Is transurethral needle ablation of prostate out of fashion? Outcomes of single session office-based transurethral needle ablation of prostate in patients with symptomatic benign prostatic hyperplasia

Transurethral needle ablation (TUNA) is a minimally invasive procedure for the treatment of symptomatic benign prostatic hyperplasia (BPH) [1]. It utilises low-level radiofrequency energy to cause selective necrosis of the hyperplastic prostatic tissue whilst preserving the urethra and adjacent structures. Although transurethral resection of the prostate (TURP) remains the gold standard for treatment of BPH, office-based TUNA presents itself as an attractive alternative because of its minimal invasiveness and avoidance of general anaesthesia. TUNA was offered as a single-day office procedure at our centre. We reviewed the outcomes of TUNA performed at our local tertiary unit and affirm its applicability.

This study is approved by National Health group domain specific review board (approval number: NHG DSRB Ref: 2017/01037). Informed consent was waived by the board. Clinico-epidemiological data of 121 patients who had undergone TUNA for symptomatic BPH was retrospectively collected from June 2008 to March 2017. Our selection criteria/indications for patients suitable for TUNA had one or more of the following characteristics: those who had side effects from medical treatment of BPH and unable to tolerate it, those who were not keen for long-term medical therapy, those who failed medical therapy (alpha blocker or 5-alpha reductase or combination drug therapy) due to a lack of benefit or improvement of their lower urinary tract symptoms, and those who were unfit for general anaesthesia.

Patients who were possible candidates for TUNA underwent thorough history taking and examination. Parameters such as the International Prostate Symptom Score (IPSS) and quality of life (QOL) were assessed. Investigations such as urinalysis, measurement of prostate specific antigen (PSA) levels, urine culture, uroflowmetry, bedside ultrasound of the bladder and prostate were performed.

Patients with an abnormal digital rectal examination, or PSA greater than 4.0 ng/mL, had to undergo a trans-rectal ultrasound (TRUS) guided needle biopsy of the prostate to exclude prostate cancer. There is no exclusion criteria for the volume of the prostate but patients with intra-vesical protrusion of the prostate (IPP) of grade III were not offered TUNA. Lastly, patients who had positive urine cultures were treated with antibiotics and had a repeat culture to document clearance prior to TUNA.

All suitable patients were then given rectal suppositories on the night prior to procedure and on the day of procedure and a course of prophylactic antibiotics (ciprofloxacin 500 mg twice a day for one week or augmentin three times a day for one week if patient had ciprofloxacin allergy or previous urine culture is resistance to ciprofloxacin). On the procedural day, patients were given 160 mg of intramuscular gentamicin. A flexible cystoscopy was performed prior to TUNA to exclude high bladder neck, bladder cancer and urethral stricture. Patients were then given 7.5 mg of oral midazolam. TRUS was performed to measure the prostatic volume and maximal transverse length under a periprostatic nerve block using 10 mL of 1% lignocaine. The bladder was decompressed with urinary catheter before subsequent instillation of 60 mL of 2% cold lignocaine solution. TUNA was then performed under direct vision by a single trained urologist using the Prostiva® RF Therapy by Urologix Inc. (Medtronic, MN, USA). The length of the needle and the number of lesions were calculated from measurements obtained during TRUS. Eight areas were ablated for all patients–3 at the bladder neck, 2 at mid-zone and 3 at the apex of the prostate.

Patients were asked to rate their discomfort levels during the procedure using a 10-point scale; 0 for no discomfort to 10–the worst pain the patient had ever experienced. All patients were monitored post-procedurally for 4 hours. They returned home with an indwelling catheter, which would subsequently be removed in a few days.

All patients had scheduled follow-up visits at 1 month, 3 months, 6 months, and 12 months with IPSS, and uroflowmetry performed at each visit. After the one year, all patients were given annual follow-up appointments. However, patients were also given the option of no-follow-up/discharge when they reported personal satisfactory levels of symptomatic improvement and/or showed improvement in IPSS and uroflowmetry parameters at any time of the follow-up visit but were advised to come back when symptomatic again.

IBM SPSS Statistics ver. 24.0 (IBM Corp., Armonk, NY, USA) was used for statistical analysis. Patients??demographic and baseline clinical characteristics were analysed descriptively. The Wilcoxon signed-rank test was used to compare the IPSS, QOL and maximum urinary flow (Qmax) scores between baseline and the best result during the follow-up. The Kaplan–Meier method was used to study the time to secondary treatment, which includes any medical therapy or operation, and also i) sub-group analysis of a group of patients whom although initially responded to therapy, could not be maintained on therapy either due to side effects or unwillingness to take medications for a prolonged duration, versus another group of patients who did not show response to medical therapy at all and ii) subgroup analysis patients who underwent TUNA based on prostate volume. Log-rank test using Bonferroni adjustment was used for all pairwise comparisons, while Cox regression was used for the multivariate comparisons. The Cox proportional hazard regression was used for the multivariate analysis.

