HER2/neu gene determination in women screened for breast carcinoma: how screening programs reduce the skyrocketing cost of targeted therapy.

Few data on Human Epidermal Growth Factor Receptor 2 (HER2)-positive breast carcinomas have been reported for screen-detected breast carcinoma. Assessing the impact of a targeted intervention with anti-HER2 inhibitors on costs is required in order to plan for better strategies in screening programs. A total of 54,472 women were screened and 323 cases were found to be invasive cancer. We performed immunophenotypical-fluorescent in situ hybridization (FISH) analysis. Among 153 evaluable breast carcinomas, tumours displayed a 3+ scoring status 3+ in 16 (10%), 2+ in 12 (8%), 1+ in 29 (19%) and 0 in 96 (63%) of cases, respectively. All 3+ HER2+ cases and 2/12 2+ (17%) cases exhibited HER2/neu gene amplification, the remaining cases did not. In contrast to the higher incidence reported at the population level, 20-30% HER2-positive cases for metastatic carcinomas, and only 11% of the screen-detected breast carcinomas displayed HER2/neu gene amplification. Breast cancer detection by screening programs hijacks the skyrocketing cost of the use of targeted therapy in HER2-positive carcinoma.