Does Size Really Matter? The Impact of Prostate Volume on the Efficacy and Safety of GreenLight HPS™ Laser Photoselective Vaporization of the Prostate

Abstract

Purpose:

To evaluate the efficacy and safety of GreenLight HPS™ laser photoselective vaporization of the prostate (PVP) for the treatment of benign prostatic hyperplasia (BPH) in patients with different prostate volumes.

Patients and Methods:

Between July 2006 and February 2011, 207 consecutive patients were identified from a prospectively maintained urologic database. Based on preoperative prostate volume measured by transrectal ultrasonography, patients were stratified into two groups: ≥80 cc (group 1, n=57) and <80 cc (group 2, n=150). Transurethral PVP was performed using a 120W GreenLight HPS side-firing laser system. American Urological Association Symptom Score (AUASS), quality-of-life (QoL) score, maximum flow rate (Qmax), and postvoid residual (PVR) volume were measured preoperatively and at 1 and 4 weeks and 3, 6, 12, 18, 24, and 36 months postoperatively.

Results:

Among the preoperative parameters evaluated, there were significant differences (P<0.05) in the incidence of preoperative urinary retention (1: 24.6%; 2: 7.3%), serum prostate-specific antigen level (1: 4.5±2.7; 2: 1.8±1.9 ng/mL), QoL (1: 4.2±1.1; 2: 4.7±0.9), and mean prostate volume (1: 118.1±37.9; 2: 48.5±15.5 cc), while AUASS, Qmax, and PVR were similar (P>0.05) between groups. Significant differences (P<0.05) in laser use (1: 22.8±13.3; 2: 10.4±6.4 minutes) and energy usage (1: 152.7±90.6; 2: 70.9±44.8 kJ) were also noted. Clinical outcomes (AUASS, QoL, Qmax, and PVR) showed immediate and stable improvement from baseline (P<0.05) within each group, but no significant differences between the two groups were observed during the follow-up period (P>0.05). The incidence of adverse events was low and similar in both cohorts.

Conclusions:

These results suggest that prostate volume has little effect on the efficacy and safety of GreenLight HPS laser PVP, and that this technique remains a viable surgical option for BPH, irrespective of preoperative prostate volume.

Introduction

B enign prostatic hyperplasia (BPH) is the most common cause of lower urinary tract symptoms (LUTS) in the aging male and will increase in socioeconomic and medical importance at a time of increased life expectancy and aging of the baby boomer generation. Because of progression of BPH and failure of maximal medical therapy, up to one-third of patients will eventually need surgical intervention.¹ Despite being the gold standard by which all other methods for treating BPH are compared,² transurethral resection of the prostate (TURP) continues to be associated with significant morbidity—eg, perioperative hemorrhage or transurethral resection (TUR) syndrome, particularly in patients with larger prostate volumes.³

With evolution of minimally invasive surgical options, the 120W GreenLight HPS^™ (High Performance System) laser photoselective vaporization of the prostate (PVP) has been demonstrated to be a safe and effective treatment for patients with BPH in comparison with TURP.⁴ This system uses a 1064 nm neodynium:yttrium-aluminum-garnet laser beam that is emitted through a lithium triborate (LBO) crystal that doubles the frequency and halves the wavelength to 532 nm, producing a higher power (120W) laser than its 80W predecessor, the potassium-titanyl-phosphate (KTP) laser generated through a KTP crystal. The GreenLight HPS laser is strongly absorbed by oxyhemoglobin (absorption coefficient 10²/cm), but hardly at all by water (absorption coefficient 10⁻⁴/cm), making it an ideal laser for transurethral vaporization of hyperplastic prostate tissue.⁵ Light absorption by hemoglobin is converted to thermal energy that leads to target tissue temperature elevation and ultimately results in the tissue vaporization witnessed during PVP.⁶

The GreenLight HPS laser PVP has gained increasing acceptance worldwide because of the similar clinical outcomes garnered compared with TURP with distinct advantages over the latter.⁴ Short- and midterm clinical outcomes of the GreenLight HPS laser PVP have been reported.^7,8 Although a few studies have focused on patients with larger prostate volumes and exhibited positive results, they only had short-term follow-up (<6 mos), calling into question the durability of these results.^9,10

In the present study, we review our experience with GreenLight HPS laser PVP to determine if prostate volume has an impact on the efficacy and safety of this technique with a maximum follow-up of 36 months.

