Are 10-, 10-12-, or > 12-mm prostate biopsy core quality control cutoffs reasonable?

To explore the role of prostate biopsy core length on prediction of index tumor clinical significance and localization on radical prostatectomy (RP) and time to recurrence, hypothesizing 10-, 10-12-, or > 12-mm minimum core as potential biopsy quality control.

Assessed 2424 prostate biopsy cores and corresponding RP of 202 patients submitted to the first set of 12 cores prostate biopsy between 2010 and 2015. Analyzed biopsy core length, age, prostate volume (PV), free and total PSA ratio, PSA density, RP index tumor clinical significance, extension, localization, surgical margins, and cancer control. Prostate biopsy confronted to surgical specimens defined Gleason grade-grouping system (1-5) agreement.

Median age was 63.7 years, PSA 10.1 ng/dl, PSA density 28%, and mean follow-up 5 years. Recurrence was identified in 64 (31.7%) patients and predicted by PSA > 10 at time of diagnosis (p = 0.008), seminal vesicle invasion (p = 0.0019), core tumor percentage (p = 0.033), and tumor localization predominantly in the prostate base (p = 0017). The mean core length was longer in index tumor positive cores (p = 0.043) and in tumors classified as clinically insignificant (p = 0.011), without impact on tumor localization (basal vs apical p = 0.592; left vs. right p = 0.320). Biopsy core length categories (≤ 10, 10-12 and > 12 mm) did not significantly impact Gleason grade-grouping agreement or time to recurrence (p > 0.05). Core length was not significantly different in all Gleason grade-groupings 1-5 (p = 0.312).

Prostate biopsy core length impacts tumor characterization; however, 10 mm minimum core length and even 10-12- and > 12-mm categories failed as a biopsy quality control in our data.