to 0.4 per 1000 women, and the mean estimated percentage of false-positive results among all positive test results increased from 43.2% to 65.9%. The number of clinicians who believed that screening has potential harms increased from 43.5% to 87.0%, and those who believed the potential benefit outweighed the potential harms decreased from 59.6% to 30.0%.

“…our findings suggest that the currently used procedure of ovarian cancer screening may tend to stay in place because a considerable number of gynecologists overestimate the screening's benefit and underestimate its harms,” the authors concluded. “Our findings may encourage both editors of medical journals to incorporate fact box summaries in clinical research articles and medical educators to implement trainings on how to correctly interpret medical evidence in general and screening statistics in particular in their medical curricula.”

Reference

Wegwarth O, Gigerenzer G. US gynecologists' estimates and beliefs regarding ovarian cancer screening's effectiveness 5 years after release of the PLCO evidence. Sci Rep. 2018;8:17181.

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