Changing Paradigms: Green Laser Vaporization for Prostates over 80 mL: A Comparative Study

Abstract

Introduction and Objectives:

Benign prostatic enlargement (BPE) and big prostates are common. Photovaporization of the prostate (PVP) with Greenlight™ laser 180 W XPS is considered a reliable therapy for prostates <80 mL and an alternative for the treatment of bigger ones in selected cases. The aim of this study is to evaluate efficacy, safety, and functional outcomes of PVP among patients with prostates over and under 80 mL.

Materials and Methods:

After protocol approbation by our Institutional Ethics Committee, a cohort of 840 patients with BPE who underwent PVP with Greenlight laser between 2012 and 2019 in a single center was evaluated. Groups were stratified according to prostate volume, to less and greater than 80 mL (Groups 1 and 2, respectively). The primary outcomes were efficacy [prostate-specific antigen (PSA) drop, improvement of International Prostatic Symptom Score (IPSS), and quality of life] and variables regarding safety of the procedure. Peri- and postoperative outcomes were analyzed. Complications were assessed according to Clavien–Dindo classification. Overall patient satisfaction was evaluated with visual analog scale.

Results:

Preoperative variables showed no statistical difference among groups. Mean follow-up was 47 [interquartile range; IQR = 26–70] months. Longer operative time and a higher energy use was seen in bigger prostates (p < 0.001). Efficacy was similar between groups, with a reduction of ≥4 points in IPSS score in 83.1% and 89.5% in Groups 1 and 2 (p = 0.053), PSA drop was 1 ± 2.6 and 1.7 ± 4.7 (p = 0.32). Group 2 had a higher conversion rate (0.3% vs 4.9%, p < 0.001) and higher blood transfusion rate (0% vs 2.4%, p < 0.001). There were no differences in hospital stay, catheterization time, urethral stricture, or re-treatment rates.

Conclusions:

GreenLight PVP is a safe and effective procedure in prostates ≥80 mL. It shows the same advantages demonstrated for those under that volume, particularly short hospital stay and catheterization time. Surgeon's experience is important to avoid complications, such as conversion and transfusion. PVP should be considered a first-line alternative for the treatment of bigger prostates.

Introduction

Benign prostatic enlargement (BPE) causes lower urinary tract symptoms (LUTS) and it is associated with a reduction in quality of life (QoL).^1,2 The prevalence increases with aging, with rates up to 50% at the age of 50 and 88% in the eighth decade of life.² Because of the increase in life expectancy and the chronic use of alpha-blockers, patients with bigger prostates are now common.

Historically, transurethral resection of the prostate (TURP) was the first-line surgical treatment for BPE in prostates of 30 to 80 mL.^3
–5 However, this technique has been associated with perioperative morbidities such as TURP syndrome and bleeding.^3
–5

Modern laser technologies such as Greenlight™ Laser have reduced morbidity, maintaining the same efficacy.^3
–5 Experience with the 80 and 120 W laser allowed this technique to be considered as a first-line option such as TURP in several guidelines.^1,2

Open prostatectomy (OP) is the standard of treatment for prostates of >80 mL. Recently laser enucleation techniques have become an alternative, considering that OP is highly effective but is the most invasive treatment for BPE.²

In 2010, the GreenLight Laser 180 W XPS appears showing an enhanced vaporization rate.⁶ Histopathologic outcomes caused by laser-tissue interaction remain unchanged compared with 80 to 120 W.³ Its safety profile allowed urologists over the world to consider it an alternative in patients with prostates >80 mL.^2,3 However, it is not globally accepted for large prostates. The American Urological Association (AUA) guideline for the management of lower tract symptoms considers Green laser as an alternative in average size prostates and advocates Holmium laser enucleation of the prostate, Thulium laser enucleation of the prostate, and simple prostatectomy for large prostates.¹

In this single-center study, we evaluate and compare the efficacy, safety, and functional outcomes of photovaporization of the prostate (PVP) with GreenLight Laser 180W XPS between patients with prostates bigger and smaller than 80 mL.

Materials and Methods

A cohort study was conducted. All patients with LUTS secondary to BPE, who underwent PVP with Greenlight Laser 180W XPS in Hospital Universitario Fundación Santa Fe de Bogotá, Bogotá DC, Colombia, between 2012 and 2019 were included, and their medical records reviewed. Only patients with insufficient data were excluded.

