Contemporary pathologic characteristics and oncologic outcomes of prostate cancers missed by 6- and 12-core biopsy and diagnosed with a 21-core biopsy protocol.

International audiencePURPOSE: To assess the pathological and the oncologic outcomes of the prostate cancer (PCa) missed by 6- and 12-core biopsy protocols by using a reference 21-core scheme. MATERIALS AND METHODS: Between 2001 and 2009, all patients who had PCa detected in an initial 21-core TRUS biopsy scheme and were treated by a radical prostatectomy (RP) were included. Patients were sorted in 3 groups according to the diagnosis site: sextant (6 first cores; group 1), peripheral zone (12 first cores; group 2) or midline/transitional zone (after 21 cores; group 3). Demographics, pathological features in biopsy and RP specimens and follow-up after RP were analyzed. The 5-year progression-free survival (PFS) was studied in the 3 groups. RESULTS: During the study period, 443 patients were included. Among them, 67, 23.7 and 9.2% were, respectively, diagnosed in groups 1, 2 and 3. Among PCa diagnosed in midline/transition zone cores, 42% were intermediate or high risk. Unfavorable disease was more frequently reported in group 1 in terms of extraprostatic extension (P = 0.001), high Gleason score (P = 0.001) and progression (P = 0.001). No significant difference was observed between groups 2 and 3 in terms of pathological features in RP specimens and oncologic outcome. The 5-year PFS was 89.7% and not significantly different in patients diagnosed with a 12-core scheme compared to those diagnosed only with 21-core scheme (P = 0.332). CONCLUSIONS: Our findings emphasize that PCa diagnosed only in a 21-core protocol is at least as aggressive as PCa detected in a 12-core scheme. This study invalidates the widespread idea sustaining that cancers diagnosed by more than 12 biopsies are less aggressive