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Surgeons may influence genetic testing for breast cancer
Women with early-stage breast cancer appeared more likely to undergo genetic testing if their attending surgeon made frequent genetic testing and counseling referrals and expressed confidence in discussing genetic testing, according to results from a population-based study.
“Genetic testing can help inform decisions about breast cancer treatment and prevention of future cancers in patients and their families,” Steven J. Katz, MD, MPH, professor of general medicine at University of Michigan, said in a press release. “It’s important to ensure patients who need this information receive it as part of the treatment discussion, regardless of the surgeon they see.”
Guidelines recommend genetic testing for patients with breast cancer at high risk for pathogenic mutation. Approximately one-third of patients undergo genetic testing.
Research has suggested that surgeon attitudes and practices related to genetic testing vary and may influence whether a patient undergoes testing.
As a result, patients with newly diagnosed breast cancer with similar indications for testing may have different probabilities of undergoing testing depending on the surgeon who treats them.
“The surge of genetic testing in cancer care is a major challenge for surgeons,” Katz said. “There is a lack of consensus around guidelines and approach to testing, and legitimate uncertainty about its value in guiding treatment, especially with newer genes whose cancer risks are not well defined.”
Katz and colleagues hypothesized that individual attending surgeons might impact variability in testing based on their attitudes about genetic testing and counseling.
To test this, researchers surveyed 7,303 women with stage 0 to 2 breast cancer who received treatment between July 2013 and August 2015. Researchers linked survey responses to SEER clinical data that contained genetic testing information.
Among the 5,080 respondents (69.6%; mean age, 61.4 years), 98% identified an attending surgeon (n = 488). Researchers sent surveys to surgeons toward the end of the patient data collection period, 377 of whom (mean age, 53.8 years; 24.3% women) completed the survey, for a response rate of 77.3%.
On average, there were 10.5 (range, 1-84) patients per surgeon. Surgeons had been in practice a mean 20.9 years, and 28.9% treated more than 50 new breast cancer cases annually.
Researchers developed a Tendency to Test Scale based on seven questions to measure each surgeon’s likelihood to order genetic testing and counseling in different scenarios. Four questions regarded a patient who is deemed by the surgeon to be a candidate for testing, two referred to a scenario in which the surgeon does not recommend testing but the patient requests it, and one item assessed the surgeon’s confidence in discussing genetic testing.
Approximately one-third of patients (34.5%) had elevated risk for mutation carriage and 27% of the total patient sample underwent genetic testing. Among women who underwent testing, 13.8% had average pretest risk and 52.1% had high pretest risk.
Surgeons who often or always delayed surgery to obtain genetic testing (35.2%), as well as those confident in discussing genetic testing with their patients (50.2%), had higher scores on the Tendency to Test Scale, an indication of positive correlation.
Researchers then evaluated correlations based on Tendency to Test Scale scores that differed from the mean, where a mean –1 represented tendency against testing and a mean +1 represented tendency for testing.
Patients, regardless of their pretest risk, had more than twofold increased likelihood for undergoing testing if their attending surgeon scored a mean +1 above the mean test rate (OR = 2.48; 95% CI, 1.85-3.31).
In a model that accounted for surgeon volume, likelihood for undergoing genetic testing increased by 1.88 (95% CI, 1.49-2.38) for each mean +1 increase in scale score. Approximately one-third (34.1%) of surgeon variation in testing was related to patient volume and surgeon attitudes about genetic testing and counseling.
“This may reflect that surgeons with greater specialization in breast cancer have more resources to offer testing, including timely access to genetic counselors,” researchers wrote.
Patients with high pretest risk who saw a surgeon at the 5th percentile of surgeon distribution had a 26.3% (95% CI, 21.9-31.2) probability of undergoing testing, compared with a 72.3% (95% CI, 66.7-77.2) probability for women who saw a surgeon in the 95th percentile.
“Our results highlight the need for greater outreach to surgeons in the community to build consensus about approaches to genetic risk evaluation and results management for patients with breast cancer, particularly as evidence emerges about the utility of genetic testing in clinical and demographic subgroups,” researchers wrote.
Although the study results may seem “obvious,” consideration of the data “triggers the controversial discussion of population-based BRCA genetic testing for all women,” Lisa A Newman, MD, MPH, FACS, FASCO, director of the breast oncology program at Henry Ford Health System, wrote in a related editorial.
“Katz [and colleagues] demonstrate that a surgeon’s comfort level with genetic testing and extent of experience diagnosing and treating breast cancer influence the likelihood that a woman with a BRCA mutation-associated breast cancer will ever learn of her carrier status,” she wrote. “Consequently, some patients may be denied information that might have affected decisions regarding risk-reducing breast and/or ovarian surgery.”
Population-based genetic testing may be able to overcome disparities in genetic counseling.
“By proving a pattern that was predictable, [Katz and colleagues] have initiated a larger conversation that has yet to be concluded,” Newman wrote. – by Melinda Stevens
Disclosures: The authors and Newman report no relevant financial disclosures.
