Mammography Assessment and Breast Cancers Detected in the New Hampshire Mammography Registry, 11/96 to 10/97, by Breast Imaging Reporting and Data System (BI-RADS) category
| BI-RADS Category | Baseline Mammography* | Breast Cancers Detected Rate/1000 | Anticipated Rate of Malignancy Following Biopsy | |
|---|---|---|---|---|
| Number | Percentage | |||
| 1 | 37,995 | 80.65% | 0.7 | —† |
| 2 | 4,930 | 10.46% | 1.2 | —† |
| 3 | 3,345 | 7.10% | 8.1 | <2%6–8 |
| 4 | 766 | 1.63% | 135.8 | 23%–34%12–15 |
| 5 | 76 | 0.16% | 605.3 | ≥95%1,4,12–15 |
| Total | 47,112 | 100.00% | ||
* Data derived from Poplack et. al.5
† Categories 1 and 2 are considered to be negative test results.