Intraoperative Frozen Section of the Prostate Reduces the Risk of Positive Margin Whilst Ensuring Nerve Sparing in Patients with Intermediate and High-Risk Prostate Cancer Undergoing Robotic Radical Prostatectomy: First Reported UK Series

Abstract

Introduction: Nerve sparing during robotic radical prostatectomy (RRP) considerably improves post-operative potency and urinary continence as long as it does not compromise oncological outcome. Excision of the neurovascular bundle (NVB) is often performed in patients with intermediate and high risk prostate cancer to reduce the risk of positive surgical margin raising the risk of urinary incontinence and impotence. We present the first UK series outcomes of such patients who underwent an intra-operative frozen section (IOFS) analysis of the prostate during RRP allowing nerve sparing.

Patients and methods: We prospectively analysed the data of 40 patients who underwent an IOFS during RRP at our centre from November 2012 until November 2014. Our IOFS technique involved whole lateral circumferential analysis of the prostate during RRP with the corresponding neurovascular tissue. An intrafascial nerve spare was performed and the specimen was removed intra-operatively via an extension of the 12 mm Autosuture™ camera port without undocking robotic arms. It was then painted by the surgeon and sprayed with "Ink Aid" prior to frozen section analysis. The corresponding NVB was excised if the histopathologist found a positive surgical margin on frozen section.

Results: Median time to extract the specimen, wound closure and re-establishment of pneumoperitoneum increased the operative time by 8 min. Median blood loss for IOFS was 130 ± 97 ml vs. 90 ± 72 ml (p = NS). IOFS was not associated with major complications or with blood transfusion. PSM decreased significantly from non-IOFS RRP series of 28.7 to 7.8% (p < 0.05). Intra-operative PSM on the prostate specimen was seen in 8/40 margin analysis (20%) leading to an excision of the contra-lateral nerve bundle. On analysis of the nerve bundle on a paraffin embedded block, 6 nerve bundle matched tumor on the specimen whereas 2 NVB were retrospectively removed unnecessarily in our series. All 40 patients have undetectable PSA at a mean follow up of 21.2 months (SD 7.79). Functional data at 18 months confirms a reduction in the urinary incontinence from 37% in the IOFS group vs 57% in the non-IOFS group (p = NS). IOFS technique has resulted in a significant increase in intravesical nerve sparing in both T2/T3 patients with intermediate and high risk prostate cancer when appropriately counselled and selected (T2 from 100% in the IOFS group versus 67% and T3 from 100% in the IOFS group to 42%) (p < 0.05).

Conclusion: Introduction of the IOFS analysis during intrafascial nerve spare RRP has reduced PSM and the rate of urinary incontinence.

Keywords: Prostate adenocarcinoma; RRP.

Figures

Fig. 1

Autosuture™ port.

Fig. 2

Placement of Autosuture™ port during Robotic Radical Prostatectomy with placement of interrupted 2/0 Ethibond™ sutures.

Fig. 3

Advancement of ports when pneumoperitoneum collapses prior to removal of specimen intra-operatively.

Fig. 4

Appearance of specimen on excision intraoperatively (a), Intrafascial NS for lower risk disease (b) Interfascial NS for intermediate / high risk disease (c).

Fig. 5

Sectioning of prostate.

Fig. 6

Cryostamp processing of the prostate.

Fig. 7

Paraffin wax block of prostate specimen.

Fig. 8

Positive painted surgical margin (a. Low power) and (b. High power).

Fig. 9

Location of positive surgical margins during robotic radical prostatectomy.

Fig. 10

Preoperative MRI pre robotic prostatectomy. a Tumor has early breach of capsule and very close to right neurovascular bundle. b Asymmetric thickening of Left Neurovascular bundle, possible sign of involvement.