Photoselective vaporization with the green light laser vs transurethral resection of the prostate for treating benign prostate hyperplasia: a systematic review and meta-analysis

Authors


Correspondence: Xingang Cui or Jingfei Teng, Shanghai Changzheng Hospital, Second Military Medical University, Department of Urology, Fengyang 415, Shanghai 200003 China.

e-mail: cuixingang@163.com; tengjingfei@yahoo.cn

Abstract

What's known on the subject? and What does the study add?

  • Despite high morbidities, TURP is still considered as the ‘gold standard’ for treatment of BPH. Photoselective vaporization of the prostate (PVP) is a promising technique that is emerging as a possible alternative to TURP. However, there remains some debate about the advantages of PVP over TURP and whether PVP will be able to replace TURP as the first-line surgical treatment.
  • We conducted a meta-analysis of recent papers on this subject and herein provide the overall efficacy and safety of PVP for treatment of BPH.

Objective

  • To assess the overall efficacy and safety of photoselective vaporization of the prostate (PVP) vs transurethral resection of the prostate (TURP) for treating patients with lower urinary tract symptoms (LUTS) secondary to benign prostate hyperplasia (BPH).

Patients and Methods

  • A systematic search of the electronic databases, including MEDLINE, Embase, Web of Science and The Cochrane Library, as well as manual bibliography searches were performed.
  • The pooled estimates of maximum flow rate (Qmax), postvoid residual (PVR), quality of life (QoL), International Prostate Symptom Score (IPSS), operation duration, blood loss, catheterization time, hospital stay, capsule perforation, transfusion, transurethral resection (TUR) syndrome, urethral stricture and reintervention were calculated.

Results

  • At the 3-month follow-up, there was no significant difference in Qmax, PVR, QoL and IPSS between the TURP and PVP groups.
  • At the 6-month follow-up, the pooled QoL favoured TURP, but there was no significant difference in the other variables between the two groups.
  • PVP was associated with less blood loss, transfusion, capsular perforation, TUR syndrome, shorter catheterization time and hospital stay, but longer operation duration and higher reintervention rate.

Conclusions

  • The efficacy of PVP was similar to that of TURP in relation to Qmax, PVR, QoL and IPSS, and it offered several advantages over TURP.
  • As a promising minimal invasive technique, PVP could be used as an alternative surgical procedure for treating BPH.
Abbreviations
HoLEP

holmium laser enucleation of the prostate

PVP

photoselective vaporization of the prostate

PVR

postvoid residual; Qmax, maximum flow rate

QoL

quality of life

RCTs

randomized controlled trials

RR

risk ratio

TUR

transurethral resection

WMD

weighted mean difference

Introduction

Benign prostate hyperplasia is one of the most common diseases affecting ageing men. It has been reported that 25–40% of men aged >50 years need medical intervention for BPH [1]. Surgery has been shown to be the most efficient treatment for patients with LUTS secondary to BPH, and among the surgical procedures TURP remains the ‘gold standard’ [2, 3]. Despite the great improvement in urinary flow rate and IPSS achieved as a result of TURP, TURP-related morbidity, such as bleeding and transurethral resection (TUR) syndrome, and mortality are of some concern [2, 4-6]. These disadvantages of TURP have encouraged people to develop new, alternative surgical procedures that might surpass TURP.

Photoselective vaporization of the prostate (PVP) is a new technique that is predominantly performed with 532-nm green laser generated by potassium titanyl phosphate or lithium triborate crystal [7, 8]. The green laser is extensively absorbed by haemoglobin and soft tissue, and subsequently reduces the risk of deeper tissue injuries [9].

Sixty-watt PVP was first introduced by Malek et al. [7] in 2000, with 2-year follow-up data showing pleasing results. Subsequently 80, 120 and 160 W systems were developed [10-14]. The advances in the 80 W system related not only to power delivered, but also to the delivery system itself, the ‘starpulse’ system delivering ‘quasi-continuous’ energy and achieving an almost seamless stream of laser energy averaging 80 W of power. Subsequent developments were the GreenLight HPS generator in 2006/7, the laser source changing from neodymium doped yttrium aluminium garnet (Nd:YAG)/potassium titanyl phosphate to lithium triborate – the latter allowing the production of up to 120 W without the need for water-cooling. The evolution continued with the development of the Greenlight XPS generator (still lithium triborate) in 2010 and, perhaps more importantly, the new MOxY laser fibre capable of dealing with the 180 W developed by the new generator.

