Initial Experience with Transperineal Prostate Biopsy: A Painless Learning Curve
Aaron Berkenwald, MD, Luke Sebel, MD, Ph.D, Kristian Stensland, MD, MPH, Alireza Moinzadeh, MD, MHL, William Faust, MD.
Lahey, Burlington, MA, USA.
Title: Initial Experience with Transperineal Prostate Biopsy: A Painless Learning CurveIntroductionTransperineal Prostate Biopsy (TPBx) is gaining traction in urology. We evaluated our initial institutional experience using the PrecisionPoint system (Perineologic, Cumberland, MD), focusing on the learning curve, patient reported pain, clinically significant cancer detection rates (csCDR) and complications, compared to standard biopsy methods. Material & MethodsAfter IRB approval, a retrospective review of all consecutive patients undergoing prostate biopsy (June 2019-March 2021) at a single institution was performed. Procedure time and pain scores were recorded for the first 253 pt. TPBx procedural times were modeled using single phase exponential decay fit by least squares regression. A 10-point Numerical Rating Scale (NRS) was used to record for pain during probe insertion, anesthetic block, biopsy and post-procedure. csCDR for the entire cohort (Gleason Grade Group ≥2) was compared between TPBx, transrectal ultrasound guided biopsy (TRUSBx) and TRUS/MRI fusion biopsy (MRIBx) using Fisher’s exact test. Complications were compared using chi-square.
Results: 34% (234/692) of patients underwent TPBx. TPBx proficiency was achieved by the 20’th patient with a plateau procedural time of 9.1 minutes (95% CI 8.56-9.89) compared to 8.5 for TRUSBx and 12.4 for MRIBx. Median reported NRS scores for TPBx vs. TRUSBx or MRIBx fusion showed a difference during anesthetic injection (4.0 vs. 2.0 and 3.0 respectively, p=0.007) and probe insertion (2.0 vs. 3.0 and 3.0 respectively, p=0.06). This held true for sub-analysis of patients who had ≥1 prior biopsy. For screening biopsies, csCDR for MRIBx, TPBx and TRUSBx were 41.6%, 37.5% and 28.9% respectively (p=0.01). MRIBx was better than TRUSBx in detecting csCancer (p=0.03) but failed to show superiority over TPBx (p=0.2). Complication rates between TPBx and pooled TRUS biopsies were not significantly different (2.6% vs. 3.4%, p=0.51). Two sepsis events occurred in both groups.
Conclusions: The learning curve for TPBx is short with proficiency achieved after approximately 20 cases. TPBx patients report similar levels of discomfort for all aspects of the procedure compared to standard transrectal approach. csCDR rates between MRIBx and TPBx were not significantly different. Complication rates were similar between TPBx and pooled transrectal approach including 2 sepsis events in both cohorts, suggesting that while sepsis events are rarely reported in the TPBx approach, they are not impossible.
Table 1: Demographics and complication rates
| TPBX | TRUSBx | MRIBx | P value | |
| N | 234 | 162 | 296 | |
| Age (mean (SD)) | 64.6 (7.4) | 64.0 (6.5) | 65.3 (7.2) | 0.19 |
| PSA (median [25th, 75th percentile]) | 6.4[4.9, 9.9] | 6.5[4.5, 9.3] | 7.5[5.3, 10.0] | 0.03 |
| Prostate Size (cm3)(median [25th, 75th percentile]) | 45.0[31.0, 60.0] | 42.4[29.5, 59.9] | 45.1[32.6, 60.5] | 0.43 |
| Purpose (n (%)) | <0.0001 | |||
| Cancer screening | 209 (89.3) | 143 (88.3) | 201 (71.0) | |
| Active surveillance | 25 (10.7) | 19 (11.7) | 86 (29.1) | |
| DRE (n (%)) | 0.01 | |||
| Normal | 162 (74.7) | 113 (70.6) | 238 (82.4) | |
| Abnormal | 55 (25.4) | 47 (29.4) | 51 (17.7) | |
| Complication (n (%)) | TPBX | All Transrectal | ||
| N | 234 | 457 | ||
| No | 228 (97.4) | 441 (96.5) | ||
| Yes | 6 (2.6) | 16 (3.4) | 0.51 | |
| Sepsis | 2(0.9) | 2 (0.5) | 0.50 | |
Table 2: NRS pain scores during biopsy procedure
| All Patients | TPBx | TRUSBx | MRIBx | P value |
| N | 80 | 67 | 94 | |
| Probe insertion (median (IQR) minutes) | 2 (0-4) | 3 (1.5-4.8) | 3 (1.1-4.9) | 0.06 |
| Anesthetic block | 4 (2-6) | 2 (1-4) | 3 (1-4) | 0.007 |
| Biopsy | 3 (1-5) | 2 (0-4) | 2.5 (1-4) | 0.11 |
| Post-procedure | 0 (0-2) | 0 (0-1) | 0 (0-1.3) | 0.20 |
| Procedural time (median time (min) (IQR)) | 11 (9-13.3) | 7.5 (6-11) | 12 (11-14) | <0.001 |
| Patients with ≥ 1 prior biopsy | TPBx | TRUSBx | MRIBx | P value |
| N | 21 | 38 | 81 | |
| Probe insertion (median NRS score (IQR)) | 1.5 (0-4) | 3 (1.5-5) | 3 (1.5-5) | 0.01 |
| Anesthetic block | 4 (2-6) | 2.5 (1-4) | 3 (1-4.1) | 0.02 |
| Biopsy | 3 (1-4) | 2 (0-4) | 2 (1-4) | 0.36 |
| Post-procedure | 0 (0-2) | 0 (0-1) | 0 (0-1.5) | 0.15 |
| Procedural time (median time (min) (IQR)) | 11 (9-13) | 7.5 (6-11) | 12 (11-14) | <0.001 |
Table 3: Cancer detection rates of TPBx and TRUSBx compared to MRIBx (nsCancer = nonsignificant cancer)
| All Patients | N | No Cancer (n (%)) | nsCancer (n (%)) | csCancer (n (%)) | P Value |
| MRIBx | 295 | 93 (31.5) | 67 (22.7) | 135 (45.8) | Reference |
| TPBx | 232 | 87 (37.5) | 59 (25.4) | 86 (37.1) | 0.13 |
| TRUSBx | 161 | 85 (52.8) | 31 (19.3) | 45 (28.0) | <0.001 |
| Screening only | N | No Cancer | nsCancer | csCancer | P value |
| MRIBx | 209 | 84 (40.2) | 38 (18.2) | 87 (41.6) | Reference |
| TPBx | 208 | 77 (37.0) | 53 (25.5) | 78 (37.5) | 0.2 |
| TRUSBx | 142 | 76 (53.5) | 25 (17.6) | 41 (28.9) | 0.03 |
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