The Massively Enlarged Prostate: Experience with Photoselective Vaporization of the ≥100 cc Prostate Using the 180 W Lithium Triborate Laser

Introduction and Objectives

The advent of laser technology has created novel, yet safe and efficacious, alternatives for the surgical management of bladder outlet obstruction (BOO). Photoselective vaporization of the prostate (PVP), introduced in 1998, ¹ is an accepted modality for management of benign prostatic hyperplasia with obstruction. Meta-analyses have demonstrated that short- to mid-term outcomes are comparable to those of the gold standard transurethral resection of prostate, including bipolar transurethral resection of the prostate (TURP). ^{2 –4} History suggests that for the larger prostate, a controversial entity to define in itself, surgical management is often directed toward an open prostatectomy, which has a significantly increased risk of surgical morbidity when compared with endoscopic techniques. ⁵

The early 80 W KTP and 120 W HPS lasers have been utilized in large prostates, ⁶ with clinical outcomes similar to that of TURP ^{2 –4} and open prostatectomy. ⁷ This technology has not been readily taken up in the setting of a large prostate, as from a practical perspective there is a significantly longer operating time required. In addition to the increased tissue volume, longer operative times are attributable to damage of the laser fiber tip and the reduction in power associated with increased energy usage. ^8,9 The 180 W Greenlight XPS Lithium Triborate laser, available in 2010, differs from its predecessors with increased power, translating to increased surface area and equivalent depth of penetration, thus improving tissue vaporization efficiency without increasing the risk of capsular perforation. ¹⁰ The MoXy fiber has a protective cap, inbuilt cooling, and FibreLife feedback system to prevent fiber degradation and thus prolong fiber life and vaporization efficacy. ¹¹ In clinical practice, this has been shown to translate to the delivery of equivalent total energy with a shorter operating time and lower fiber usage compared with the 120 W. ¹² Clinical outcomes with the 180 W are equivalent to the 80 and 120 W in terms of safety and efficacy. ¹³

In this study, we report our early experience with the use of the 180 W LBO in large prostates, defined as a volume of greater than or equal to 100 cc.

Materials and Methods

All men who underwent PVP with the Greenlight XPS 180 W LBO by a single urologist at a single center had perioperative outcomes maintained in an ethics-approved prospective database. Retrospective analysis included all males who underwent PVP between November 2010 and February 2013 with a prostate volume greater than or equal to 100 cc. These men had lower urinary tract symptoms, consistent with BOO, appropriate for operative management in accordance with the American Urological Association (AUA) and the European Association of Urology (EAU) guidelines. Men with a prostate volume of less than 100 cc were excluded from the study. Men on active surveillance for low-grade low-volume prostate cancer were included in the trial; however, men who were on active treatment for prostate cancer were excluded.

Prostate volume, prostate-specific antigen (PSA) levels, flow study voided, and postvoid residual (PVR) volumes were measured preoperatively. Perioperative measures included operative and laser time, total energy utilized, and postoperative length of catheterization and hospital stay. Functional outcomes, including International Prostate Symptom Score (IPSS), quality of life (QoL) Index, and maximum urinary flow rate (Qmax), were measured at baseline and at 3 and 6 months postoperatively. PSA was routinely measured at 3 months postoperatively only.

A 23F Storz continuous flow laser cystoscope with a MoXy liquid-cooled, steel tipped-fiber was used at 80 W for the creation of a working space and incrementally increased to 180 W with the formation of appropriate space, as has been previously described by the International Greenlight Users Group. ¹⁴ The irrigation fluid used was room temperature physiologic saline. All patients were given routine antibiotic prophylaxis perioperatively and had a urethral catheter placed at the conclusion of each case, the type of indwelling catheter (IDC) was determined by the degree of hematuria.

Statistical analysis was performed using a paired two-tailed Student's t-test on Microsoft Excel 2011. Statistical significance was defined as p<0.05.

Results

Of 173 males who underwent PVP in the 28-month time frame, 35 patients fulfilled the inclusion criteria. These men had a median age of 70 years (interquartile range [IQR] 66–79) with a median prostate volume of 132 cc (IQR 118–157) and median preoperative PSA of 7.1 ng/mL (IQR 4.4–9.0). Preoperatively, 11/35 (31%) men were in urinary retention requiring catheterization. Men without catheters at baseline (n=24) had a median Qmax of 9.5 mL/s (IQR 6.8–11.0 mL/s), voided volume of 160 mL (IQR 114–213 mL), and PVRs of 123 mL (IQR 60–310 mL). Eleven of the 35 (31%) men were taking anticoagulant medications, all as single agents and all were continued pre- and postoperatively. These agents included aspirin (n=4), Asasantin (n=1), warfarin (n=5), and Pradaxa (n=1). Two men were on active surveillance with biopsy-proven, low-grade low-volume prostate cancer.

Perioperative outcomes demonstrated a median laser time of 75 minutes (IQR 65–98 minutes), operating time 103 minutes (IQR 82–129 minutes), and energy use of 750 kJ (IQR 638–1011 kJ). The majority of men had a 16F Bard Biocath placed at the conclusion of the case, however, six men had three-way 20F silicon irrigating catheters placed as a precaution in vascular glands; irrigation was not required for any of these cases. The median postoperative length of stay was 20 hours and length of catheterization 12 hours. Thirty-two of the 35 men (91%) passed an initial trial of void and 33/35 men (94%) were discharged from hospital catheter free.

