Increase in Cancer Detection and Recall Rates with Independent Double Interpretation of Screening Mammography

OBJECTIVE: This study reports the increase in cancer detection that resulted from independent double interpretation of screening mammography. Although screening mammography is used to detect occult breast cancer, its sensitivity and specificity are limited. Double interpretation of screening mammograms is one proven method used to improve detection, with studies reporting a 5-15% increase in cancer detection. MATERIALS AND METHODS: Two radiologists independently double-interpreted 25,369 screening mammograms performed from November 1998 to April 2000. The second reviewer could add but could not delete recalls. The subsequent additional diagnostic imaging was performed in the same way whether generated from the first or the second reviewer. The outcome of each case was determined. The cancer detection rate and sensitivity are reported. RESULTS: Double interpretation of screening mammograms detected 143 breast malignancies. The second reviewer found nine (6.3%) of 143 cancers and all except one were stage 0 or I. The sensitivity increased from 74.4% to 79.4% with double interpretation. The second reviewer contributed 371 of the 3591 total recalls, increasing the absolute rate of recalls by 1.5% (371/25,369) and the relative rate by 11.5% (371/3220). Six hundred seventy-two total biopsies were performed; 38 were generated by the second interpretation. CONCLUSION: The relative increase in cancer detection as a result of the second reviewer is 6.3%, similar to the 5-15% reported in the literature. All but one of the nine additional cancers detected were in the early stages.