However, the real advantages of PVP over TURP and whether PVP can replace TURP as the first-line surgical treatment still remained to be determined. The aim of the present study is to compare the efficacy and safety of PVP with those of TURP for treating patients with LUTS secondary to BPH.

Patients and Methods

A systematic search of the electronic databases, including MEDLINE, Embase, Web of Science and The Cochrane Library, was performed using the terms ‘photoselective vaporization of the prostate’, ‘PVP’, ‘transurethral resection of the prostate’ and ‘TURP’. In addition, a full manual search of the references in each relevant article was also conducted. The article language was restricted to English and Chinese. All relevant studies comparing PVP and TURP were included for further screening (Table 1).

Table 1. Searching strategies and results.
DatabaseDateSearch strategyResults
PubMedUp to Jan. 2012(‘Photoselective Vaporization of the Prostate’ OR PVP) AND (‘Transurethral Resection of the Prostate’ OR TURP)101
EmbaseUp to Jan. 2012(‘Photoselective Vaporization of the Prostate’:ab,ti OR PVP:ab,ti) AND (‘Transurethral Resection of the Prostate’:ab,ti OR TURP:ab,ti)143
Web of ScienceUp to Jan. 2012TS = (‘Photoselective Vaporization of the Prostate’ OR PVP) AND TS = (‘Transurethral Resection of the Prostate’ OR TURP)84
Cochrane LibraryUp to Jan. 2012(‘Photoselective Vaporization of the Prostate’ OR PVP) AND (‘Transurethral Resection of the Prostate’ OR TURP)9

Inclusion and exclusion criteria were defined before the literature search. Studies meeting the following criteria were included: studies comparing the efficacy and safety of PVP with those of TURP; patients with LUTS due to BPH; maximum flow rate (Qmax) ≤15 mL/s; and IPSS >7. Exclusion criteria were defined as follows: patients with neurogenic bladder; those with suspected or diagnosed prostate cancer.

Two independent reviewers completed this procedure and all disagreements were resolved by consensus.

The methodological quality of randomized controlled trials (RCTs) was scored with the Jadad composite scale, which is a five-point scale [15, 16]. A score ≤2 indicates a low quality while a score ≥3 indicates a high quality [16, 17]. The methodological quality of non-RCTs was assessed with the Newcastle–Ottawa Scale, which is a ‘star system’ containing eight items, categorized into three broad perspectives: the selection of the study groups; the comparability of the groups; and the ascertainment of the outcome [18]. The Newcastle–Ottawa Scale ranges between zero and nine stars. This procedure was independently performed by two reviewers, and disagreements were resolved by consensus.

Two reviewers carried out an independent view of the full text of all included studies. The following data were extracted from each eligible study: authors, journal and publication year, number of patients, Qmax, postvoid residual (PVR), quality of life (QoL), IPSS, operation duration, blood loss, catheterization time, hospital stay, capsule perforation, transfusion, TUR syndrome, urethral stricture and reintervention.

A meta-analysis comparing the efficacy and safety of PVP with those of TURP was performed. The risk ratio (RR) and mean or standardized mean difference was used for binary outcomes and continuous variables, respectively. Pooled estimates were calculated with a fixed-effect model (Mantel–Haenszel method) [19] if no significant heterogeneity was present; otherwise, a random-effect model (DerSimonian–Laird method) [20] was applied. The pooled effects were determined by Z-test and P < 0.05 was considered to indicate statistical significance. The Cochrane chi-squared test and inconsistency (I2) were used to assess the heterogeneity among studies. P < 0.10 was considered to indicate the present of heterogeneity, while I2 < 50% was considered to indicate acceptable heterogeneity. Data analysis was performed with Review Manager (RevMan 5.1, Cochrane Collaboration, Oxford, UK).

