Photoselective Laser Vaporization of the Prostate in the Treatment of Bladder Outlet Obstruction in Advanced-Stage Prostate Cancer: A Single-Center Experience

Abstract

Background and Purpose:

The study in China is the first on photoselective vaporization of the prostate (PVP) applied to bladder outlet obstruction (BOO) or urinary retention from advanced-stage prostate cancer (PCa). The aim is to evaluate the efficacy and safety of PVP in the treatment of patients with BOO secondary to advanced-stage PCa.

Patients and Methods:

Forty-five patients (mean age 76.13±5.88 years, range 62–89 years) with BOO or urinary retention secondary to advanced-stage PCa received PVP with a potassium-titanyl-phosphate laser. The treatment outcome was evaluated with subjective and objective tests at 1, 3, 6, and 12 months after PVP using the International Prostate Symptom Score (IPSS), quality of life (QoL) score, postvoid residual (PVR) urine volume, and maximum urinary flow rate (Qmax). The operative time, indwelling catheterization time, and operative complications were also observed.

Results:

All 45 patients recovered without incident. The mean operative time was 50±7.6 minutes. The catheterization duration was 3.2 days (range 2–7 days). There was significant improvement in Qmax from 7.29±0.93 to 12.16±2.75 mL/sec after treatment at 12 months. Mean PVR volume decreased from 210.94±179.49 to 54.45±33.16 mL. Mean IPSS score decreased from preoperative 28.19±3.64 to postoperative 14.61±2.81 (P<0.05), QoL score decreased from 5.03±0.69 to 3.66±0.65 (P<0.05). There were no intraoperative adverse events. Postoperative complications included mild transient hematuria in 12 (26.7%) patients and mild dysuria in 11 (24.4%) patients within 4 weeks.

Conclusions:

The clinical results suggest that PVP is a safe, efficient, and less-invasive treatment for patients with BOO or urinary retention secondary to advanced-stage PCa.

Introduction

P rostate cancer (PCa) was a relatively rare malignancy in China 20 years ago. With rapid socioeconomic growth, the aging of the population and associated health problems present serious problems in China. Some recent reports indicate that the incidence of PCa in China is increasing rapidly such that it has become one of the most common cancers in elderly men.¹

As advanced-stage PCa progresses locally and cancer nodules grow into the urethra, the patient experiences difficult urination, retention, hematuria, and even renal function insufficiency. Thus, patients have bladder outlet obstruction (BOO) or retention. Moreover, they need long-term indwelling urethral or suprapubic catheters in their later years. A recent report showed the majority of PCa cases were revealed by urinary symptoms (75.9%) or bone pain (12.8%).² Another study reported more than 25% of PCa patients will have severe lower urinary tract symptoms (LUTS) or retention in their last years of life; 80% of these patients will need physical treatment.³ For these patients, curing retention, improving the quality of life (QoL), and avoiding further complications were the main aims of treatment.

To date, surgery remains the most effective treatment option for patients with urinary obstruction. Transurethral resection of the prostate (TURP) was generally considered the gold standard for the surgical relief of BOO. The morbidity of complications from TURP, however, is still rather high.⁴

The technology related to photoselective laser vaporization of the prostate (PVP) has evolved over the last 10 years. PVP can produce significant improvement in both clinical and voiding parameters with minimal morbidity.^5
–7 Based on these findings and the previous favorable PVP experiences of more than 1000 patients with benign prostatic hyperplasia (BPH) in our department, we consider advanced-stage PCa patients with BOO problems to be candidates for this surgical treatment.

The present analysis was to evaluate the clinical outcomes and durability of PVP in the treatment of patients with advanced-stage PCa with obstruction.

