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.