Clinically Significant Prostate Cancer Detection with Various Prostate Sampling Schemes Based on Different csPCa Definitions

Background: Combining targeted biopsy (TB) with systematic biopsy (SB) is currently recommended as the first-line biopsy method by the European Association of Urology (EAU) guidelines in patients diagnosed with prostate cancer (PCa) with an abnormal magnetic resonance imaging (MRI). The combined SB and TB indeed detected an additional number of patients with clinically significant prostate cancer (csPCa); however, it did so at the expense of a concomitant increase in biopsy cores. Our study aimed to evaluate if ipsilateral SB (ipsi-SB) + TB or contralateral SB (contra-SB) + TB could achieve almost equal csPCa detection rates as SB + TB using fewer cores based on a different csPCa definition. Methods: Patients with at least one positive prostate lesion were prospectively diagnosed by MRI. The combination of TB and SB was conducted in all patients. We compared the csPCa detection rates of the following four hypothetical biopsy sampling schemes with those of SB + TB: SB, TB, ipsi-SB + TB, and contra-SB + TB. Results: The study enrolled 279 men. The median core of SB, TB, ipsi-SB + TB, and contra-SB + TB was 10, 2, 7 and 7, respectively; they all differed significantly from SB + TB (P < 0.001). ipsi-SB + TB detected significantly more patients with csPCa than contra-SB + TB based on the EAU guidelines (P = 0.042). ipsi-SB + TB and contra-SB + TB detected almost equal number of csPCa on the basis of the Epstein criteria (P = 1.000). Compared with SB + TB, each remaining method detected significantly fewer patients with csPCa regardless of the definition (P < 0.001) except ipsi-SB + TB, which achieved an almost equivalent csPCa detection rate to that of SB + TB on the grounds of D1 (P = 0.066). Conclusions: ipsi-SB + TB could detect significantly more patients with csPCa than contra-SB + TB and acquire an almost equivalent csPCa detection rate to that of SB + TB using significantly fewer cores when csPCa was defined as International Society for Urological Pathology (ISUP) 2 or higher.