Patients and Methods

From February 2008 to December 2009, 45 patients (mean age 76.13±5.88 years, range 62–89 years) with long-term difficult micturition or urinary retention with a diagnosis of PCa received PVP therapy in our department. The patients were screened preoperatively by a complete history and physical examination, including a digital rectal examination (DRE), routine urinalysis and urine culture, serum creatinine and prostate-specific antigen (PSA) levels, MRI, radionuclide bone scintigraphy. The diagnosis of PCa was established by transrectal ultrasonography guided biopsies and pathologic evidence. Clinical cancer staging should be evaluated by DRE, pathologic evidence, MRI, and bone scintigraphy. Voiding symptoms were assessed using the International Prostate Symptom Score (IPSS). The effect on QoL was assessed using the QoL score. The maximum urinary flow rate (Qmax) was measured by uroflowmeter, and postvoid residual (PVR) urine volume was determined using transabdominal ultrasonography before and after treatment.

The patients had some significant comorbidities: Hypertension (n=17), coronary heart disease (n=8), myocardial infarction (n=2), chronic obstructive pulmonary disease (n=5), diabetes mellitus (n=8); an American Society of Anesthesiologists score was applied exclusively by anesthetists. Patients were excluded from the study if they had neurogenic bladder dysfunction.

The PVP procedure was performed using a GreenLight PV^® laser system (AMS, Minnetonka, MN) and an 80-W potassium-titanyl-phosphate (KTP) laser (Laserscope, San Jose, CA) emitting green light with a wavelength of λ=532 nm. A 600-μm optical fibrer with a 70-degree side-deflecting quartz element was inserted through the working channel of a 23F continuous-flow laser cystoscope. Sterile water at room temperature was used as the irrigation fluid. The patients received spinal anesthesia or general anesthesia.

PVP was performed from the bladder neck under video endoscopy guidance using a near-contact “painting” motion. During the PVP procedure, the laser power is reduced to 30 W; alternately, defocusing of the laser beam allows for the control of bleeding points to maintain a clear field of view.⁸ The median lobe was removed first to provide sufficient irrigation, and then the lateral, anterior lobe, and apical portion of the prostate were removed. The aim of the procedure was to achieve an adequate TURP-like, unobstructed cavity by vaporization of the obstructive prostate malignancies. A Foley catheter was placed at the end of the operation. The operative time was measured from the time of cystoscope insertion into the urethra to transurethral catheterization. A prophylactic antibiotic was given to all of the patients at induction, which was continued for 3 to 5 days after PVP.

The IPSS score, QoL score, PVR, and Qmax were reassessed after the PVP procedure and at each follow-up assessment (1, 3, 6, and 12 mos). Results are reported as the mean±standard deviation. Statistical analysis was performed using the SPSS 13.0 statistical software package (SPSS Inc, Chicago, IL). A probability of less than 0.05 was considered to be statistically significant. Operative effect evaluation included the operative time and indwelling catheterization time; operative complications were also assessed.

Results

Before surgery, 29 patients presented with urinary retention for an average of 4 months (range 3–10 mos) and needed an indwelling catheter; 16 patients had difficult micturition but no urinary retention for a duration of 8 months (range 6–12 mos). In these patients, the PVR volume was 210.94±179.49 mL (range 30–760 mL), the Qmax was 7.29±0.93 mL/s (range 4.7–9.1 mL/s). The mean age of patients was 76.13±5.88 years (range 62–89 years). Bone metastases were diagnosed clinically in 18 patients. There were 24 patients at stage T₃ and 21 patients at stage T₄. Mean prostate volume was 63.5±16.8 cc. The preoperative characteristics and demographics of the patients are summarized in Table 1.

Table 1.

Patient Characteristics and Demographics

Age (years)	76.13±5.88 (range 62–89)
Transurethral catheter	29 (64.4%)
Prostate volume (cc)	63.5±16.8 cc (range 30–136)
ASA category	I–II: 21
	III–IV: 24
PSA (ng/mL)	54.89±34.82 ng/mL (range 4.4–100)
Gleason score	8.7 (range 7–10)
Cancer staging	T₃: 24
	T₄: 21

ASA=American Society of Anesthesiologists; PSA=prostate-specific antigen.