Results

After an initial search in the databases, 223 potential studies were identified for further retrieval. Finally nine studies [8, 14, 21-27] were enrolled in the meta-analysis (Fig. 1). The baseline characteristics of included studies are shown in Table 2.

Figure 1.

Flowchart showing the selection of studies for meta-analysis.

Table 2. Baseline characteristics of included studies.
StudiesTreatmentsNo. of patientsLaser powerQmax (mL/s)PVR (mL)QoLIPSSPublication type
Bachmann et al. [21]TURP37Not mentioned6.9 ± 2.2120.7 ± 49.03.4 ± 1.617.3 ± 6.3Non-RCT
PVP646.9 ± 1.9146.1 ± 106.93.3 ± 1.718.1 ± 5.9
Horasanli et al. [22]TURP3780W9.2 ± 5.6176.9 ± 45.320.2 ± 6.8RCT
PVP398.6 ± 5.2183.0 ± 50.118.9 ± 5.1
Tasci et al. [23]TURP41Not mentioned6.5 ± 1.8110.7 ± 59.83.5 ± 0.622.6 ± 3.9Non-RCT
PVP406.2 ± 2.2116.5 ± 60.53.6 ± 0.722.3 ± 5.6
Tugcu et al. [24]TURP98Not mentioned7.2 ± 1.7100.3 ± 57.13.4 ± 0.517.7 ± 3.5Non-RCT
PVP1126.9 ± 1.9107.9 ± 63.03.4 ± 0.617.9 ± 4.9
Al-Ansari et al. [8]TURP60120W6.4 ± 257 ± 2127.9 ± 2.7RCT
PVP606.9 ± 2.253.2 ± 2527.2 ± 2.3
Bouchier-Hayes et al. [25]TURP5980W8.86 ± 2.99113 ± 113.75.08 ± 0.9425.41 ± 5.72RCT
PVP608.81 ± 2.55129.2 ± 155.74.74 ± 1.2325.28 ± 5.93
Capitán et al. [26]TURP50120W3.88 ± 2.714.14 ± 1.0623.52 ± 4.38RCT
PVP508.03 ± 3.144.52 ± 0.2723.74 ± 5.24
Chen et al. [14]TURP51160W6.8 ± 2.3102.2 ± 70.121.8 ± 7.3Non-RCT
PVP576.9 ± 4.093.7 ± 79.719.7 ± 6.0
Lukacs et al. [27]TURP70120W7.76 ± 2.6475 (28–126)75 (65–85)20 (15–23)RCT
PVP607.79 ± 2.7589.5 (30–158.5)70 (68–80)22 (17–26)

Tables 3 and 4 show the results of quality assessments of RCTs and non-RCTs, respectively. For RCTs, the nature of the study made blinding impossible, and thus four studies got a score of 3, while one study got a score of 2 because of the lack of description of randomization. For non-RCTs, all study were of a high quality with a score of nine stars.

Table 3. The Jadad scale for quality assessment of RCTs.
 Horasanli et al. [22]Al-Ansari et al. [8]Bouchier-Hayes et al. [25]Capitán et al. [26]Lukacs et al. [27]
Was the study described as randomized (e.g. using the words randomly, random and randomization)?11111
Was the method of randomization described and appropriate (e.g. table of random numbers, computer-generated)?01111
Was the study described as double-blind?00000
Was the method of blinding described and appropriate (e.g. identical placebo, active placebo, dummy)?00000
Was there a description of withdrawals and dropouts?11111
Total23333
Table 4. The Newcastle-Ottawa Scale for quality assessment of non-randomized studies.
StudiesSelectionComparabilityOutcomeTotal score
Representativeness of the exposed cohortSelection of the non-exposed cohortAscertainment of exposureOutcome of interest was not present at start of studyBased on the design or analysisAssessment of outcomeFollow-up long enough for outcomes to occurAdequacy of follow-up of cohorts
Bachmann et al. [21]111121119
Tasci et al. [23]111121119
Tugcu et al. [24]111121119
Chen et al. [14]111121119

