Transurethral resection of the prostate (TURP) has historically been the gold-standard treatment for lower urinary tract symptoms (LUTS) associated with benign prostatic enlargement (BPE), but advances over the last 2 decades have led to the introduction of less-invasive approaches to treatment, including the use of laser therapy. One of the main forms of this type of therapy involves the GreenLight laser. The original laser used was a potassium-titanyl phosphate laser which produces a green visible light beam at 532 nm that is selectively absorbed within the tissue by haemoglobin and not by water, and has a short penetration depth of 0.8 mm. The laser acts through photoselective vaporization of the prostate (PVP). A high-powered 120 W (GreenLight HPS) laser was subsequently developed and finally the GreenLight 180 W xcelerated Performance System (XPS) laser involving the MoXy fibre. This laser has a 50% increase in both power and laser beam area, maintaining a similar energy density at the laser spot and thus a similar safety profile as the former 120 W system. The purpose of this article is to review the clinical evidence that establishes that GreenLight laser therapy is a principle treatment for LUTS associated with BPE.
A number of generations of the GreenLight laser have been developed with an increase in power with each reiteration.
80 W GreenLight laser
In 2008, Ruszat et al. reported the long-term outcome with the 80 W GreenLight laser in 500 patients, of whom 45% were receiving anticoagulants and had a mean (SD) prostate volume of 56.1 (25.3) ml. Improvements in the International Prostate Symptom Score (IPSS) and maximum flow rate (Qmax) were reported at first follow-up at 1 month. At 5 years’ follow-up, mean (SD) IPSS was reduced from 18.3 (6.5) to 7.6 (5.6) and Qmax from 8.4 (5.0) to 17.5 (7.5) ml/s, with no significant difference reported between prostates of size less than 40 ml and those greater than 80 ml. The primary postoperative complication was dysuria (24.3%), followed by haematuria (8.7%); long-term complications included urethral and bladder neck strictures, which were observed in 4.4 and 3.6% of the patients, respectively. Retreatment rate was 6.8%. This study confirmed the efficacy and safety of the 80 W laser in the short and long term.
120 W GreenLight laser
Outcome with the 120 W High Performance System (HPS) laser has been compared with TURP in a number of studies. Xue et al. reported 3-year efficacy and safety results in 100 men treated with laser and 100 treated with TURP. The degree of decrease in IPSS, increase in the quality of life (QoL), increase in Qmax and decrease in postvoid residual urine (PVR) were comparable in both groups at all time points of follow-up (Fig. 1). In terms of intraoperative complications, significantly more blood transfusions were required in the TURP group (4 vs. 0%; P < 0.05) and capsular perforations were also more common (5 vs. 0%; P < 0.05). The majority of postoperative complications occurred at a similar rate in both groups with some exceptions. Macroscopic haematuria at day 2 was more common in the TURP group (39 vs. 8%; P < 0.05), as was retrograde ejaculation during follow-up (60.5 and 30.6%; P < 0.05). Whelan et al. also studied the outcome following PVP (n = 140) and TURP (n = 24), and reported no statistically significant difference between groups at 6 months in terms of IPSS, Qmax and erectile function; PVR reductions were significantly greater in the PVP group (P = 0.018). There was no significant difference in the complications between the two groups. Other comparative studies of the 120 W GreenLight laser and TURP also report favourable findings for PVP [4–8].
The 120 W GreenLight laser has been evaluated in special patient groups, including those in retention, on anticoagulants and with large prostates (≥80 ml) . Woo et al. reported on a series of 305 consecutively treated patients and found that at a mean (SD) follow-up of 4.2 (4.5) months in terms of the primary efficacy outcome parameters, anticoagulant use had no significant effect on changes from the baseline values. For patients in retention, the only significant difference between groups was change in Qmax, which was greater in patients not in retention (P < 0.001). Prostate volume reduction was significantly greater in patients with prostates of size at least 80 ml (P < 0.001). A low rate of complications was recorded in all groups, confirming the safety and efficacy of the 120 W laser in a broad spectrum of patients.
PVP has been shown to have a low impact on sexual function in the long-term follow-up. In one study, 39 men with an International Index of Erectile Function (IIEF)-5 score at least 19 (normal erectile function) and 110 men with a score less than 19 (reduced erectile function) were treated with the 120 W GreenLight laser by a single surgeon . At 2 years after procedure, no significant change in IIEF was reported in the group overall; however, for patients with a baseline IIEF score at least 19, the reduction was significant (P = 0.0029).
