The Surgical Management of Large Prostatic Adenoma

Introduction

Benign prostatic hyperplasia (BPH) is a prevalent disease, affecting 22% of men < 60 years old, and 45% of men 70-80 years old [1]. When BPH symptoms are refractory to medical management, surgical intervention is recommended. Optimal surgical management for large prostatic adenoma, defined as prostate mass > 100 g or volume > 80 cc, is controversial. While open simple prostatectomy (OSP) remains the gold-standard surgical management for severe BPH, the procedure is associated with significant morbidity, encouraging the use of other surgical options. This blog will discuss the surgical management of large prostatic adenoma, with emphasis on several alternatives to OSP, including bipolar TURP, holmium laser therapy, photoselective vaporization of the prostate (PVP), and robot assisted laparoscopic simple prostatectomy (RASP).

Open Simple Prostatectomy (OSP)

OSP is the gold standard surgical management for high volume (> 80 cc) prostatic adenoma. Advantages of this approach include more complete removal of prostatic adenoma under direct visualization, lower re-treatment rates, and no risk of TUR syndrome. A randomized controlled trial comparing transvesical open simple prostatectomy (TVP) with TURP for prostates > 80 cc demonstrated significant reduction in IPSS scores at 12 months post-op for the TVP group. Unfortunately, the peri-operative blood transfusion rate was 11% and 14% for the TVP and TURP arms, respectively (Figure 1) [2]. This morbidity associated with OSP has encouraged urologists to seek other alternatives for the management of large prostatic adenoma.

Figure 1: Complications for both TURP (n= 35) and Transvesical Open
Simple Prostatectomy (TVP) (n = 34). Ou et al. Urology 2010.

TURP

Monopolar TURP has been the gold standard surgical management for prostates 30-80 mL, but concerns regarding TUR syndrome and excessive bleeding prevent its routine use in larger prostatic adenoma. For this reason, many studies have focused on Bipolar TURP, which enables the use of normal saline irrigation with no risk of TUR syndrome. In a recent prospective, randomized trial comparing Bipolar TURP vs. OSP for prostates > 80 cc, Bipolar TURP was found to resect significantly less prostatic adenoma mass despite having similar pre-operative prostate size to the OSP arm. However, a significantly less hemoglobin drop, blood transfusion rate, and hospital stay was found in the Bipolar TURP arm [3].

Holmium Laser Therapy

Holmium laser therapy emits light at 2100 nm in pulses. This causes tissue water vaporization with limited (0.4 mm) tissue penetration. Because the procedure uses normal saline for irrigation, there is no risk for TUR syndrome manifested by dilutional hyponatremia. Laser settings commonly cited in the literature include 2-2.5 J and 40-50 Hz [4]. Several retrospective studies have found significant 6 month post-op reduction in IPSS scores for prostates greater than 75, 125, and 175 g [4-6]. Furthermore, these studies reported low peri-operative blood transfusion rates of 1.9-3.5%, which is significantly less than the reported OSP average blood transfusion rate of 8.5% or greater. For this reason, holmium laser therapy is often cited in the literature as having prostate “size independent” effectiveness.

Photoselective Vaporization of the Prostate (PVP)

Photoselective Vaporization of the Prostate (PVP) is commonly referred to as the Greenlight laser, as it vaporizes tissue at a wavelength of 532 nm. Because the laser is selectively absorbed by hemoglobin, the relatively fibrous prostatic capsule is resistant to absorption, making this procedure an attractive alternative to OSP. The current generation of the Greenlight laser is the 180 W XPS laser. The power has been increased from previous generations in order to improve adenoma removal and lower re-treatment rates. A multi-institutional prospective trial that looked at nearly 1,200 patients (2/3 with > 80 cc prostates; 1/3 with < 80 cc prostates) who underwent 180 W XPS laser therapy found that the larger prostate cohort maintained a mean IPSS reduction of 19 points at 6, 12, and 24 months post-op [7]. However, significantly more of the > 80 cc prostate cases had to be converted to TURP, most commonly due to bleeding that obscured the visual field. Therefore, PVP appears to be an effective, but imperfect alternative to OSP for large prostatic adenoma.