Patients and Methods

Approval for this study was granted by the Institutional Review Board at the University of Oklahoma Health Sciences Center. Prospectively collected data from the records of consecutive patients who were diagnosed with LUTS secondary to BPH who underwent GreenLight HPS laser PVP by a single surgeon (CW) at a tertiary care referral center between July 2006 and February 2011 were reviewed. Surgical indications were in accordance with BPH guidelines of the American Urological Association.¹¹

The preoperative evaluation included American Urological Association Symptom Score (AUASS), quality of life (QoL) score, Sexual Health Inventory for Men (SHIM), American Society of Anesthesiologists (ASA) risk score, complete medical history, physical examination, urine and blood sample analysis including serum prostate specific antigen (PSA) level, uroflowmetry (minimum 150 mL volume) for maximum flow rate (Qmax), postvoid residual (PVR), cystourethroscopy, and transrectal ultrasonography (TRUS) measurements of prostate volume (calculated using three multiplanar linear measurements) and configuration (measured from the bladder neck in the midsagittal plane and confirmed by cystourethroscopy). If patients were found to have an elevated serum PSA value or abnormal digital rectal examination (DRE), TRUS-guided prostate biopsies were performed preoperatively to exclude prostate cancer (PCa). Patients with PCa, urethral strictures, bladder tumors, or bladder dysfunction from neurologic disorders were excluded from the study.⁷

Based on the prostate volume as measured by TRUS, patients were stratified into two groups: ≥80 cc (group 1, n=5 7) and <80 cc (group 2, n=150). Transurethral PVP was performed using a 120W GreenLight HPS side-firing laser system (American Medical Systems, Minnetonka, Minnesota) as described previously.⁵ Ongoing anticoagulant medications (acetylsalicylic acid, clopidogrel, and warfarin) were recommended to be discontinued if possible. Preoperative antibiotic prophylaxis was provided and general or spinal anesthesia was used. A 23F continuous-flow cystoscope with a 30-degree lens was used with the laser set at 120W for vaporization and 30W for coagulation. Room temperature physiologic saline was used as the irrigation fluid. A 20F urethral catheter was placed at the end of procedure and a voiding trial was performed 2 hours postoperatively. If patients were unable to urinate, a urethral catheter was replaced before discharge, and the patient returned to our outpatient clinic for a second voiding trial the following morning.⁸ All PVP procedures were performed on an outpatient basis because patients were discharged home the same day of surgery.

Perioperative parameters, including laser use, delivered energy, operative time, and serum hemoglobin and sodium levels were recorded. Clinical outcomes (AUASS, QoL, Qmax, PVR, and SHIM) were prospectively assessed for changes from baseline at 1 and 4 weeks and 3, 6, 12, 18, 24, and 36 months. Serum PSA and TRUS measurements were obtained at the 3-month follow-up, with subsequent serum PSA determinations performed as medically indicated. Adverse event data were collected and analyzed.

Continuous variables were presented as mean±standard deviation and range, categorical variables were presented as percentage. Statistical analysis was performed using the Excel 2007 statistical software package and GraphPad Instat3 software. The Student t test, chi-square test, and analysis of variance were used for statistical validation, with a two-sided P<0.05 considered to indicate statistical significance.

