Journal of the National Cancer Institute 92(12): 971-976, 2000. is available online for subscribers.
Bobo JK, Lee NC, Thames SF
Mammography programs have received extensive study, but little is known about the outcome of clinical breast examinations (CBEs) performed in community settings. Consequently, we analyzed data from the National Breast and Cervical Cancer Early Detection Program on CBEs provided to low-income women from 1995 through 1998 and determined the percentage of CBEs considered to be abnormal, suspicious for cancer; the rates of cancer detection; and the sensitivity, specificity, and positive predictive value of CBEs.
We analyzed data from 752081 CBEs and found that 6.9% of all CBEs were coded abnormal, suspicious for cancer, and that 5.0 cancers were detected per 1000 examinations (95% confidence interval [CI] = 4.9-5.2). The values observed for sensitivity (58.8%) and specificity (93.4%) were comparable to those reported for the CBE component of clinical trials. The observed positive predictive value was 4.3%. About 74% of all records also reported mammography results. The cancer-detection rate among records reporting an abnormal CBE and normal mammography was 7.4 cancers per 1000 records (95% CI = 6. 3-8.4). When the CBE was normal but the mammography was abnormal, the rate was 42.0 cancers per 1000 records (95% CI = 39.9-44.1). When both CBE and mammography results were abnormal, the rate was 170.3 cancers per 1000 records (95% CI = 162.7-177.9). Cancer detection could not be attributed entirely to CBE or mammography on 38% of the records in the latter subset because the tests were performed on the same day.
CBEs performed in community-based screening programs can detect breast cancers as effectively as CBEs performed in clinical trials and may modestly improve early-detection campaigns.
Rheinische Friedrich- Wilhelms- Universität Bonn