Robot assisted laparoscopic Simple Prostatectomy (RASP)

Robot assisted simple prostatectomy (RASP) appears to be a very attractive alternative to OSP, with the hope that it would produce the functional results of OSP while reducing the associated morbidity, including hospital length of stay, perioperative hemorrhage, and blood transfusion rates. The transvesical approach provides excellent visualization of the extent of the prostatic adenoma, while preventing injury to the ureteral orifices during incision of the bladder mucosa (Figure 2).

Figure 2: Transvesical RASP: Incision in bladder mucosa distal to the ureteral orifices.
Screen shot credit: Misop Han, M.D. Brady Urological Institute at Johns Hopkins Hospital.

Data from the Brady Urological Institute comparing RASP to OSP found reductions in estimated blood loss, blood transfusions, and hospital length of stay for the RASP arm (Figure 3). Although there was no significant difference in pre-operative prostate volume by transrectal ultrasound measurements, RASP had similar adenoma resection weights as compared to OSP. A review that looked at 13 RASP studies found an overall blood transfusion rate of 3.5% [8].

Figure 3. RASP vs. OSP Peri-operative Outcomes.
Brady Urological Institute at Johns Hopkins Hospital.

An edited video of a robot assisted laparoscopic simple prostatectomy performed at Johns Hopkins Hospital can be found below.

Key Points

• Open simple prostatectomy is the gold standard surgical management for large prostatic adenoma
• Bipolar TURP may remove less adenoma than OSP
• HoLEP has prostate “size independent” effectiveness
• PVP is effective but bleeding my obscure visualization
• RASP is an excellent alternative for severe BPH for those well versed in robotic radical prostatectomy

This blog was written by Bijan W. Salari, a medical student at Wright State University Boonshoft School of Medicine. Bijan recently finished a four-week sub-internship at the Brady Urological Institute and gave a presentation to the department on "The Surgical Management of Large Prostatic Adenoma" from which this blog is inspired. Bijan  is looking forward to a career in urology.

REFERENCES
1. Speakman et al. Burden of male lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) - focus on the UK. BJU Int. 2015 Apr;115(4):508-19. doi: 10.1111/bju.12745. Epub 2014 Oct 16.
2. Ou et al. A randomized trial of transvesical prostatectomy versus transurethral resection of the prostate for prostate greater than 80 mL. Urology. 2010 Oct;76(4):958-61. doi: 10.1016/j.urology.2010.01.079. Epub 2010 Apr 15.
3. Geavlete et al. Bipolar vaporization, resection, and enucleation versus open prostatectomy: optimal treatment alternatives in large prostate cases? J Endourol. 2015 Mar;29(3):323-31. doi: 10.1089/end.2014.0493. Epub 2014 Sep 17.

4. Krambeck et al. Holmium laser enucleation of the prostate for prostates larger than 175 grams. J Endourol. 2010 Mar;24(3):433-7. doi: 10.1089/end.2009.0147.
5. Matlaga et al. Holmium laser enucleation of the prostate for prostates of >125 mL. BJU Int. 2006 Jan;97(1):81-4.
6. Kuo et al. Holmium laser enucleation of prostate (HoLEP): the Methodist Hospital experience with greater than 75 gram enucleations. J Urol. 2003 Jul;170(1):149-52.
7. Hueber et al. Photoselective Vaporization of the Prostate for Benign Prostatic Hyperplasia Using the 180 Watt System: Multicenter Study of the Impact of Prostate Size on Safety and Outcomes. J Urol. 2015 Aug;194(2):462-9. doi: 10.1016/j.juro.2015.03.113. Epub 2015 Apr 4.
8. Patel et al. Robotic-assisted Simple Prostatectomy: Is there Evidence to go Beyond the Experimental Stage? Curr Urol Rep (2014) 15:443.