Breast cancer detection, false-positive rates higher in centers offering clinical breast exams plus mammography

Detection rates and sensitivity were higher for centers that offered clinical breast exams in addition to screening with mammography; however, false-positive rates were higher as well, according to the results of a recently published study.

In an editorial accompanying the study, Mary B. Barton, MD, of the Agency for Healthcare Research and Quality in Rockville, Md., and Joann G. Elmore, MD, of the University of Washington School of Medicine in Seattle, wrote, “More answers are needed on the role of clinical breast exam in breast cancer screening before definitive recommendations for or against its use can be made.

“While we wait for those answers, the data presented by Chiarelli et al suggest that clinical breast exam must be done well if it is to be done at all, with the acknowledgement that overall referrals and false-positive results will increase,” they said.

To compare the accuracy of referrals for further assessment based on mammography alone or mammography with clinical breast exam, researchers analyzed data from 290,230 women aged 50 to 69 who were screened through the Ontario Breast Screening Program between January 2002 and December 2003. Follow-up was conducted at 12 months.

At initial screening, the sensitivity rate for referrals was 94.9% for regional centers with clinical breast exam and 94.6% for affiliated centers with clinical breast exam vs. 88.6% for affiliated centers without it. At subsequent screening, the sensitivity rate was 94.9% for regional centers, 91.7% for affiliated centers with clinical breast exam and 85.3% for affiliated centers without.

At initial screening, the false-positive rate was 12.5% for regional centers with clinical breast exam, 12.4% for affiliated centers with clinical breast exam vs. 7.4% for affiliated centers without it. At subsequent screening, the false-positive rate was 6.3% for regional centers, 8.3% for affiliated centers with it and 5.4% for affiliated centers without.

“For 10,000 women screened, there would be an additional four cancers detected, and of the 9,937 women without cancer, there would be an additional 219 false-positive screens. Therefore, for each additional cancer detected by clinical breast exam per 10,000 women, there would be 55 additional false-positive screens,” the researchers wrote.

Chiarelli AM. J Natl Cancer Inst. 2009;101:1236-1243.