Physicians Would Order Screening Inappropriately for Ovarian Cancer

Today’s Managing Health Care Costs Indicator is 28%

Likelihood a Physician Would Order Ovarian Cancer Screening Tests
 Nonadherent to Evidence-Based Medicine

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We’re often overly enthusiastic about screening efforts – because it makes such good intuitive sense that finding a cancer early would be better (and maybe even less expensive) than finding it late.    But screening for especially rare diseases produces many false positives, and screening for diseases where the treatment is of uncertain efficacy leads to many people living longer with a disease only because it was found sooner.  Screening can sometimes increase medical utilization and cost without helping us gain quality adjusted life years. 

The February 7 Annals of Internal Medicine illustrates how difficult it is for physicians to practice evidence based care.  Over a quarter of physicians reported that they would order ovarian cancer screening on low risk women; while almost 2/3 of physicians (65.4%) reported that they would order ovarian cancer screening for women at medium risk of ovarian cancer.  Both the American College of Obstetrics and Gynecology and the US Preventive Health Services  Task Force have recommended against such testing.

Researchers asked a nationally representative sample of  physicians to review one of three clinical scenarios of women of varying ages who were at low, medium, and high risk of ovarian cancer.  The physicians were then asked how likely it would be that they would order CA125 (a blood test) or transvaginal ultrasounds to screen for ovarian cancer.   One in three surveyed physicians believed incorrectly that there was evidence to support using these screening tests in low or medium risk women.  

Factors that made physicians more likely to order this test
-        The patient asked for a screening test
-        The physician believed incorrectly that evidence supported this screening test in this type of situation
-        The physician overestimated patient risk
-        The physician was older
-        The physician was an obstetrician-gynecologist (I might have expected specialists in this field to perform better, not worse)
-        Physician did no clinical teaching
-        Physician had had cancer him or herself

Patients hate uncertainty – and often believe that a noninvasive test couldn’t hurt them.  We doctors should know better, but we don't.  We study Bayes’ Theorem, which demonstrates that doing moderate specificity  on low risk populations produces an overwhelming number of false positives.  But good decision-making requires more explanation.  Further, the patient who has a false alarm is often grateful for our efforts, while we all know of women diagnosed with ovarian (or breast) cancer when they were very young, and many of them die horrible deaths. 

The authors suggest that costs of this excess screening could be as much as $360 million annually across the US.  I suspect that the cost is much higher, because the authors are not counting the downstream tests initiated by the initial false positive from the inappropriate screening test. 

We clearly need more effective professional education around the efficacy of ovarian cancer screening.   The authors note also that patient education has lowered the demand for inappropriate BRCA 1 and BRCA 2 screening women worried about breast cancer, suggesting that patient education could play an important role.

By the way - good news today that colon cancer screening really DOES save lives.  The study reviewed the experience of 2602 patients who had colon polyps removed with rate of death among the general population; patients were tracked as long as 20 years, and the study showed a 53% decrease in rate of death from colon cancer among those who had the polyp removal.

We need physicians to expend more energy to promote colonoscopies, and less energy to promote screening that has not been showed to lengthen or improve life.