Combining clinical breast exam with mammography can result in higher cancer detection rates and sensitivities as well as more false-positives, according to a study published online Aug. 31 in the Journal of the National Cancer Institute.
According to Anna M. Chiarelli, PhD, of the Population Studies and Surveillance Division, Cancer Care Ontario in Toronto, and colleagues, there has been an ongoing controversy whether adding a clinical breast exam to mammography enhances the accuracy of breast screening.
For the purposes of the study, the authors compared the accuracy of screening in centers that offer clinical breast exams along with mammography to those centers that offer just mammography.
The researchers examined a cohort of 290,230 women between the ages of 50 and 69, who were screened at regional cancer centers within the Ontario Breast Screening Program between Jan. 1, 2002 and Dec. 31, 2003.
They found that sensitivity of referrals was higher for women who were screened at regional cancer centers or affiliated centers that offered a clinical breast exam in addition to mammography than for women screened at affiliated centers that did not offer a clinical breast exam. But, women without cancer who were screened at centers that offered both clinical breast exams and mammography also had a higher false-positive rate than those women at centers that offered just mammography.
"Overall, we found higher breast cancer detection rates and sensitivities for [a clinical breast exam] referral than those previously found in other community-based studies, which suggests that the accuracy of [a clinical breast exam] can be improved in screening programs that offer high-quality [clinical breast exams] by specially trained nurses," the authors wrote.
However, Chiarelli and colleagues added that the benefits of adding clinical breast exams need to be weighed against the costs and risks associated with false positives, as well as the anxiety involved in putting patients through additional evaluations.
In an accompanying editorial, Mary B. Barton, MD, of the Agency for Healthcare Research and Quality (AHRQ) in Rockville, Md., and Joann G. Elmore, MD, of the University of Washington School of Medicine in Seattle, wrote that there is a "steep price" for the potential gains of adding clinical breast exam to mammography.
For a theoretical population of 10,000 women between the ages of 50 and 69 years, the addition of a clinical breast exam would lead to the detection of breast cancer in only four women whose cancer would be missed by mammography. However, adding a clinical breast exam would also lead to false-positive results for an additional 219 women, they wrote.
"More answers are needed on the role of [a clinical breast exam] in breast cancer screening before definitive recommendations for or against its use can be made," Barton and Elmore wrote. "While we wait for those answers, the data presented by Chiarelli et al. suggest that [a clinical breast exam] must be done well if it is to be done at all, with the acknowledgment that overall referrals and false-positive results will increase."