At baseline, the Qmax, PVR, QoL and IPSS of patients in both the TURP and PVP groups were similar (Fig. 2). There were no significant differences in Qmax, PVR, QoL and IPSS between the groups at 3 months after the operation (Qmax: weighted mean difference [WMD] = 0.25, 95%CI: −1.40–1.90, P = 0.76; PVR: WMD = −7.73, 95%CI: −21.99–6.53, P = 0.29; QoL: WMD = −0.01, 95%CI: −0.09–0.07, P = 0.81; IPSS: WMD = −0.30, 95%CI: −0.93–0.33, P = 0.35) (Fig. 3). At 6 months after the operation, the pooled QoLs were significantly different (WMD = 0.10, 95%CI: 0.13–0.16, P = 0.003), while the other variables showed no significant difference (Qmax: WMD = 0.40, 95%CI: −0.87–1.67, P = 0.54; PVR: WMD = −3.05, 95%CI: −9.74–3.65, P = 0.37; IPSS: WMD = −0.36, 95%CI: −1.01–0.28, P = 0.27) (Fig. 4). However, the heterogeneity among studies was clear.

Figure 2.

Pooled estimates of baseline Qmax, PVR, QoL and IPSS.

Figure 3.

Pooled estimates of Qmax, PVR, QoL, IPSS at 3 months follow-up.

Figure 4.

Pooled estimates of Qmax, PVR, QoL, IPSS at 6 months follow-up.

The significant differences in blood loss (decrease of haemoglobin), catheterization time and hospital stay between groups (blood loss: WMD = 1.33, 95%CI: 0.61–2.05, P = 0.001; catheterization time: weighted standardized mean difference [WSMD] = 2.95, 95%CI: 1.78–4.11, P < 0.001; hospital stay: WSMD = 2.91, 95%CI: 1.80–4.01, P < 0.001) suggest advantages of PVP over TURP (Fig. 5). However, PVP requires a longer operation duration than TURP (WMD = −17.94, 95%CI: −30.29–5.59, P = 0.004) (Fig. 5). In addition, there was great heterogeneity among the studies.

Figure 5.

Pooled estimates of perioperative variables.

Transfusion, capsular perforation and TUR syndrome were significantly less frequent in the PVP group than in the TURP group (transfusion: RR = 5.88, 95%CI: 1.92–18.3, P = 0.002; capsular perforation: RR = 9.28, 95%CI: 2.79–30.88, P = 0.001; TUR syndrome: RR = 5.31, 95%CI: 1.18–23.94, P = 0.003) (Fig. 6). Both groups had a similar urethral stricture rate (RR = 1.77, 95%CI: 0.94–3.33, P = 0.08) (Fig. 6). However, patients in the PVP group had a higher reintervention rate than those in the TURP group (RR = 0.24, 95%CI: 0.10–0.59, P = 0.002) (Fig. 6). There was no heterogeneity.

Figure 6.

Pooled estimates of adverse events. M-H, Mantel–Haenszel method.

Discussion

Transurethral resection of the prostate is extremely effective in treating LUTS secondary to BPH and has been regarded as the ‘gold standard’ for decades. However, there has been no significant decrease in TURP-related morbidity since Nesbit popularized it in 1943 [22]. Since then, the search for alternative surgical procedures with similar efficacy but minimal complications has never ceased. Holmium laser enucleation of the prostate (HoLEP) is one of the most promising protocols. A meta-analysis comparing HoLEP and TURP showed identical efficacy but lower morbidity for treating BPH [28]. However, HoLEP is technically demanding, potentially dangerous in inexperienced urologists and requires extended training [25]. PVP is another promising technique, and requires a shorter mentorship period [25, 29]. Many studies have shown encouraging efficacy and safety [8, 14, 21-27, 29, 30]. In the present study we have shown the overall efficacy and safety of PVP compared with TURP.

