Introduction:

Sextant prostate biopsies have previously been extended to 12-core template biopsies (TBx) to improve detection rates of prostate cancer (PCa). It is unclear if this holds true in the current era when 12-core TBx are being performed in conjunction with MRI/ultrasound fusion biopsies (FBx). The 2016 AUA consensus statement on FBx suggests the continued synchronous performance of a 12-core TBx due to the risk of missing clinically significant PCa (csPCa) in up to 23% of patients. We sought to determine if the number of TBx cores could be reduced in order to decrease patient discomfort (and possibly risk of infection and bleeding) without affecting detection rates in the setting of combined TBx/FBx.

Methods:

A retrospective analysis was performed on patients undergoing first time combined 12-core TBx/FBx at Columbia University Medical Center by a single Urologist for elevated PSA or abnormal digital rectal exam from 2015-2018. The medial and lateral 6 cores of the 12-core TBx were separately censored to simulate biopsy results of a 6-core TBx. McNemar’s test was performed to assess if FBx plus 6-core biopsy had similar diagnostic ability as FBx plus 12-core biopsy.

Results:

Overall, 395 patients were identified. Figure 1 shows the distribution of pathologic findings for three groups, panel a-c (FBx plus 12-core TBx, and the two sets of FBx plus 6-core TBx). Of 209 patients with benign findings or Gleason 3+3 disease on targeted FBx only, csPCa (defined as Gleason ≥3+4) was detected in 31 patients (15%) on 12-core TBx (panel a). When the medial vs. lateral 6 cores of the 12-core TBx were censored, clinically significant disease would have been missed in 11 (35%) vs. 8 (26%) of the 31 patients (panel b and c). McNemar’s test confirmed that omitting 6 of the 12 template biopsy cores resulted in a statistically significant decrease of csPCa detection rates (p=0.0026 and p=0.013 for medial and lateral templates, respectively).

Conclusion:

A reduction in the number of template biopsy cores from 12 to 6 at the time of fusion biopsy would result in a decreased ability to detect csPCa. Therefore, continued performance of 12-core TBx is required even in conjunction with a commonly performed MRI/US FBx. However, a prospective randomized study would need to be performed to confirm these findings in a true sextant vs 12-core TBx/FBx setting.

Funding: n/a