For paired analysis (Table 1), all men with catheters preoperatively (n=11) were excluded from functional analysis as there was no baseline comparator. At 3 months, one patient did not follow up as he saw another doctor, one did not follow up as he lived interstate, and another patient lived interstate and filled out the IPSS and QoL at 3 months only, however, did not undertake urinary flow studies. A fourth patient was unable to void at preoperative flow studies and so excluded from Qmax and PVR, however, included for evaluation of IPSS and QoL at 3 and 6 months. At 6 months, further 10 patients did not follow up as they lived far away, did not attend their appointment, or had not reached 6 months post-PVP.

A total of 12 adverse events in 11 (30%) men were recorded and outlined in Table 2. Of these, 11 were Clavien–Dindo Grade I or II complications, 1 Grade IIIa complication, and there were no mortalities.

Of the patients recatheterized, one passed a trial of void on the subsequent day. Of the men discharged home with a catheter, one patient effectively passed a trial of void 5 days postdischarge. The other was taught clean intermittent self-catheterization, which had been ceased by the 3-month follow-up. All men who followed up were catheter free at 3 months. The overall rate of urosepsis, defined as a urinary tract infection with associated fevers requiring intravenous antibiotics, was relatively high (3/35, 9%). This is reflective of the large proportion of the group with catheters in situ preoperatively. Indeed, two of the three patients were in retention before PVP. One of the gentlemen with urosepsis was in acute urinary retention with a concurrent extended-spectrum beta-lactamase infection, so underwent PVP on intravenous (IV) antibiotics when stable and continued on antibiotics for a prolonged course postoperatively, as per the guidance of Infectious Diseases. The other two patients developed urosepsis postoperatively and settled with IV antibiotics.

The Clavien–Dindo Grade IIIa complication occurred in a 66-year-old gentleman with atrial fibrillation on warfarin, whose indication for intervention was recurrent clot urinary retention, with an IDC in situ preoperatively and a prostate volume of 170 cc. He was recognized to have a posterior capsule perforation intraoperatively after 1020 kJ laser energy vaporization, which required interventional percutaneous drainage of the extraprostatic space. He was observed in the intensive care unit as a precaution only and did not require any intervention in the form of transfusion, inotropic support, or intubation.

Discussion

Our early experience with PVP in the large prostate suggests that perioperative outcomes are similar to that of the smaller average gland with the 180, 120, and 80 W. In particular, the short median duration of catheterization (12 hours) and length of hospitalization (20 hours) compares favorably with previous PVP studies ² and is significantly shorter compared with transurethral resection of the prostate (TURP) ¹⁵ and open prostatectomy (OP). ⁷ Perioperative outcomes, in particular IPSS, QoL index, Qmax, and PVR at 3 and 6 months, are comparable with the outcomes of previous randomized controlled trials comparing PVP with TURP and OP. ^2,7,15 As expected, the operating time, laser time, and energy utilization were all greater when compared with PVP in smaller glands in accordance with the increased size of the gland. ¹³

Complication rates are similar to previous reported studies of PVP ¹⁶ and overall lower than those reported for TURP ^{2 –4} and OP. ⁷ No men in our group required blood transfusions compared with quoted rates of within 2% in TURP ¹⁵ and 8% in OP. ⁷ There were no episodes of TUR syndrome compared with quoted rates of 0.8% after TURP. ¹⁵ There were also no reports of stress urinary incontinence at 3 and 6 months of follow-up compared with 3% in TURP and 6% in OP. ⁵ The lack of blood transfusions and the catheter-free discharge rate are similar to experiences with holmium enucleation of the prostate (HoLEP). ¹⁷

The overall tissue resection with ablative techniques such as PVP may never equal enucleation techniques such as the traditional open prostatectomy or more recent laser techniques such as HoLEP. PVP is advantageous with respect to the shorter learning curve, ¹⁸ particularly in comparison with the steep learning curve of HoLEP, ¹⁹ and the lower risk of peri- and postoperative complication, particularly when compared with an open prostatectomy. One must consider that with fewer surgeons routinely performing open prostatectomies, the complication rate is likely to increase in accordance with the experience of the surgeon. Many patients will be willing to accept a lower volume of tissue resection and a potentially higher rate of reoperation when this is coupled with a significantly lower surgical morbidity and equivalent short- and medium-term postoperative outcomes. This is particularly pertinent in the aging population, where patients with a greater number of comorbidities may have a significant QoL benefit from a less invasive technique. The ability to utilize PVP safely in the context of continuing anticoagulation will enable men who previously declined operative intervention a chance of improved QoL, potentially catheter free. ²⁰

The collation of data representative of a single-center, single experienced PVP surgeon is a limitation of this study, as the peri- and postoperative outcomes may not reflect the outcomes of less experienced centers. One would expect longer operating and laser times with higher energy utilization in less experienced hands. It may also be expected that the low rates of postoperative complications identified in this study may not be representative of less experienced centers, as has been previously demonstrated. ¹⁶ The outcome measures are limited by the absence of a comparator limb and a lack of long-term data outcome measures, which may be explained by the relatively new technology.

Conclusion

The initial experience of PVP with the 180 W LBO Greenlight laser in the large prostate, greater than or equal to 100 cc, suggests that it is a safe and efficacious alternative to TURP and OP. The 180 W PVP in the large prostate has acceptable morbidity and equivalent short- and medium-term postoperative outcomes and has no significant increase in morbidity associated with the anticoagulated subset of the population. A long-term follow-up is necessitated for the comparison of late complications.