Results

Baseline demographic information for the entire 207 patient cohort is presented in Table 1. There was no significant difference in the baseline data (AUASS, SHIM, Qmax, PVR, and ASA score), and mean follow-up was similar between the two groups (1: 16.3±17.2; 2: 13.1±13.5 mos, P=0.168). Patients in group 1 were older, and a larger percentage of these patients were in urinary retention preoperatively (1: 24.6%; 2: 7.3%, P=0.002). More patients in group 1 (1: 21.1%; 2: 0.1%, P=0.003) were taking 5α-reductase inhibitors, while similar patients in each group used an α-blocker or combination therapy with an α-blocker+5α-reductase inhibitor. A similar percentage of men in each group were also taking oral antiplatelet agents or anticoagulants (acetylsalicylic acid, clopidogrel, and warfarin). All patients were able to discontinue the anticoagulants (acetylsalicylic acid, 7 days; clopidogrel, 10 days; warfarin, 5 days) before surgery and resumed after surgery when hematuria resolved.

Table 1.

Patient Demographics

Parameter	Group 1	Group 2	P value
Age (y), mean±SD (range)	72.1±8.3 (53–87)	67.1±9.6 (44–89)	0.001
ASA, mean±SD (range)	2.3±0.6 (1–4)	2.4±0.7 ( 1–4 )	0.700
Urinary retention, n (%)	14 (24.6)	11 (7.3)	0.002
Medications for BPH, n (%)	43 (75.4)	97 (64.7)	0.183
α–blocker	21 (36.8)	56 (37.3)	1.000
5α–reductase inhibitor	12 (21.1)	9 (0.1)	0.003
α–blocker+5α–reductase inhibitor	10 (17.5)	32 (21.3)	0.699
Anticoagulation, n (%)	14 (24.6)	59 (39.3)	0.052
PSA (ng/mL), mean±SD (range)	4.5±2.7 (0.7–11.6)	1.8±1.9 (0.1–11.7)	0.001
AUASS, mean±SD (range)	21.5±6.3 (10–34)	23.1±6.2 (8–35)	0.122
QoL, mean±SD (range)	4.2±1.1 (3–6)	4.7±0.9 (3–6)	0.001
SHIM, mean±SD (range)	13.0±8.1 (1–25)	12.7±7.7 (1–25)	0.824
Qmax (mL/s), mean±SD (range)	9.2±3.1 (2.4–14.6)	9.4±4.1 (1.9–24.6)	0.780
PVR (mL), mean±SD (range)	95.0±139.0 (0–659)	70.6±120.0 (0–866)	0.283
Trilobe prostate, n (%)	47 (82.5)	44 (29.3)	0.001
Prostate volume (cc), mean±SD (range)	118.1±37.9 (80–263)	48.5±15.5 (21–79)	0.001

SD=standard deviation; ASA=American Society of Anesthesiologists; BPH=benign prostatic hyperplasia; PSA=prostate-specific antigen; AUASS=American Urological Association Symptom Score; QoL=quality of life; PVR=postvoid residual.

Patients with larger glands tended to have trilobe prostates (1: 82.5%; 2: 29.3%, P=0.001), lower QoL (1: 4.2±1.1; 2: 4.7±0.9, P=0.001), and higher serum PSA (1: 4.5±2.7; 2: 1.8±1.9 ng/mL, P=0.001). Patients who presented with a serum PSA value ≥4 ng/mL accepted a TRUS-guided prostate biopsy that confirmed benign pathology. One 81-year-old patient with previous negative prostate biopsy results and a stable PSA level of 10.1 ng/mL for 15 years and one 75-year-old patient with a PSA value of 6.1 ng/mL receiving chronic anticoagulation medication for atrial fibrillation in group 1, and one 85-year-old patient with a PSA value of 5.9 ng/mL in group 2 deferred prostate biopsy.

Longer mean laser time (P=0.001), operative time (P=0.001), and higher energy usage (P=0.001) were needed for treating larger prostates. The mean estimated rates of prostate vaporization (average of TRUS volume change divided by laser time) were significantly different between the two groups (1: 3.7±2.9; 2: 2.8±1.4 mL/min, P=0.042). Significant change between pre- and postoperative serum hemoglobin and hematocrit (P<0.05) values were noted in each arm, but no differences between the two groups, respectively. Postoperative hyponatremia did not develop in any patient, and no blood transfusion was necessary. All procedures were performed as same-day outpatient surgery. There were 27 (47.3%) patients in group 1 and 88 (58.7%) patients in group 2 who were catheter-free at hospital discharge (P=0.161), while catheter-free rates increased to 87.7% and 93.3%, respectively, the day after surgery (P=0.255). Twelve (1: 6; 2: 6) patients were able to void 1 week postsurgery. The remaining five (1: 1; 2: 4) patients needed clean intermittent catheterization for an elevated PVR, all of whom presented with refractory urinary retention. Two patients needed three fibers and one needed two fibers in group 1, while two fibers were needed in three patients in group 2 (Table 2).

