Nonpalpable Breast Lesions in a Breast Care Unit: Prospective Analysis on 2708 Consecutive Cases.

Background: Breast cancer screening increases the detection of nonpalpable breast lesions, These lesions raise specific concerns, involving radiological imaging, biopsy techniques, and pathological analysis. The objective of the study is to evaluate the management of nonpalpable breast lesions in a breast disease unit. Material and Methods : From 2001 to 2007, 2708 nonpalpable breast lesions were prospectively evaluated by a multidisciplinary team. Radiologic lesions were detected by mammography alone (71,5%), ultrasonography (27,90%), MRI (0,20%). All lesions were classified according to the BI RADS classification. Three hundred and nine (309) core needle biopsies were performed, 807 vacuum assisted biopsies, and 521 open breast biopsies. The pathologic results were correlated with surgery, rebiopsy or long-term imaging follow up. Results: The pathologic results showed 33 % of malignant lesions (DCIS, invasive carcinoma), 9 % of high risk lesions (atypical ductal or lobular hyperplasia, lobular carcinoma in situ) and 58 % of benign lesions. The prevalence of cancer as a function of BI-RADS was: BI-RADS 0 : 2,6% (4/152), BI-RADS 2: 0% (0/55), BI-RADS 3: 2,3% (17/740), BI-RADS 4: 23,4% (352/1502) et BI-RADS 5 : 78,7% (185/235). Twelve of 152 (7,9 %) high risk lesions were upgraded to malignant lesions and 34/211 DCIS (16,1%) were upgraded to invasive carcinoma after surgery. Diagnostic performance rates exhibited the following results: agreement rate=96,6%, sensibility=96,2%, overall underestimation rate=12,6%, and false-negative rate=1,6%.After vacuum assisted biopsy, one-step surgery was performed in 82,9% and after core needle biopsy in 68,4%. Conclusion : This kind of quality evaluation in community practice should be encouraged. Management of those lesions continuously evolves with the widespread of RMI and new biopsy techniques. Efforts should be made in exploring imaging-pathologic discrepancies, and in identifying predictive factors of invasion on biopsies. We currently perform a focused analysis on lesions that required two surgical steps despite a prior biopsy, in order to point out new ways to improve our practices. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6020.