Larger prostate size (80 mL or larger) is a relative contraindication for TURP, and is likely to increase the morbidity risk. However, this is not the case with PVP [23, 31, 32]. Many studies have shown the safety of PVP for patients on anticoagulants [24, 31, 33, 34], which is a strict exclusion criterion for TURP. The pooled estimates of our meta-analysis gave similar results for PVP and TURP on both subjective (IPSS, QoL) and objective variables (Qmax, PVR). Although at the 6-month follow-up, the QoL was slightly higher in the TURP group, reaching a statistically significant difference, it was of no clinical significant difference. At 12 months follow-up, the QoL of both groups was equal (data not shown).

The operation duration of PVP was significantly longer than that of TURP. This might be because the surgeons were not well versed in it, and also because of insufficient energy supply from the laser system. Chen et al. [14] argued that a higher-power laser system would improve the vaporization efficiency and reduce the operation duration. However, despite the longer procedure time, with the use of 0.9% saline as the irrigation fluid in PVP, the incidence of TUR syndrome, which is a severe complication of TURP, was significantly lower than in the TURP group. In fact, in present meta-analysis, none of the 203 patients in PVP group developed TUR syndrome.

There was less blood loss and lower transfusion rate in the PVP group than in the TURP group. This can be explained by the nature of the green light laser, which achieved an optimal coagulation depth of up to 3 mm in prostate tissue [35, 36]. In the present meta-analysis, there was no capsular perforation (0/372) in the PVP group, whereas it occurred in 22 of 324 patients in the TURP group. This is another potential advantage of PVP over TURP. It was also noted that the catheterization time among the PVP group was significantly shorter than among the TURP group, resulting in earlier mobilization, shorter hospital stay and lower hospitalization costs.

Some authors have argued that the preservation of sexual function is another advantage of PVP over TURP. Capitan et al. [26] showed a significantly lower retrograde ejaculation rate among the PVP group than among the TURP group. Malek et al. [10] believed that some muscle fibres could regenerate after PVP. Although Lukacs et al. [27] found no significant difference in erectile and ejaculatory disorders between the two groups after operation, there was a trend for improvement of erection, ejaculation and sexual satisfaction in the PVP group. However, in the present study, we did not carry out a meta-analysis of sexual function between the two groups.

One disadvantage of PVP has to do with the reintervention rate. In the present meta-analysis, the rate of reintervention was significantly higher in the PVP group than in the TURP group. Although the endpoints of both TURP and PVP are visible cavities, it has been reported that TURP has the advantage over PVP of a greater reduction in prostatic volume [14, 21, 22]. Furthermore, the retention of the coagulated, necrotic tissue after vaporization could be another reason for reintervention [22]. Another important drawback of PVP is the absence of tissue obtained during the operation. Thus, an intensive examination of the patient (DRE, PSA level or even prostate biopsy, if necessary) must be carried out before the operation to exclude the possibility of prostate cancer. However, with the development of green light technology, further improvements could become apparent, and PVP could be more efficient and safe in treating BPH.

There are several limitations in the present meta-analysis. First, for non-RCTs were included because of the insufficient comparative RCTs. Secondly, the follow-up was not long enough, only one study [25] was carried out with a 12-month follow-up and two [23, 24] with a 24-month follow-up. Thus the long-term efficacy and safety of PVP cannot be evaluated. Thirdly, for some variables, there was great heterogeneity among the studies. As the generators have improved significantly over time, different systems were used for different studies, and the HPS generator represented a huge step forwards in terms of speed and efficiency of tissue vaporization, and therefore removal, compared with the 80 W system. This might contribute to the heterogeneity. Although random-effect model was applied in these items, there might be some influences on the efficiency of our meta-analysis.

In conclusion, PVP had a similar efficacy to TURP in terms of Qmax, PVR, QoL and IPSS and offered several advantages over TURP in terms of blood loss, transfusion, capsular perforation, TUR syndrome, catheterization time and hospital stay, while TURP was superior in terms of operation duration and reintervention rate. However, there is still currently not enough evidence to justify replacing TURP. As a promising minimal invasive technique, PVP could be used as an alternative surgical procedure for treating BPH.

Conflict of Interest

None declared.

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