Abstract
Background: To evaluate the efficacy and safety of GreenLight HPS™ (High Performance System) laser photoselective vaporization prostatectomy (PVP) for the treatment of benign prostatic hyperplasia (BPH) in patients of different age groups. Methods: 164 consecutive patients were stratified into two groups: age <70 (group I, n = 93) and age ≥70 (group II, n = 71) years. Transurethral PVP was performed using a GreenLight HPS™ side-firing laser system. Voiding parameters 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 prostate volume (I: 58.7; II: 73.6 mL) and serum prostate-specific antigen (I: 1.9; II: 2.9 ng/mL), while American Urological Association Symptom Score (AUASS), Quality of Life (QoL), maximum flow rate (Qmax), Sexual Health Inventory for Men (SHIM) and post void residual (PVR) were similar (p > 0.05) between groups. No significant differences in laser utilization, energy usage and operating time were noted. Clinical outcomes (AUASS, QoL, Qmax, 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. The incidence of adverse events was low and similar in both groups. Conclusions: The results suggest that age has little effect on the efficacy and safety of GreenLight HPS™ laser PVP.
Background
Benign prostatic hyperplasia (BPH) is a primary cause of lower urinary tract symptoms (LUTS) in the aging male. With prolonged life expectancy worldwide, more symptomatic BPH patients will require surgical intervention. The evolution of minimally invasive surgical options has provided treatment alternatives to the gold standard transurethral resection of the prostate (TURP). Such a modality is the potassium-titanyl-phosphoate (KTP) laser photoselective vaporization prostatectomy (PVP) [Citation1]. This laser utilizes a 1064 nm neodynium: YAG (Nd:YAG) laser light that is emitted through a KTP crystal which doubles the frequency and halves the wavelength to 532 nm, producing the “green” light. It 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 [Citation2]. Numerous studies [Citation3–5] have shown that KTP laser PVP produces clinical outcomes similar to those following TURP, while having distinct advantages over the latter, making it an attractive surgical alternative. The power of the KTP laser PVP has increased over time, being popularized with the 80W model.
In 2006, the GreenLight HPS™ (High Performance System) laser (American Medical Systems, Minnetonka, Minnesota, USA) was introduced. In this laser, a diode pumped Nd:YAG laser light is emitted through a lithium triborate (LBO) instead of a KTP crystal, providing a power range of 20–120 W instead of the 30–80 W range of its predecessor [Citation6]. This substantial improvement results in increased prostate vaporization efficiency. Several authors have reported the impact of prostate size, prostate-specific antigen (PSA) and age on the results of KTP laser PVP [Citation7–9]. The impact of age on the clinical outcomes of GreenLight HPS™ laser PVP, however, is yet to be assessed. In the present study, we review our experience with GreenLight HPS™ laser PVP to determine if age impacts on the efficacy and safety of this procedure with a maximum follow-up of 36 months.
Methods
Following Institutional Review Board approval, prospectively collected data from records of consecutive patients 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 November 2010 were reviewed. Informed consent was waived for the reporting of deidentified and cumulative data. Surgical intervention was indicated according to BPH guidelines of the American Urologic Association: persistent moderate to severe LUTS despite prior medication and/or surgery, refractory urinary retention, persistent gross hematuria (CT urography and cystoscopy normal), bladder stones and recurrent urinary tract infection (UTI) [Citation10]. 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 complete blood count, electrolytes, renal function and serum PSA, uroflowmetry for maximum flow rate (Qmax), post void residual (PVR) and transrectal ultrasonography (TRUS) measurements of prostate volume. If patients were found to have an elevated PSA or abnormal digital rectal examination (DRE), TRUS-guided prostate biopsies were performed preoperatively to exclude prostate cancer (PCa). Patients with prior surgery for BPH, PCa, urethral strictures, bladder tumors or bladder dysfunction due to neurologic disorders were excluded from study [Citation11].
One hundred and sixty-four consecutive patients were stratified into two groups: age <70 (group I, n = 93) and age ≥70 (group II, n = 71) years [Citation12]. Transurethral PVP was performed using a GreenLight HPS™ side-firing laser system as has been previously described [Citation2]. Anticoagulant medications (acetylsalicylic acid, clopidogrel and warfarin) were recommended to be discontinued when possible. Perioperative antibiotic prophylaxis was provided and general or spinal (rare, used when recommended by Anesthesiologist) anesthesia was employed. A 23 F continuous-flow cystoscope with a 30° lens was used with the laser set at 120 W for vaporization and 30 W for coagulation. Room temperature normal saline was used as the irrigation fluid. A 20 F urethral catheter was placed at the end of procedure. A voiding trial was performed 2 hours postoperatively. If patients were unable to urinate, a urethral catheter was replaced prior to discharge and returned to our outpatient clinic for a second voiding trial the following morning. Patients who failed the second voiding trial were recommended to keep the catheter for 7 days. All PVP procedures were performed on an outpatient basis as patients were discharged home the day of surgery. Perioperative parameters, including laser utilization, delivered energy, operating time, 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 months follow-up, with subsequent serum PSA determinations performed as medically indicated. Adverse event data were collected and analyzed [Citation13].
