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 the breast are still common. Benign biopsies should be regarded as negative events, due to their economical and psychological cost and their possible negative impact on cosmesis and on further diagnostic evaluation.

Methods: Retrospective data on benign/malignant breast biopsies ratio (B/M) were collected in 9 Italian centers for a period of 10-15 years. The time trend of B/M and its association to age or to single centers was evaluated.

Results: Overall 31,001 cases were considered. A strong 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 one center. Age standardized B/M was significantly different (P < 0.000001) between centers, ranging between 0.34 and 1.69. Multivariate analysis confirmed an independent significant association of age and center to B/M.

Conclusions: Marked differences in B/M are evident between centers, which cannot be explained by the confounding effect of age or by any apparent difference in the diagnostic protocol. The observed differences are likely ascribed to individual variations in diagnostic aggressivity. 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.