TIME TRENDS OF BENIGN MALIGNANT BREAST BIOPSY RATIOS - A MULTICENTER ITALIAN STUDY/

Aims and background: Although they have been decreasing over time due to improved specificity of diagnostic assessment, benign biopsies of t he breast are still common, Benign biopsies should be regarded as nega tive events, due to their economical and psychological cost and their possible negative impact on cosmesis and on further diagnostic evaluat ion, Methods: Retrospective data on benign/malignant breast biopsies r atio (B/M) were collected in 9 Italian centers for riod of 10-15 years , The time trend of B/M and its association to age or to single center s was evaluated. Results: Overall 31,001 cases were considered, A stro ng association of B/M to age was evident (average B/M values were 5.0, 1.3, 0.6, and 0.2 for women aged <40, 40-49, 50-59, and >59 years). A significant trend of decreasing B/M over time was observed only for o ne center, Age standardized SIM was significantly different (P<0.00000 1) between centers, ranging between 0.34 and 1.69. Multivariate analys is confirmed an independent significant association of age and center to B/M. Conclusions: Marked differences in B/M are evident between cen ters, which cannot be explained by the confounding effect of age or by any apparent difference in the diagnostic protocol. The observed diff erences are likely ascribed to individual variations in diagnostic agg ressivity. A progressive increase of the predictive value of calls for surgical biopsy may be achieved over time and centers with a high B/M should make every effort to optimize their performance. Acceptable (< 40=5, 40-49=1.5, 50-59=0.75, >59=0.3) and desirable (2.5, 0.75, 0.35, 0.15) age specific reference standards for B/M are proposed.