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. The student t test and χ2 test were used for statistical validation, with a two-sided p < 0.05 considered to indicated statistical significance.
Results
There was no significant difference in the baseline data (AUASS, QoL, SHIM, Qmax, PVR, ASA score, anticoagulant usage and medication for BPH) between the two groups (p > 0.05). Older patients tended to have a higher prostate volume (I: 58.7 ± 32.4; II: 73.6 ± 39.8 mL, p = 0.011), higher serum PSA (I: 1.9 ± 2.0; II: 2.9 ± 2.4 ng/mL, p = 0.008) and lower α-blocker usage (I: 44.1%; II: 26.8%, p = 0.033). Patients who presented with a serum PSA ≥ 4 ng/mL accepted a TRUS-guided prostate biopsy that confirmed benign pathology. Two patients (one 85-year-old patient having a serum PSA value of 5.9 ng/mL and one 81-year-old patient having prior negative prostate biopsies and a stable serum PSA of 10.1 ng/mL for 15 years) in group II deferred prostate biopsy. The incidence of urinary retention at presentation was similar in both groups (p = 0.608). ().
Table I. Patient demographics.
Mean laser time (I: 12.7 ± 10.9; II: 15.6 ± 9.3 minutes, p = 0.082), operating time (I: 30.9 ± 25.3; II: 36.1 ± 21.7 minutes, p = 0.181) and energy usage (I: 87.1 ± 76.3; II: 103.9 ± 63.6 kJ, p = 0.144) were longer and higher in group II, but did not reach statistical significance. Two patients in group II underwent spinal anesthesia due to medical comorbidities. No patient developed postoperative hyponatremia and no blood transfusion was required. All patients were discharged home the day of surgery. 55 (59.1%) patients in group I and 42 (59.2%) patients in group II were catheter-free at hospital discharge (p = 1.000), while catheter-free rates increased to 92.5% and 93.0% (p = 1.000), respectively, the day after surgery ().
Table II. Perioperative parameters.
Symptomatic improvement of LUTS was noted almost immediately following urethral catheter removal, with significant improvements in AUASS, QoL, Qmax and PVR from baseline (p < 0.05) that were durable to 36 months in both groups. Postoperative SHIM remained stable compared to baseline during the follow-up interval in each group and were similar (p > 0.05) between the two groups (). Mean prostate volume measured by TRUS (single operator blinded to the baseline prostate volume) showed a similar reduction in both groups (I: 53.0%; II: 51.9%, p = 0.692) at the 3 months interval. Excluding the patients (I: 24; II: 29) who were on a 5α-reductase inhibitor of minimum six months duration preoperatively, the mean serum PSA reduction 3 months post surgery (I: 34.0%; II: 39.1%, p = 0.543) was also similar between the two groups.
Table III. Clinical outcomes.
One (I: 1.1%; II: 1.4%, p = 0.506) patient in each group had nonsignificant intraoperative bleeding that was successfully controlled with the coagulation mode of the laser system without the need for conversion to TURP or open surgery. The incidence of adverse events were low and similar between the two groups: clinically nonsignificant hematuria (I: 54.8%; II: 64.8%, p = 0.205), UTI (I: 5.4%; II: 4.2%, p = 1.000), transient irritative voiding symptoms (I: 2.2%; II: 4.2%, p = 0.653), de novo retrograde ejaculation (I: 37.7%; II: 21.2%, p = 0.152) and delayed hematuria (I: 2.2%; II: 0%, p = 0.506). No prostate capsular perforation, TUR syndrome, urinary incontinence, bladder neck contracture or urethral stricture was reported during the follow-up interval ().
Table IV. Adverse events.
Discussion
BPH in the aging male will increase in socioeconomic and medical importance at a time of increased life expectancy and aging of the baby boomer generation. Due to progression of LUTS secondary to BPH and failure of maximal medical therapy, up to one-third of patients will eventually require surgical intervention [Citation14]. With the evolution of surgical laser technologies, the 120W GreenLight HPS™ laser PVP has established itself as a reliable surgical option for the treatment of patients with symptomatic BPH in comparison with TURP [Citation15,Citation16]. It has a relatively short learning curve and has gained increasing acceptance among urologists worldwide. The procedure allows for almost bloodless prostatic tissue removal and low complication rates with sustained improvements in a wide range of patients, including specific patient populations on anticoagulants and with large volume prostates [Citation17,Citation18]. Our initial results with the GreenLight HPS™ laser PVP were optimistic, having excellent clinical efficacy and safety outcomes in both short- and intermediate -term follow-up [Citation11,Citation13].
