A Study of Breast Cancer Undetectable by Mammography or Ultrasonography

In 89 breast cancer lesions found during clinical breast cancer screening with combined usage of mammography (MMG) and Ultrasonography (US) between February 1995 and August 2002, we found 20 cases were negative for MMG and 13 were negative for US detection. In this study we reexamined those cases of breast cancer undetectable either by MMG or breast US. The 11 of the 20 MMG negative cases, lesions were still undetectable by secondary extended examination using MMG, however, we found 9 lesions were positive for MMG by refined technique of delineation. In the 12 US negative lesions, a secondary extended examination performed using US showed 7 lesions were positive for detection; the remaining 5 lesions were still negative for US examination. In summary, of the 89 breast cancer lesions it failed to detect 14 lesions (15.7%) by MMG, and 10 lesions (11.5%) by US in a course of clinical breast cancer screening.