Growth rate and characteristics of breast cancers detected by ultrasonography screening

Breast cancer screening was carried out at our institution in a ''Human Dock'' style health check, by inspection and palpation, together with ultrasonography. Breast cancers detected were reviewed and the utility of ultrasonography was evaluated. A total of 14,063 women underwent the screening and the results were good, with a recall rate of 3.4%, a cancer detection rate of 0.30%, and a positive predictive value of 8.7%. Of 42 breast cancers detected by ultrasonography, 30 (71%) were 1.5 cm or less in diameter. For breast cancers detected by inspection and palpation, the detection rate for small cancers measuring 1.5 cm or less was 33% (10 out of 30 women), and 100% (12 women) for tumors measuring more than 1.5 cm. The cancer detection rate by mammography was 39% (9 out of 23 cancers) for tumors measuring 1.5 cm or less, and 91% (10 out of 11 cases) for those larger than 1.5 cm. Thus cancer detection by ultrasonography was optimal for tumors measuring 1.5 cm or less. Histologically proven lymph node metastasis was positive in 8 (25%) of 32 patients, among whom some had primary cancers measuring 1.5 cm or less. Tumor volume doubling time (TVDT) was measurable in 10 women; there was no change in size in one instance, and in the others TVDT was 4.8 to 32.5 months (mean 15.5 months), small cancers approximately 1 cm in size having a long TVDT. In women whose cancer size could be determined twice or more, TVDT tended to be short when a cancer measured about 1 cm or more. Cancers with a long TVDT showed low histological malignancy, and thus detection of breast cancers with a long TVDT at screening appears to be rewarding. (author)