Table 2.

Perioperative Parameters

Parameter	Group 1	Group 2	P value
Laser utilization (min), mean±SD (range)	22.8±13.3 (2.6–80.3)	10.4±6.4 (1.6–49.0)	0.001
Operative time (min), mean±SD (range)	54.3±30.7 (6–165)	25.5±16.7 (6–105)	0.001
Energy usage (kJ), mean±SD (range)	152.7±90.6 (11.0–547.5)	70.9±44.8 (10.7–343.0)	0.001
Vaporization efficiency, mean±SD
Volume change/time (mL/min)	3.7±2.9	2.8±1.4	0.042
Volume change/energy (mL/kJ)	0.6±0.7	0.4±0.4	0.052
Concurrent cystolitholapaxy, n (%)	2 (3.5)	2 (1.3)	0.304
Multiple fibers, n (%)	3 (5.3)	3 (2.0)	0.153
Hemoglobin (g/dL), mean±SD (range)
Preoperative	14.7±1.3 (10.5–16.9)	14.3±1.4 (10.0–17.4)	0.193
Postoperative	13.7±1.1^a (11.2–15.6)	13.7±1.2^b (10.1–15.8)	0.859
Serum sodium (mmol/L), mean±SD (range)
Preoperative	138.7±2.2 (131–143)	138.5±3.3 (127–151)	0.672
Postoperative	138.6±2.3 (133–144)	138.4±2.5 (132–143)	0.551
Catheter-free, n (%)	27 (47.3)	88 (58.7)	0.161
Catheter <23 h, n (%)	50 (87.7)	140 (93.3)	0.255

P=0.001, ^b P=0.001.

SD=standard deviation.

Symptomatic improvement of LUTS was noted immediately after urethral catheter removal, with significant improvements in AUASS, QoL, Qmax, and PVR from baseline (P<0.05) that were durable to 36 months in each group. No significant difference in clinical outcomes was noted between the two groups during the follow-up interval. Postoperative SHIM remained stable compared with baseline in each group and was similar (P>0.05) between the two groups (Table 3). Mean prostate volume measured by TRUS (single operator blinded to the baseline prostate volume) showed a similar reduction in both groups (1: 49.9%; 2: 52.1%, P=0.375) at the 3-month follow-up. Excluding the patients (1: 22; 2: 41) who were on a 5α-reductase inhibitor of minimum 6 months' duration preoperatively, the mean serum PSA reduction 3 months postsurgery (1: 29.0%; 2: 33.1%, P=0.595) was also similar between the two groups.

Table 3.