180 W GreenLight laser
Bachmann et al. made one of the first reports with the 180 W XPS laser in 2011, reporting the outcome in 201 men at a mean of 5.8 months’ follow-up. Of the patient group, 25% had prostates of size at least 80 ml. Statistically significant improvements were noted in all key parameters from 1 month postoperatively and these were maintained up to 6 months. The prevalence of perioperative complications was low.
The objectives of increasing the GreenLight laser power from 120 to 180 W was to increase the vaporization rate and speed, and allow the treatment of larger prostates. Ben-Zvi et al. compared the safety and efficacy of the two lasers in a series of 200 patients treated at a single centre. Operating parameters and postoperative outcomes are shown in Table 1. Operating and laser times as well as the energy expended were shorter with the 180 W laser, as was the number of fibres used and hospitalization period. No significant differences were reported in the 30-day postoperative complications with the exception of urinary retention, which was significantly higher in the 120 W laser group (16 vs. 6%; P = 0.03). Efficacy up to 6 months was comparable in the two groups with the exception of prostate-specific antigen reduction, which was significantly greater in the 180 W laser group (79 vs. 54%; P = 0.01).
One of the most important studies on the 180 W XPS laser is the Goliath Study, a randomized controlled trial comparing outcome with TURP and conducted at 29 centres in nine countries on 281 patients [13▪▪]. This study, one of the most rigorously performed on any surgical procedure in urology, provided definitive evidence that the GreenLight laser is noninferior to TURP in terms of improvements in IPSS, Qmax, PVR and prostate volume. Complication rate was also similar between the groups. Length of catheterization and hospital stay were superior with the XPS laser, whereas early reintervention rate within 30 days was three times higher with TURP; the rate at 6 months was similar in the two groups.
Economic comparison of GreenLight laser therapy to the other treatment options for men with LUTS associated with BPE are difficult because of the different reimbursement systems in different countries. One Australian study showed that PVP was less expensive than TURP (AU$3368 vs. AU$4291), primarily because of the shorter hospital stay, length of catheterization and lower complication rates . A Canadian study also reported that PVP was less costly than TURP ($3891 vs. $4863; P < 0.001) . The same study compared PVP and TURP in terms of quality-adjusted life years (QALYs) at 6 months and found that the two treatments had similar QALYs. In contrast, a Swiss study reported comparable cost between TURP and PVP .
Future directions: enucleation
Recent refinements in the surgical technique developed in Madrid, Spain, that allow the localization of the prostatic surgical capsule, have been derived in a stepwise progressive learning pathway. A GreenLight user can move on from the traditional PVP technique to ‘anatomic PVP’ that ensures that the surgical capsule is reached during vaporization. The next step is to perform ‘hybrid vapo-enucleation technique’ and finally an en-bloc enucleation technique involving mechanical dissection of the adenoma in one piece for the complete removal of the transition zone of the prostate . The initial step involves a circumferential apical incision to localize the prostate capsule, followed by enucleation of the transition zone in a single bloc with morcellation of the tissue after it has been transferred to the bladder. This process will allow the treatment of even greater-sized prostates than those previously treated. Clinical outcome data with this new technique are expected to be published in the near future and are expected to enhance the established efficacy of the GreenLight laser observed in the Goliath Study with more complete removal of the adenomatous tissue.
There have been numerous studies conducted on the three generations of the GreenLight laser. Each has shown positive outcome for patients with LUTS associated with BPE and, importantly, equivalence in efficacy and safety to TURP. Exciting future developments with the GreenLight laser involve an enucleation technique that will allow even greater-sized prostates to be treated. Truly, GreenLight laser therapy has come of age!
The author would like to thank MedSciMedia for the editorial support.
Conflicts of interest
F.G.-S. has acted as a paid speaker at AMS sponsored symposia and has acted as a consultant at AMS Advisory Board meetings.
REFERENCES AND RECOMMENDED READING
Papers of particular interest, published within the annual period of review, have been highlighted as:
- ▪ of special interest
- ▪▪ of outstanding interest
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A landmark study establishing equivalence between the high-powered GreenLight laser and TURP.
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