All patients who underwent PVP survived the perioperative period safely. The median surgery duration was 50±7.6 minutes (range 40–75 min). The total laser energy applied averaged 26.6±6.7 kJ (range 23.6–30.0 kJ). No patient displayed evidence of dilutional hyponatremia (transurethral resection [TUR] syndrome); no blood transfusion was needed. The mean urethral catheter drainage time was 3.7 days (range 3–7 days). This catheter time is significantly longer than previously reported data in benign prostate disease.⁹ Three (6.7%) patients needed continuous bladder irrigation in the first 24 hours.

The assessments at baseline and for the mean follow-up after treatment for the Qmax, PVR, IPSS, and QoL measurement outcomes are presented in Table 2. Compared with the preoperative data, a urodynamic study revealed a statistically significantly increased Qmax (12.16±2.75 mL/s; P<0.01), and the PVR volume decreased from 210.94±179.49 to 54.45±33.16 mL (P<0.01) 12 months postoperatively. The mean IPSS and QoL score decreased significantly from 28.19±3.64 and 5.03±0.69 to 14.61±2.81 and 3.66±0.65 (P<0.01), respectively. Two patients were lost at 12 months of follow-up, and 1 patient died of cardiovascular disease.

Table 2.

Preoperative and Postoperative Follow-Up of 45 Patients with Bladder Outlet Obstruction or Urinary Retention Secondary to Advanced-Stage Prostate Cancer Who Underwent Photoselective Vaporization of the Prostate

		Follow-up (months)
Variable	Preoperative	1	3	6	12
Patients (n)	45	45	45	45	42
Qmax (mL/s)	7.29±0.93	13.20±5.61	12.69±3.51	12. 83±3.35	12.16±2.75
	(4.7–9.1)	(9.2–38.5)	(6.5–22.0)	(6.8–22.6)	(7.4–21.0)
P value		<0.01	<0.01	<0.01	<0.01
PVR (mL)	210.94±179.49	64.53±57.38	50.63±42.57	53.68±36.18	54.45±33.16
	(30–760)	(0–255)	(0–160)	(0–148)	(0–132)
P value		<0.01	<0.01	<0.01	<0.01
IPSS	28.19±3.64	14.63±2.82	13.63±2.59	14.25±3.32	14.61±2.81
	(23–35)	(8–21)	(10–24)	(8–21)	(11–23)
P value		<0.01	<0.01	<0.01	<0.01
QoL	5.03±0.69	3.13±0.42	3.16±0.45	3.38±0.49	3.66±0.65
	(4–6)	(2–4)	(3–5)	(3–5)	(4–5)
P value		<0.01	<0.05	<0.05	<0.05

Data presented as mean±standard deviation; all postoperative values were statistically different from the preoperative baseline.

Qmax=urinary flow rate; PVR=postvoid residual urine volume; IPSS=International Prostate Symptom Score; QoL=quality of life.

There were five patients in whom initial trials of voiding failed and who needed a catheter for 72 hours before voiding. Mild transient hematuria was identified in 12 patients (26.7%) for up to 3 to 4 weeks postoperatively. Mild transient urinary tract irritation, including urgency, frequency, and mild dysuria, was experienced by 11 patients (24.4%) within 2 weeks after the operation. Only two patients experienced transient incontinence for 1 week. The postoperative complications of PVP are presented in Table 3. None of these complications, however, necessitated any specific treatment.

Table 3.

Complications After Photoselective Vaporization of the Prostate

Type of complication	Case (%)
Transient hematuria	12 (26.7%)
Mild transient urinary tract irritation	11 (24.4%)
Transient incontinence	2 (4.44%)

Discussion

PCa has become one of the most common urinary cancers in men in China, and the incidence of PCa was 1.6/10⁵ person years (PY) in 1973 and 7.7/10⁵ PY in 2000 in Shanghai.¹⁰ Because the disease is typically in an advanced stage at the time of diagnosis, patients lose the opportunity to be treated with radical prostatectomy and have a short survival time after diagnosis. Despite the efficacy of androgen suppression and/or external irradiation for advanced PCa, all of these treatments need a long time to relieve obstructive symptoms. For hormonally relapsed PCa patients, it is always difficult to achieve an effective therapeutic result, and therapy usually leads to complications involving metastases.³ A study showed a series of 35 advanced PCa cases who received endocrine therapy; 46% had poor outcomes and needed long-term catheterization.¹¹