Clinical Outcomes

	Mean±SD
Clinical outcomes n1, n2	Preoperative 57, 150	1 wk 48, 133	4 wk 47, 122	3 mos 41, 112	6 mo 33, 93	12 mos 27, 78	18 mos 18, 41	24 mos 17, 30	36 mos 16, 19
AUASS
Group 1	21.5±6.3	8.1±5.6^a	6.4±4.0^a	4.6±3.1^a	4.0±2.7^a	3.6±2.4^a	3.6±1.9^a	3.4±2.3^a	3.5±2.2^a
Group 2	23.1±6.2	7.1±3.4^a	6.0±3.2^a	5.2±3.5^a	4.5±2.0^a	4.0±2.0^a	3.2±1.8^a	3.2±1.7^a	3.2±1.8^a
P value	0.122	0.163	0.559	0.313	0.249	0.346	0.510	0.754	0.674
QoL
Group 1	4.2±1.1	1.4±1.4^a	1.0±1.2^a	0.5±0.8^a	0.7±1.3^a	0.4±0.6^a	0.2±0.4^a	0.3±0.6^a	0.1±0.4^a
Group 2	4.7±0.9	1.2±0.9^a	0.9±0.9^a	0.5±0.8^a	0.5±0.5^a	0.4±0.9^a	0.1±0.4^a	0.2±0.4^a	0.1±0.5^a
P value	0.001	0.152	0.501	0.986	0.181	0.692	0.482	0.521	0.846
Qmax
Group 1	9.2±3.1	20.3±7.3^a	21.3±8.0^a	21.8±6.2^a	21.7±7.8^a	21.2±5.1^a	22.3±4.2^a	22.3±8.9^a	19.4±4.7^a
Group 2	9.4±4.1	21.0±6.9^a	22.5±7.4^a	22.7±7.8^a	21.8±6.7^a	22.2±8.3^a	22.6±6.7^a	21.3±4.8^a	20.7±7.1^a
P value	0.780	0.553	0.362	0.515	0.969	0.571	0.882	0.612	0.554
PVR
Group 1	95.0±139.0	51.9±57.9^a	49.0±46.1^a	37.9±45.6^a	34.4±49.3^a	30.4±31.0^a	31.2±27.5^a	34.1±32.0^a	37.9±33.9^a
Group 2	70.6±120.0	37.7±73.0^a	36.0±35.6^a	34.0±68.2^a	24.2±34.8^a	27.4±31.3^a	26.7±34.5^a	22.6±23.4^a	23.8±24.6^a
P value	0.238	0.225	0.073	0.738	0.247	0.778	0.955	0.070	0.190
SHIM
Group 1	13.0±8.1	12.1±8.0	14.2±8.7	15.1±8.5	12.6±9.1	13.5±8.4	11.4±8.2	12.0±9.0	13.4±9.2
Group 2	12.7±7.7	13.0±8.0	12.8±8.1	14.1±8.3	14.6±8.1	15.6±8.3	12.06±8.8	13.8±9.7	15.1±7.1
P value	0.824	0.523	0.361	0.546	0.303	0.312	0.623	0.548	0.602

p<0.05

More patients in group 1 (1: 7%; 2: 0.7%, P=0.021) had clinically nonsignificant intraoperative bleeding that was successfully controlled with the coagulation mode of the laser system without the need of conversion to TURP or open surgery. The incidence of adverse events was low and similar between the two groups: Clinically nonsignificant hematuria (<7 day: P=1.000; ≥7 day: P=0.538), UTI (P=0.220), transient irritative voiding symptoms (P=0.350), de novo retrograde ejaculation (P=0.238), delayed hematuria (P=0.304), and bladder neck contracture (P=0.476). Fortunately, no urinary incontinence or urethral strictures were reported during the follow-up interval (Table 4).

Table 4.

Adverse Events

Adverse events	Group 1	Group 2	P value
Intraoperative, n (%)
Nonsignificant bleeding	4 (7.0)	1 (0.7)	0.021
Blood transfusion	0	0
Prostate capsule perforation	0	0
TUR syndrome	0	0
Early postsurgery (<30 day), n (%)
Nonsignificant hematuria <7 d	34 (59.6)	89 (59.3)	1.000
Nonsignificant hematuria ≥7 d	5 (8.7)	9 (6.0)	0.538
Temporary catheterization	1 (1.8)	4 (2.7)	1.000
Clean intermittent catheterization	1 (1.8)	4 (2.7)	1.000
Urinary tract infection	4 (7.0)	4 (2.7)	0.220
Transient irritative voiding symptoms	3 (5.3)	3 (2.0)	0.350
De novo retrograde ejaculation	6 (18.8)	23 (31.5)	0.238
Urinary incontinence	0	0
Late postsurgery (≥30 day), n (%)
^aDelayed hematuria	2 (3.5)	2 (1.3)	0.304
Bladder neck contracture	1 (1.8)	1 (0.7)	0.476
Urethral stricture	0	0

Normal hematuria evaluation (CT urography and cystoscopy).