Patients with prostates >80 mL (study group) included as Group 2 and those with prostates under that volume were included in Group 1 (control group).

The procedure was usually performed under general anesthesia. A 23F cystoscope was used as a visual field with a continuous flow of Ringer's Lactate. Technique was vaporization in all cases, and only one fiber was used. The procedure initiates with low energy (80 W) in the bladder neck and apex and increases until it reaches 180 W in lateral lobes. Vaporization started according to the ease of access to the ideal resection distance. Bladder neck in the presence of a middle lobe was treated with special care. Finally, the distal portion was vaporized, being cautious with resection's lower limit (verumontanum). A 20 to 24F Foley catheter of two or three ways was used according to surgeon's preference. Postoperative irrigation was randomly used only in case of gross hematuria; urinary catheter was removed in the first postoperative morning in patients without warning signs (particularly hematuria), despite the hour surgery was performed. Patients were discharged after spontaneous voiding.

The first follow-up was usually scheduled after 1 week. prostate-specific antigen (PSA), International Prostatic Symptom Score (IPSS), QoL, Sexual Health Inventory for Men, and visual analog scale (VAS) were evaluated during further visits, usually performed during the first 3 months after the procedure. Follow-up continued according to surgeon's preference. Data of the last visit were recorded. When not available, telephonic or e-mail contact was established, and IPPS and QoL questionnaires were completed.

Regarding functional outcomes an improvement ≥4 points in the IPSS score was, and a decrease ≥1 point in QoL question were defined as significant. PSA drop was evaluated as an absolute decrease in ng/mL, VAS corresponds to a single question requested after the procedure, asking for satisfaction with the postoperative result. The preoperative, perioperative, and immediate postoperative information was taken from the retrospective review of the medical and surgical records.

Statistical software SPSS 24.0 (IBM, 2016) was used, a descriptive analysis was carried out reporting frequencies for discrete variables, and measures of central tendency and dispersion for continuous variables. Normality tests were developed and Mann–Whitney and Student's t-test were used according to the distribution of the continuous variables. Likewise, chi-square test was used to compare frequencies. A p-value <0.05 was considered significant.

Results

A total of 840 patients were analyzed. Median follow-up was 47 months [interquartile range; IQR = 26–70]. The mean age in groups 1 and 2 were 64.6 ± 8.8 and 65.4 ± 8.8, respectively (alpha-blockers +5-alpha-reductase inhibitors), American Society of Anesthesiology (ASA) classification system of physical status before the procedure and urodynamic parameters as shown in Table 1.

Table 1.

Preoperative Characteristics and Urodynamic Parameters

	Group 1 prostate <80 mL (n = 381)	Group 2 prostate ≥80 mL (n = 206)	p
Preoperative characteristics
Age (years)^a	64.6 ± 8.8	65.4 ± 8.8	0.34
BMI (kg/m²)^a	25.7 ± 3	25.8 ± 3	0.58
PSA(ng/mL)^b	1.8 (1.2–3.9)	2.4 (1.5–4.6)	<0.001
IPSS^b	16 (12–25)	17 (12–23)	0.12
QoL^a	4 (4–5)	4 (3–6)	0.07
Prostate volume^b (mL)	50 (37–65)	97.5 (89–115)	<0.001
History of anticoagulation^c	22 (5.8)	13 (6.3)	0.67
History of urinary retention^c	96 (26)	90 (44.3)	<0.001
History of urinary stricture^c	40 (10.5)	11 (5.3)	0.02
Use of alpha-blocker +5-alpha-reductase inhibitors^c	173 (50.3)	130 (67)	0.9
ASA			0.97
1–2	289 (76.2)	156 (76.1)
3–4	89 (23.5)	49 (23.9)
Urodynamic parameters
Qmax (mL)^b	9.3 (6–14)	9 (4.7–13.5)	0.07
Detrusor hyperactivity^c	180 (62.1)	82 (61.2)	0.77
Impaired detrusor contractility^c	133 (47)	49 (37.1)	0.05
PVR (mL)^b	200 (100–300)	240 (150–500)	0.07
BOOI^b	50 (36–61)	55 (39.2–75)	<0.001
BCI^b	99 (80.3–120)	112.5 (86–133.7)	<0.001

Reported as mean ± standard deviation.

