Doctors' biases can lead to miscalculating cancer risk

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Doctors' biases can lead to miscalculating cancer risk

Study observed primary physicians' assessments of women's risk for ovarian, colon cancer
Elizabeth Hunter

Fifty-seven percent of physicians correctly assessed female patients’ risk for ovarian cancer and 62 percent correctly assessed their risk for colon cancer in a study published recently in the Journal of General Internal Medicine.
The lead author was led by Barbara Goff, a UW professor of obstetrics and gynecology and surgical oncologist at UW Medical Center.

Incorrect risk assessment often stems from a lack of communication between patients and doctors about the patient’s family history, Goff said. She advises all patients to tell their primary care physicians about any family history of cancer, as well as any new diagnoses of cancer (or other genetically-linked diseases) within the family. She also sees electronic health records as a way to improve risk-assessment, since they can more readily depict family health trees.

The study involved physicians who provide primary care for women, such as internal medicine and family medicine specialists, and obstetrician/gynecologists. A 12-page questionnaire asked the doctors to identify patients’ level of risk for both cancers based on vignettes of patient histories. Vignettes involved histories for women with “average,” “higher than average,” and “very high” risk, as identified by accepted medical standards.

Physicians who did not accurately assess risk either overestimated risk, which can lead to overtreatment, or underestimated risk, which can result in a lack of preventive measures.
Factors that contributed to inaccurate assessments included the following.

For inaccuracies regarding ovarian cancer risk assessment: 

  • the physician’s specialty
  • the physician’s confidence in screening tests such as transvaginal ultrasound or the level of a cancer antigen
  • the physician’s age (physicians aged between 50-64 overestimated risk)
  • the physician’s inclination to follow professional organizations’ guidelines such as those from the National Cancer Institute and National Institutes of Health
  • the physician’s location (rural or small-town physicians underestimated risk) 

For inaccuracies regarding colon cancer risk assessment:

  • the physician’s gender (female physicians were more likely than male counterparts to overestimate risk)
  • the patient’s race (overestimation of risk was more likely with African-American women)
  • the patient’s personal history of breast cancer 

Physicians were more likely to overestimate colon cancer risk than ovarian cancer risk, but about 62 percent of participating physicians did assess accurately.

Mischaracterizing cancer risks has significant repercussions. Average-risk people who are instructed by physicians to get screenings may needlessly sustain psychological trauma. Moreover, extra screening for ovarian cancer and colon cancer does not result in better outcomes for either cancer, data indicates. Faulty assessments also contribute to bloated healthcare costs.