TUR=transurethral resection; CT=computed tomography.

Discussion

Patients with large prostate volumes (eg, greater than 80 cc) present a unique and challenging problem for the urologic surgeon. Traditionally, open simple prostatectomy was recommended for most patients with prostate volumes greater than 80 to 100 cc.¹¹ This procedure, however, continues to be associated with significant morbidity¹² and may not be an ideal intervention for patients with medically compromised conditions. Holmium laser enucleation of the prostate represents the endoscopic equivalent of open simple prostatectomy and has been proved safe and effective for managing large glands by experienced surgeons.¹³ This technique, however, is associated with a steep learning curve and is yet to be accepted universally by most endourologists because of the technically demanding nature of the procedure.

Since the initial report by Hai and Malek in 2003,¹⁴ there has been a rapid acceptance and dissemination of GreenLight laser technology throughout the urologic community. Although PVP performed with the KTP laser was initially proposed for the treatment of high-risk patients receiving anticoagulation,¹⁵ it rapidly achieved broader clinical use. This original 80W KTP laser has evolved to a higher-powered 120W LBO GreenLight HPS laser and more recently the 180W LBO GreenLight XPS system.¹⁶ Our initial results with the GreenLight HPS laser PVP were optimistic, having excellent clinical efficacy and safety outcomes in both short- and midterm follow-up.^7,8

In the present study, patients in group 1 were older and had better QoL scores, which may be related to different perceptions of LUTS and a lower expectation of satisfactory voiding in older patients. We did not find prostate volume to be associated with differences in postoperative AUASS, Qmax, and PVR between both groups. In one of the first reported studies that evaluated opposing treatment modalities in patients with larger prostate volumes (>80 cc), Alivizatos and associates¹⁷ randomized men to undergo PVP vs open simple prostatectomy. Although operative time was significantly longer with PVP, these patients experienced a significantly shorter length of catheterization, hospitalization, and a lower rate of postoperative blood transfusion. Perhaps more importantly, there were no significant differences in postoperative Qmax, PVR, International Index for Erectile Function score or International Prostate Symptom Score (IPSS) between groups at 12 months of follow-up. Recently, Al-Ansari and colleagues⁴ reported their midterm results in a randomized trial comparing the safety and efficacy of GreenLight HPS prostatectomy vs standard TURP. There was a dramatic and comparable degree of improvement in Qmax, PVR, and IPSS for both groups throughout the entire 36-month follow-up. Interestingly, they reported an 11% reoperation rate in the PVP group over 36 months compared with only 1.8% in the TURP group. In a posthoc analysis, they found that prostate volume was >80 cc in all failures and therefore recommended that PVP be avoided in this patient subset. We have not had to re-treat any patient for recurrent adenoma, urethral stricture, or bladder neck contracture during 36 months of follow-up but certainly will continue to evaluate this phenomenon as our data set matures.

As expected, the laser use and operative time were significantly longer, and the energy delivered was markedly greater for larger volume prostates. The laser fibers are factory-programmed to have a limit of 275 kJ. A total of three (5.3%) patients in group 1 needed more than one laser fiber (three fibers in two patients and two fibers in one patient), which was comparable to the results reported by Tasci and coworkers¹⁸ in which 9.63% of patients with large prostates (≥70 cc) needed a second laser fiber. Recently, Son and associates¹⁹ introduced a modified vaporization-resection technique, which has the purported advantage of saving laser time and energy, especially in patients with larger prostate volumes. Interestingly, vaporization efficiency in our study (3.7 mL/min and 0.6 mL/kJ) was three-fold higher than the results (0.97 mL/min and 0.25 mL/kJ) reported by Son and colleagues.¹⁹ When comparing vaporization efficiency between groups, we found a statistically significant difference favoring larger glands (1: 3.7±2.9; 2: 2.8±1.4 mL/min, P=0.042), possibly because of the increased vascularity found in larger prostates, subsequently leading to greater absorption of the GreenLight laser.