Reported as median and interquartile ranges.

Reported as frequencies in percentages.

ASA = American Society of Anesthesiology; BCI = bladder contractility index; BMI = body mass index; BOOI = bladder outlet obstruction index; IPSS = International Prostatic Symptom Score; PSA = prostate-specific antigen; PVR = postvoid residual volume; QoL = quality of life.

Intraoperative characteristics are summarized in Table 2. As expected, mean operative time and energy applied was higher in Group 2; however, the energy density in Group 2 was lower than in Group 1 5.3 [IQR 3.5–6.8] vs 3.8 [IQR 2.6–4.9]. Bleeding control with Bugbee and conversion rate were higher for Group 2 (3.9% vs 11.7%, p < 0.001) and (0.3% vs 4.9%, p < 0.001), respectively. Three (n = 3) conversions were caused by technical failures with laser (fiber fracture and fiber failure) and six (n = 6) were caused by bleeding. Catheterization time and hospital stay were similar for both groups. Failure to void was more common in Group 1: 1 (10%) vs 8.7% (p = 0.25) in Group 2.

Table 2.

Intra- and Postoperative Characteristics, and Functional Outcomes

	Group 1 prostate <80 mL (n = 381)	Group 2 prostate >80 mL (n = 206)	p
Intraoperative characteristics
Surgery time (minutes)^a	60 (50–95)	75 (60–115)	<0.001
Time of applied laser (minutes)^a	35 (25–42)	50 (37–58)	<0.001
Energy applied (kJ)^a	247 (162–330)	357 (258–481)	<0.001
Time of laser/surgery^a	0.56 (0.41–0.69)	0.6 (0.5–0.7)	<0.001
Energy density (kJ/mL)^a	5.3 (3.5–6.8)	3.8 (2.6–4.9)	<0.001
Intraoperative bleeding control^b	15 (3.9)	24 (11.7)	<0.001
Conversion rate^b	1 (0.3)	8 (4)	<0.001
Postoperative characteristics
Length of stay (hours)^a	22.3 (19.5–27.3)	21.5 (18.4–26.2)	0.09
Time of indwelling catheter (hours)^a	17.7 (15–21.5)	17.2 (14.1–22.5)	0.15
Reintervention caused by LUTS^b	7 (2.2)	4 (2.3)	0.95
Functional outcomes
Drop in PSA^c	1 ± 2.6	1.7 ± 4.7	0.32
Improvement of IPSS^c	103 (83.2)	68 (89.5)	0.053
Improvement of QoL^c	71 (86.6)	−2.2 ± 1.9	0.24
VAS satisfaction^a	8 (8–9)	9 (8–10)	0.48

Reported as median and interquartile ranges.

Reported as frequencies in percentages

Reported as mean ± standard deviation.

IPSS = International Prostatic Symptom Score; LUTS = lower urinary tract symptoms; VAS = visual analog scale.

All functional outcomes significantly improved from the baseline after the procedure in both groups. The mean drop in PSA for Group 1 was 1 ng/mL vs 1.7 ng/mL in Group 2. 89.5% of patients in Group 2 vs 83.1% in Group 1 met the criteria for significant reduction in IPSS. A percentage decrease in IPSS of 80% [IQR 50–100] was found. QoL improved in both groups. Although improvement was slightly higher in Group 1, these data showed no statistical significance. VAS satisfaction after the procedure was 8 for both groups (Table 2).

No significant difference was found in the comparative groups of complications; however, there was a significant difference in conversion and transfusion rates (2.4% vs 0%, p < 0.001) (Table 2). Reintervention caused by LUTS was extremely unusual and was seen on only 2% of the patients for both groups with a maximum follow-up of 70 months. Complications discriminated by medical condition are found in Table 3.

Table 3.