For late-stage PCa patients who are bothered by BOO or experiencing urinary retention, channel TURP has been the accepted treatment.⁹ The complication rate is rather high, however, such as hemorrhage, necessitating blood transfusion and the risk of TUR syndrome. Of 19 patients with PCa who underwent TURP, 42% failed to void postoperatively, with 29% needing further surgery and 21% needing long-term catheterization.¹² The outcomes of palliative TURP for LUTS showed PCa had a higher rate of failure without the use of a catheter and poor outcomes.¹³ The TURP procedure did not allow for the maintenance of a clear field of view when persistent venous bleeding occurred. Meanwhile, the approach might easily cause prostate capsule perforation and TUR sydrome when the tumor has already penetrated the prostatic capsule. At that time, the pressure of the perfusion fluid might trigger PCa cells to spread into the circulatory system circulation. TURP causes the dissemination of prostate cells into the circulation in a proportion of patients. These cells are then detectable by reverse transcription-polymerase chain reaction of PSA mRNA.¹⁴ One concern is that TURP, particularly when performed in patients with PCa, may cause the dissemination of tumor cells, which could increase the risk of metastatic spread.

PVP is an innovative procedure that uses high-power KTP laser energy to completely ablate obstructing prostatic tissue by vaporization. The outcome of PVP has been gratifying, with a significant reduction in symptoms, an increase in flow rate, a diminution of residual urine, and a low incidence of postoperative discomfort.⁷ PVP provides excellent relief from obstructive symptoms. The level of relief is comparable to that achieved with TURP, but PVP offers several advantages compared with TURP.¹⁵

In our PVP experience of more than 1000 patients with BPH, the first advantage of PVP was the outstanding hemostatic properties. The procedure was nearly bloodless, such that bladder irrigation was rarely needed, and the catheter time was relatively short. The second was the lack of fluid absorption because of the uniform and thorough tissue coagulation, especially for patients at high risk and with severe cardiac or pulmonary problems. Our study proved that no perforation occurred during the operation time because of the shallow penetration efficacy with PVP. With these qualities, PVP might easily be used to create a larger, relatively smooth prostatic cavity and might lower the risk of TUR syndrome and the dissemination of tumor cells into the circulation. A report described a lack of consensus as to whether circulating prostate cells in cancer patients were associated with a poorer outcome; the study showed a weak association during and after PVP.¹⁶

The third advantage of PVP was operative safety. PVP showed superior safety and recovery compared with TURP and the effects were maintained to 2 years.¹⁷ Based on these findings, PVP might be more appropriate for the aged and patients with obstructive urinary symptoms at high surgical risks.¹⁸ Postoperative therapies would benefit from use of the PVP procedure and would delay local tumor progression, because PVP provides a significant reduction of malignant prostatic tissue volume.¹⁹

In our present study, we successfully performed this technique to relieve the symptoms of BOO or urinary retention from advanced PCa. Our data suggest that a significant volume reduction can be achieved in both benign and malignant tissues, which significantly improved Qmax, PVR, IPSS, and QoL in our patients after treatment.

Despite the significant effectiveness and scarce complications associated with PVP, PVP was a simple, palliative treatment for late-stage PCa with BOO. The PVP procedure cannot remove the prostate malignancies thoroughly, so we should not regard PVP as a conventional treatment for advanced-stage PCa. This approach represents another potential tool for the treatment of advanced PCa. It is important for physicians to strictly control the operation indications to minimize any associated complications.

Conclusion

The PVP procedure produced a significant improvement in both symptoms and objective variables for patients with BOO secondary to PCa. Thus, the procedure was safe and effective. In addition, we considered that PVP reduced the volume of malignant prostatic tissue, postponed cancer progression, and may not cause tumor metastatic spread. PVP, however, is only a palliative therapy for PCa with obstruction. Despite these early and promising results, long-term follow-up and a larger cohort are needed to further validate these findings.

Footnotes

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

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