In our present study, older patients tended to have larger prostates (I: 58.7 ± 32.4; II: 73.6 ± 39.8 mL, p = 0.011) and higher serum PSA values (I: 1.9 ± 2.0; II: 2.9 ± 2.4 ng/mL, p = 0.008). Tasci et al. reported that patients with prostate volumes over 70 mL had significantly longer operative time and higher applied energy than patients with smaller prostates (< 70 mL) [Citation17]. Despite this, differences in the intraoperative parameters (laser utilization, energy usage, operating time), although noted, did not reach statistical significance. This may be because 40 of 71 (56.3%) patients in group II had a prostate volume less than 70 mL, which may have offset the statistical significance between the two groups. Almost immediate and durable improvement of both subjective (AUASS, QoL) and objective (Qmax, PVR) voiding parameters were recorded up to 36 months follow-up in both groups, while no significant difference existed between the two groups. All our GreenLight HPS™ laser PVP procedures were performed on an outpatient basis. More than half the patients (I: 59.1%; II: 59.2%, p = 1.000) were able to successfully void following surgery and discharged from hospital without a urethral catheter. 86 (92.5%) group I and 66 (93.0%) group II patients were catheter-free the morning following surgery (p = 1.000). Although older patients may tardily adapt to anatomic changes [Citation9], group II patients had similar catheter-free rates compared to those of group I.
Older patients with larger prostates did not compromise the clinical efficacy of GreenLight HPS™ laser PVP in our patient series. This contrasts the functional results reported by Buse et al. [Citation9], where age independently and strongly affected IPSS and QoL results 12 months after 80W KTP laser PVP. The discrepancy may be due to the different age cut-off (62 vs. 70 years) defined and our GreenLight HPS™ laser system, which may have offset the impact of age-related changes on the efficacy of surgery.
Of equal importance to the efficacy of a surgical procedure is its safety. Adverse events encountered in our study included nonsignificant intraoperative bleeding and postoperative hematuria, transient irritative voiding symptoms, UTI, urinary retention requiring transient recatheterization and retrograde ejaculation. The incidences of these events were low and similar between the two groups (p > 0.05). Nonsignificant intraoperative bleeding was encountered in one procedure in both groups due to the larger vascular glands. This was controlled appropriately in the coagulation mode of the GreenLight HPS™ laser set at 30W. To minimize the risk of intraoperative bleeding, discontinuation of ongoing anticoagulant medications is recommended if possible. No patient required blood transfusion and no episode of prostate capsular perforation or TUR syndrome was noted in both groups. Despite having no clinically significant intraoperative bleeding and postoperative hematuria, the serum hemoglobin value was decreased to a statistically significant extent in both groups. Hemodilution secondary to intravenous fluid resuscitation may account for this finding. Postoperative urinary retention requiring temporary catheterization may be attributed to detrusor underactivity rather than incomplete resection [Citation12]. The lack of bladder neck contracture in this study may result from our surgical approach in which the bladder neck is aggressively opened with avoidance of vaporization of the urothelium at the 12 o’clock position. No surgical retreatment has been necessary for recurrent LUTS at the time of writing this manuscript.
Only 34 (I: 20; II: 14) and 26 (I: 15; II: 11) patients reached the 24- and 36-month follow-up interval, respectively, at the time of this writing, which may have some statistical limitation. Factors that may have contributed to this include the insufficient time interval post surgery and the geographic distribution of our patients (many of whom reside >3 hours from our institution) limiting follow-up compliance.
Conclusion
Age has little effect on the efficacy and safety of GreenLight HPS™ laser PVP. It is a reliable treatment option for most patients with symptomatic BPH, as almost immediate and durable improvement in clinical outcomes is possible. Further substantiation of these results by data from either large prospective trials or continued long-term follow-up would be of benefit.
Acknowledgements
The authors are thankful for the contributions from Glenn M. Sulley, RN, Colleen F. Davis, MA, DeAnna J. Kuykendall, MA, Raquel Carranco, MA and Maria E. Gonzalez, MA.
Declaration of interest: Carson Wong, MD is a consultant for American Medical Systems, Inc. This work was supported in part by the Endourological Society and Cook Urological Corporation.
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