Complications

	Group 1 prostate <80 mL (n = 381)	Group 2 prostate >80 mL (n = 206)	p
Clavien–Dindo, n (%)
I	9 (1.6)	11 (1.9)	0.26
II	77 (13.6)	44 (7.7)	0.12
IIIa	3 (0.5)	0 (0)	0.67
IIIb	4 (0.7)	0 (0)	0.43
IVa	0 (0)	2 (0.4)	0.72
IVb	0 (0)	0 (0)	—
V	0 (0)	0 (0)	—
Type of complication, n (%)
Bleeding	4 (1.3)	4 (2.3)	0.15
Bleeding in need of transfusion	1 (0.3)	5 (3)	<0.001
Nausea and vomiting	4 (1.3)	4 (2.3)	0.63
Dyspnea of unknown origin	1 (0.3)	0 (0)	0.32
Hypertensive crisis	0 (0)	2 (1.2)	0.53
Postoperative atrial fibrillation	0 (0)	1 (0.6)	0.24
Severe desaturation	0 (0)	1 (0.6)	0.48
Acute urinary retention	38 (10)	18 (8.7)	0.54
Acute kidney failure	1 (0.3)	0 (0)	0.62
Oliguria	1 (0.3)	0 (0)	0.65
Urinary tract infection	40 (10.5)	25 (12.1)	0.17
Extravasation in prevesical space	1 (0.3)	0 (0)	0.19
Extravasation	0 (0)	1 (0.6)	0.14
Peritoneal extravasation	1 (0.3)	0 (0)	0.56
Suprapubic extravasation	1 (0.3)	0 (0)	0.52
Fever (bibasal atelectasis)	0 (0)	1 (0.6)	0.68

Discussion

GreenLight laser vaporization of the prostate has proven to be a safe an effective method for the treatment of LUTS secondary to BPH in average size prostates. Early after its emergence with the 80 and 120-W consoles, studies comparing the results with what was considered the gold standard, conventional TURP, showed no inferiority regarding effectiveness, and a better safety profile favoring PVP. A lower transfusion rate (particularly in patients under anticoagulation or antiaggregating therapies), less reabsorption syndrome and even a reduction in urethral strictures was noted.⁷

Years later, the 180-W console appeared, and the fiber was improved. Studies demonstrated that the higher potency showed enhanced rate and speed of vaporization, whereas tissue interaction remained similar to the 120-W laser and fibrosis was negligible. The Moxy fiber came with a 50% increase in the vaporization area, an active cooling system that reduced its degradation, a fiber life system that starts an alarm when exposed to extreme heat, and a 650 kJ capacity.⁶

Its clinical use was assessed in the Goliath Study⁸ with a 2-year follow-up, noninferiority regarding IPSS, Q-max, and complication rate when compared with TURP was demonstrated. These advances in technology and the rising experience with the technique have allowed surgeons to evaluate its performance in patients that represent a greater surgical challenge such as severely ill or anticoagulated individuals and those with high-volume prostates, who are poor candidates for TURP or OP.

In this study, we evaluated safety and efficacy issues in prostates >80 mL. Aware of the known effectiveness is smaller prostates, we decided to use this group as a control. Patients with bigger prostates were found to be older than controls, had higher PSA, received alpha-blockers and combined therapy more frequently, had more history of urinary retention, and had higher bladder outlet obstruction index and bladder contractility index. Surprisingly no important difference was seen regarding IPSS or QoL. Similarly, Campobasso and associates⁹ and Hueber and associates¹⁰ reported that patients with bigger prostates were older and had higher PSA values. In Campobasso's series, a higher rate of urinary retention was also seen. In contrast, Hueber did find patients to have higher scores on IPSS and QoL. No difference was found between use of anticoagulants or antiplatelet medication between groups, or in ASA scores in the three series.

Regarding perioperative performance, as expected, operative and lasing time were higher in the study group. Hueber and colleagues,¹⁰ when comparing prostates under and over 80 mL, found 45 minutes vs 80 minutes of surgery time and 24 minutes vs 45 minutes in lasing time. In our study we found 35 minutes vs 50 minutes in lasing time. When comparing the total energy use, most series with high-volume prostates report values ranging from 370 to 467 kJ. Altay and coworkers¹¹ in a study with 68 patients and an average prostatic volume of 104 mL report 398 kJ, whereas Meskawi and associates¹² in 438 patients with average prostate volume of 135 used 467 kJ. Energy density ranges in different publications from 3.2 to 4.1 kJ/mL, in large prostates, but surprisingly, it is lower than reported for smaller prostates. In our study we used 5.3 kJ/mL in small prostates, and 3.8 in big ones. Hueber used 3.8 and 3.25, and Campobasso 4.1 and 3.3, respectively. These changes might be explained by a more liberal use of energy within smaller glands. We used one fiber in all our patients. Some authors report the use of up to three fibers. The reasons are not clearly explained.