All of our GreenLight HPS laser PVP procedures were able to be successfully performed on an outpatient basis. Comparable rates of patients (1: 47.3%; 2: 58.7%, P=0.161) in both groups were able to successfully void 2 hours postsurgery and were discharged from hospital without a urethral catheter. Likewise, a similar percentage of patients in both groups (1: 87.7%; 2: 93.3%, P=0.255) became catheter-free the day after surgery, suggesting that prostate size did not impact the length of catheterization. Almost immediate and durable improvement of both subjective (AUASS, QoL) and objective (Qmax, PVR) voiding parameters have been recorded and clinical outcomes were similarly noticeable for both groups for up to 36 months of follow-up.

Safety is always a paramount concern when treating men with larger prostate volumes. Nonsignificant intraoperative bleeding was encountered more often in group 1 (1: 7.0%; 2: 0.7%, P=0.021) and was able to be controlled appropriately with the coagulation mode of the GreenLight HPS laser set at 30W. The incidence of postoperative hematuria, irritative voiding symptoms, UTI, urinary retention necessitating transient recatheterization, and retrograde ejaculation were low and similar between the two groups (P>0.05). No patient needed a blood transfusion, and no episode of prostate capsular perforation or TUR syndrome was noted in either group in our study.

The incidence of UTI was slightly higher in group 1 (1: 7.0%; 2: 2.7%, P=0.220), most likely secondary to a more extensive tissue vaporization performed in larger glands. The incidence of transient irritative voiding symptoms was 5.3% in group I, lower than the 22% reported by Rajbabu and coworkers²⁰ in their study of prostates >100 mL treated by KTP laser PVP. The etiology of transient storage symptoms after PVP is multifactorial and may occur as a result of surgical experience, previous treatment with a 5α-reductase inhibitors, or degree of laser fiber degradation.²¹ We believe that limiting coagulation during vaporization plays an integral role in decreasing transient urgency and dysuria after PVP. Our results suggest that the clinical outcomes of the 120W GreenLight HPS laser PVP are independent of prostate size, even for prostate volumes >80 cc.

Lack of specimen for pathologic evaluation has been a concern regarding the PVP technique, with the possible risk of overlooking a prostate cancer despite a normal preoperative DRE and serum PSA level. Therefore, continued postoperative surveillance by DRE and serum PSA value is advised. One of the shortcomings of our prospectively collected data set is the pending follow-up of patients at various time intervals. Only 47 (1: 30; 2: 17) and 35 (1: 16; 2: 19) patients reached the 24- and 36-month follow-up interval, respectively, at the time of this writing. Factors that may have contributed to this include the insufficient time interval postsurgery and the geographic distribution of our patients (many of whom reside >3 hours from our institution), limiting follow-up compliance.

Conclusions

Our results suggest that prostate volume has little effect on the efficacy and safety of the 120W GreenLight HPS laser PVP. Almost immediate and durable improvement in clinical outcome measurements can be achieved in patients regardless of prostate size. Further substantiation of these results by data from large prospective trials or continued long-term follow-up would be of benefit.

Footnotes

Acknowledgments

This work was supported in part by the Endourological Society and Cook Urological Corporation. We are thankful for the contributions from Glenn M. Sulley, R.N., Colleen F. Davis, M.A., DeAnna J. Kuykendall, M.A., Raquel Carranco, M.A., and Maria E. Gonzalez, M.A.

Disclosure Statement

Carson Wong, M.D., is a consultant for American Medical Systems, Inc. For the remaining authors, no competing financial interests exist.

Abbreviations Used

References

Levy

, Samraj

. Benign prostatic hyperplasia: When to “watch and wait,” when and how to treat. Cleve Clin J Med, 2007; 74,suppl 3:S15–S20.

Smith

, Patel

. Transurethral resection of the prostate revisited and updated. Curr Opin Urol, 2011; 21:36–41.

