Individual surgeon genetic testing rates differed substantially. Depending on the surgeon, a woman with a high risk for carrying a pathogenic mutation had a 26.3% to 72.3% likelihood of receiving the guideline-recommended testing. Dr Katz said that this shows undertesting is occurring, because not all of the patients who should receive genetic testing currently are, and, for a patient with a clinical indication for genetic testing, it “very much” matters which surgeon she goes to.
Because the study included only patients and surgeons from the state of Georgia and Los Angeles County, the results may not be generalizable to the rest of the United States, although the study authors wrote that the study population is large and diverse.
The variation in genetic testing rates was explained by several factors. Twenty percent of the variability was attributed to patient risk factors, meaning patients who had a high risk of a pathogenic mutations were more likely to undergo genetic testing. Surgeon attitudes toward genetic testing was another component, making up 17.4% of the variability. In fact, the likelihood of a patient receiving testing more than doubled if she went to a surgeon with a high propensity for ordering genetic testing.
Patient volume also contributed to variation, with the highest-volume surgeons being more likely to recommend genetic testing. Even after controlling for surgeon attitudes, patient volume was still associated with receipt of genetic testing.
The reason for such high variability in genetic testing ordered by surgeons may be due to the lack of consensus around when to recommend genetic testing, the authors reasoned.
“We have to reduce that variability by building consensus around the use of the testing because once you build that consensus, doctors do the right thing,” said Dr Katz. “Right now we don’t have sufficient consensus about the value and the timing of the genetic testing after diagnosis, and I think that’s going to change.”
- Katz SJ, Bondarenko I, Ward KC, et al. Association of attending surgeon with variation in the receipt of genetic testing after diagnosis of breast cancer [published online July 3, 2018]. JAMA Surg. doi: 10.1001/jamasurg.2018.2001
- Kurian AW, Griffith KA, Hamilton AS, et al. Genetic testing and counseling among patients with newly diagnosed breast cancer. JAMA. 2017;317(5):531-534.