Diagnostic performance of initial transperineal 14-core prostate biopsy to detect significant cancer

To investigate cancers missed by extended transperineal (TP) 14-core biopsy (TP14PBx) and examined its diagnostic performance.

We evaluated 744 men with prostate-specific antigen (PSA) levels in the range 2.5-20 ng/mL or abnormal digital rectal examination underwent three-dimensional 26-core prostate biopsy (3D26PBx), a combination of TP14PBx and transrectal 12-core biopsy (TR12PBx), at initial biopsy. Of 269 patients diagnosed with cancer, 127 subsequently underwent radical prostatectomy (RP). Cancers were grouped into TP-positive cancers (detected through TP14PBx) and TP-negative cancers (those not detected through TP14PBx but detected through TR12PBx). Clinicopathological characteristics and cancer locations of TP-negative cancers were evaluated. For cancer location analysis, the prostate was divided into apex, midprostate, and base regions.

Thirty-seven (14 %) TP-negative cancers were found in 269 biopsy-positive cancers. Median number of positive cores in TP-negative cancers was significantly lower than that in TP-positive cancers (1 vs. 5, p < 0.001). TP-negative cancers had biopsy Gleason score (GS) of 7 or less in 87 % of cases and had significantly lower biopsy GS than those of TP-positive cancers (p = 0.028). Of 20 TP-negative cancers treated with RP, 70 % (14/20) were insignificant cancers (GS <4+3, volume <0.5 cc, and organ-confined disease). Of all significant cancers treated with RP, 6 % (6/99) were missed by TP14PBx. TP-negative cancers treated with RP were located more frequently in the apex than in the base (85 vs. 20 %, p < 0.001).

Initial TP14PBx provides sufficient detectability of significant cancers despite a small risk of missing cancers located in the prostate apex.