Our study represents the first single-setting office-based TUNA requiring minimal sedation done in the Asian community. TUNA is able to significantly improve IPSS, QOL and Qmax. The complication rates for TUNA were low in our series, with no associated mortality and only 2 of 121 (1.7%) requiring hospitalisation post procedurally. When applied to selected patients, TUNA is an effective and reasonably safe alternative for the treatment of symptomatic BPH.

In a study performed by Leocádio et al. [2], the methods of anaesthesia were similar to ours. However, no periprostatic administration of lignocaine was performed. This study reported a mean pain score of 4.8 compared to 3 in our study. This suggests that the additional use of a periprostatic nerve block with lignocaine may play a significant role in pain relief.

In our study, TUNA significantly improved BPH parameters (65% improvement of IPSS, 75% improvement of QOL and 35% improvement in Qmax) post-TUNA when compared to pre-TUNA values. Our results corroborate the findings of Bouza et al. [3], which further affirms the efficacy of officebased TUNA .

In our study, the median time to symptom recurrence was 6.123 years. In comparison, a 2007 study by Rosario et al. [4] reported a median time to symptom recurrence of 20 months. Although this study demonstrates a higher efficacy of TUNA compared to Rosario et al. [4], this may be confounded by the fact 100% of their recruited patients had failed initial medical therapy, whereas in our study, only group 2 had failed medical therapy.

Even in group 2, 54.0% managed to remain symptom-free by the 5th year of follow-up and the median time to symptom recurrence was 5.390. This demonstrates a higher efficacy of TUNA in prolonging median time to symptom recurrence, and establishing long-lasting symptom-free intervals. In a meta-analysis on TUNA by Bouza et al. [3], only 237 of 1,036 patients treated with TUNA required medical and/or surgical treatment there after amounting to a rate of only 19.07%. There was otherwise no mention of the period of follow-up and the median time to symptom recurrence. Our study showed that only 9.5% of the patients required additional procedure or operation post 5th years of treatment. This result is comparatively better than those reflected by Bouza et al. [3] which showed that 186 of 1,036 patients (18.0%) eventually required surgical interventions, although the follow-up interval was not clearly stated in this meta-analysis. Our study also proposed good efficacy of TUNA compared to the study by Rosario et al. [4], the latter demonstrating that 48.5% of patients required eventual surgical intervention.

Although our study did not identify factors for treatment failure, we excluded patients with grade III IPP. This may account for our high success rate compared to Rosario et al. [4]. Wang et al. [5] which suggested that patients with IPP grade III with small prostates would be achieve better treatment outcomes with TURP. Purposeful exclusion of patients with IPP grade III would improve the overall effectiveness of TUNA, particularly in terms of achieving long-lasting control of symptoms.

In terms of cost benefits, the cost of TUNA in our institution is estimated to be United States dollar (USD) $3,600 and the cost of combination medical treatment is estimated to be USD$1,080 per year, with an estimate of 3 years and 4 months to reach breakeven. The mean time to symptom recurrence of 6.123 years in our study, demonstrating cost effectiveness to perform the procedure.

Although not statistically significant in our series, TUNA seemed to be beneficial for patients who chose to have the procedure due to intolerance to medication or reluctance for chronic medications. It may be assumed that these patients had a milder form of BPH compared to those who had already failed medical therapy (group 2), and hence naturally performed better after TUNA. This author feels that TUNA is a feasible alternative to patients with symptomatic BPH who are intolerant to the side effects of alpha-blockers. TUNA may also be offered to those who have failed medical therapy, although more in-depth evaluation is advised (prostate size, IPP) to exclude those that may benefit more from upfront TURP. TUNA was seen to be beneficial for patients with smaller prostate volume especially for prostate volumes ranging from 20.00 to 30.00 mL (although this was not statistically significant). As TUNA can be done without general anaesthesia, TUNA will benefit patients who have high risk of general anaesthesia and have a small prostate volume of 20 to 30 mL with symptomatic BPH. The limitations of our study include a small sample size, and not being able to trace patients who had a deterioration of BPH symptoms after being discharged and had not sought treatment from public hospitals. This could have led to an over-estimation of our relapse-free rate.

This study is the first single-day office TUNA study done in an Asian community. Our study has shown that TUNA is a safe and effective procedure with patients with symptomatic BPH. It is suitable for those cannot tolerate the side effects of medical therapy or those whom are not keen for long term medical therapy, high risk of general anaesthesia and/or have a small prostate volume of 20 to 30 mL.