Mean hospital stay ranges from 1 to 2 days in most series, and catheterization time almost never exceeds 24 hours. Most of the patients can void on the first attempt. Failure to void happens in 5% to 10% of the patients, but almost 100% can do it after 1 week. In our study we found hospitalization time of <24 hours and an average of ∼18 hours of catheterization.

Greenlight has proven to be effective in all series. A significant drop in IPSS of up to 20 points is seen after 1 year of follow-up. Meskawi and associates¹² shows a change from a baseline score of 23 to 6 and Malek and associates,⁶ Valdivieso and colleagues¹³ addresses a decrease from 21.5 to 6.3 after a 4-year follow-up. In our study, more than four points decrease in IPSS was considered clinically significant and it was achieved in 83.1% in Group 1 and 89.5% in Group 2 drop in IPSS (p < 0.053). QoL and Q-max also improved significantly. Using a VAS score, to assess satisfaction with the procedure patients in our series reported 8/10. This is comparable with Campobasso's data, when using a patient global perception of improvement score, >80% reported one to two points. PSA is frequently used as a predictor of prostate volume; Valdivieso and colleagues used PSA value as an outcome of prostate tissue removal.¹⁴ PSA drop in our study was 1 ± 2.6 and 1.7 ± 4.7 for Groups 1 and 2, respectively. In other studies, such as Sun and associates⁵ and Stone and colleagues¹⁵ a decrease in PSA was found to be 66% and 70%.

When considering safety issues, this technique shows satisfactory results. Up to 30% of the patients have complications, but the vast majority were Clavien–Dindo I–II. There were no differences in Clavien–Dindo I–II complications. The most frequent were hematuria, dysuria, and urgency, which usually are transient. Group 2 had higher III and IV Clavien–Dindo events. These were greater conversion and transfusion rates. Conversion has been reported in 0% to 8.4% of the patients,^4,10,12,13 and most of the time bleeding is the leading cause. Despite this, transfusion rate is low. Most series report 0% transfusion.^4,5,9,10 In this study, 2.4% of the patients in the case group received one unit. However, it is noteworthy to mention that the same patients who had a need for intraoperative bleeding control needed conversion and were more likely to receive blood transfusion. Of the six patients who required conversion three were performed by a surgeon who was beginning his learning curve, which reinforces the concept that complex cases should be performed by experienced surgeons. Another Clavien–Dindo III complication was clot retention.

Reintervention rate is low. Valdivieso and colleagues¹³ have the higher rate, 9%; however, they report on even bigger prostates (100–199 mL), with an average of 135 mL. Meskawi and associates¹² found that the main risk factor for reintervention was a low energy usage, <3 kJ/mL. After 1 year of the initial procedure the rate was 0.9% for both groups. In those patients where <3 kJ/mL was used, the reintervention rate was 7% and 13% after 2 and 3 years, whereas patients treated with more energy had 4% in both periods. In our study reintervention rate is considerably low (2.2% vs 2.3%) with a median follow-up of 47 months. Urethral stricture is rarely seen. Different series report 0.9% to 4.6% of this complication.^5,10 This is possibly explained because of the usage of a 23F sheath, rather than a 27F used in TURP. Incontinence after the first month is unusual. Campobasso reports a 6% urge incontinence rate, which disappeared after 1-year follow-up.⁹

Our study is performed in a single center, and despite this, it has one of the largest series reported in the literature. It also has one of the longer follow-ups (maximum range of 100 months), which shows the long-term favorable effects in patients. Even though this institution corresponds to a university hospital and teaching center with heterogeneity among staff in training and surgeons (novice, intermediate, and expert), overall results are encouraging.

Its limitations are the retrospective data collection and loss to follow-up. Various surgeons with different learning curves participated, and this can be considered a bias.

Conclusion

BPE management with Greenlight Laser 180 W XPS in prostates >80 mL is an effective technique with improvement in functional outcomes such as IPSS, QoL, and PSA. Despite finding slight differences in conversion and transfusion rates, surgeon experience appears to be an important variable to avoid these complications. Although low, the risk of reintervention in the medium and long term is inherent to BPE procedures and should be informed to patients before surgery.

Footnotes

Author Disclosure Statement

No competing financial interests exist.

Funding Information

No funding was received for this study.

Abbreviations Used

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