Benign breast lesions at risk of developing cancer--a challenging problem in breast cancer screening programs: five years' experience of the Breast Cancer Screening Program in Verona (1999-2004).

Background: Cytology and core-needle biopsies are not always sufficient to exclude malignancy in benign breast lesions (BBL) that are at risk of developing cancer, and open biopsy often is mandatory. In screening programs, open biopsies performed for lesions that are at risk of developing malignancy are considered benign. The authors of this report evaluated the impact of the screen-detected BBL at risk of developing cancer that were counted in the quota of benign breast open biopsies in the Breast Cancer Screening Program of Verona.

Methods: Benign open biopsies were subdivided into 4 groups according to their risk of developing cancer: Histo1, normal histology; Histo2, 'pure' BBL (fibroadenoma, fibrocystic disease, mastitis, adenosis); Histo3, BBL with a low risk of developing cancer (radial scar, papilloma, papillomatosis, phyllodes tumor, mucocele-like lesion); and Histo4, BBL with a high risk of developing cancer (atypical columnar cell hyperplasia, atypical ductal hyperplasia, atypical lobular hyperplasia).

Results: Of 510 open biopsies, 83 biopsies were benign, and the ratio of benign to malignant biopsies was 1:5. Histo1 was observed in 4.8% of all benign open biopsies, Histo2 was observed in 37.4%, Histo3 was observed in 31.3%, and Histo4 was observed 26.5%.

Conclusions: BBL at risk of developing cancer may be numerous in screening programs. It is inappropriate to include BBL at risk of developing cancer in the overall benign open biopsy rate. The authors propose separating pure BBL from lesions at higher risk of developing cancer. To date, there is no evidence to support the premise that detecting high-risk proliferative lesions leads to benefits in terms of reduced mortality; however, these lesions need to be counted separately for future evaluations.