Reich

, Gratzke

, Bachmann

et al. Morbidity, mortality and early outcome of transurethral resection of the prostate: A prospective multicenter evaluation of 10,654 patients. J Urol, 2008; 180:246–249.

Al-Ansari

, Younes

, Sampige

et al. GreenLight HPS 120-W laser vaporization versus transurethral resection of the prostate for treatment of benign prostatic hyperplasia: A randomized clinical trial with midterm follow-up. Eur Urol, 2010; 58:349–355.

Wong

, Araki

, Tonkin

. High-power potassium-titanyl-phosphate or lithium triboride laser photoselective vaporization prostatectomy for benign prostatic hyperplasia: A systematic approach. J Endourol, 2007; 21:1141–1144.

Elzayat

, Elhilali

. Laser treatment of symptomatic benign prostatic hyperplasia. World J Urol, 2006; 24:410–417.

Spaliviero

, Araki

, Wong

. Short-term outcomes of GreenLight HPS laser photoselective vaporization prostatectomy (PVP) for benign prostatic hyperplasia (BPH) J Endourol, 2008; 22:2341–2347.

, Strom

, Spaliviero

, Wong

. Intermediate outcomes of GreenLight HPS laser photoselective vaporization prostatectomy for symptomatic benign prostatic hyperplasia. J Endourol, 2011; 25:1037–1041.

Woo

. Photoselective vaporization of the prostate using the 120-W lithium triborate laser in enlarged prostates (>120 cc) BJU Int, 2011; 108:860–863.

10.

Woo

, Reich

, Bachmann

et al.

Outcome of GreenLight HPS 120-W laser therapy in specific patient populations: Those in retention, on anticoagulants, and with large prostates (≥80ml)

Eur Urol, 2008; suppl 7:378–383.

11.

McVary

, Roehrborn

, Avins

et al. Update on AUA guideline on the management of benign prostatic hyperplasia. J Urol, 2011; 185:1793–1803.

12.

Lewis

, Burgess

, Hudd

, Matthews

. Open or transurethral surgery for the large prostate gland. Br J Urol, 1992; 69:598–602.

13.

Kuntz

, Lehrich

. Transurethral holmium laser enucleation versus transvesical open enucleation for prostate adenoma greater than 100 gm: A randomized prospective trial of 120 patients. J Urol, 2002; 168:1465–1469.

14.

Hai

, Malek

. Photoselective vaporization of the prostate: Initial experience with a new 80 W KTP laser for the treatment of benign prostatic hyperplasia. J Endourol, 2003; 17:93–96.

15.

Reich

, Bachmann

, Siebels

et al. High power (80W) potassium-titanyl-phosphate laser vaporization of the prostate in 66 high risk patients. J Urol, 2005; 173:158–160.

16.

Fournier

, Perrouin-Verbe

, Papin

, Deruelle

. [Usefulness of real time transrectal ultrasonography to monitor the Greenlight XPS(®) (180W) laser prostatectomy.] (Fre) Prog Urol, 2011; 21:383–386.

17.

Alivizatos

, Skolarikos

, Chalikopoulos

et al. Transurethral photoselective vaporization versus transvesical open enucleation for prostatic adenomas >80mL. 12-mo results of a randomized prospective study. Eur Urol, 2008; 54:427–437.

18.

Tasci

, Ilbey

YÖ

, Luleci

et al. 120-W GreenLight laser photoselective vaporization of prostate for benign prostatic hyperplasia: Midterm outcomes. Urology, 2011; 78:134–140.

19.

Son

, Ro

, Min

et al. Modified vaporization-resection for photoselective vaporization of the prostate using a GreenLight high-performance system 120-W Laser: The Seoul technique. Urology, 2011; 77:427–432.

20.

Rajbabu

, Chandrasekara

, Barber

et al. Photoselective vaporization of the prostate with the potassium-titanyl-phosphate laser in men with prostates of >100 mL. BJU Int, 2007; 100:593–598.

21.

Matoka

, Averch

. Predictability of irritative voiding symptoms following photoselective laser vaporization of the prostate. Can J Urol, 2007; 14:3710–3714.