An interventional study of Transcutaneous Electrical Nerve Stimulation (TENS) and Sham Transcutaneous Electrical Nerve Stimulation in Prostate Cancer (Diagnosis), Prostate Biopsy and Pain, Procedural, sponsored by Medical University of Gdansk. Recruiting at 1 site in Poland. Open to male participants aged 40 Years and older. Per ClinicalTrials.gov, last updated 2026-08-13.
Sponsored by Medical University of Gdansk · Not applicable, Interventional, and Supportive care
Transperineal prostate biopsy is a safe and effective method of diagnosing prostate cancer. When performed under local anaesthesia in an outpatient setting, it can cause significant pain, particularly during the periprostatic nerve block - the injection of local anaesthetic around the prostate. Better pain management during this procedure may improve patient comfort and encourage wider use of the transperineal approach.
Transcutaneous electrical nerve stimulation (TENS) is a non-invasive, low-cost method of pain relief that works by delivering mild electrical impulses through the skin. A preceding pilot study at our centre (n=84) found that TENS used alongside local anaesthesia was associated with significantly lower pain scores during periprostatic nerve block and biopsy sampling, with no device-related complications.
This study aims to confirm these findings in a larger, formally powered, triple-blind, randomized controlled trial. Participants will be randomly assigned to receive either active TENS or sham TENS (electrodes applied but no electrical current delivered) in addition to standard local anaesthesia. Neither the participant nor the operating urologist will know which group the participant is in. Pain scores are written down by the participant himself, so nobody asks him for a number during the procedure. Stimulation may feel strong, weak or not noticeable at all, and feeling nothing does not mean a participant is in the inactive group.
Pain intensity will be assessed at four stages of the procedure using a 0-10 numeric rating scale. Participants will be followed up at 30 days after the biopsy.
This is a single-centre, prospective, randomized, sham-controlled, two-parallel-group superiority trial. It builds on a preceding single-centre randomized sham-controlled pilot (TENS 1, n=84, 1:1:1 allocation to active TENS, sham TENS and local anaesthesia alone), which demonstrated large effect sizes for TENS-associated pain reduction during periprostatic nerve block and biopsy sampling, with no difference between sham and local anaesthesia alone at any stage and no device-related adverse events. The pilot was retrospectively registered, was explicitly hypothesis-generating and had no formal power calculation. The present trial addresses each of these limitations: it is prospectively registered, formally powered against a pre-specified minimum clinically important difference, and restricted to two arms on the basis of the pilot finding that sham stimulation is an inert control condition.
Stimulation is delivered through a single channel using two electrodes placed paraperineally, one on each side, so that the current path crosses the perineum transversely over the S2 to S4 dermatomes, corresponding to the pudendal innervation of the perineum and the periprostatic region. The single-centre design is deliberate: all biopsies are performed at one institution using the same fusion platform, the same local anaesthesia technique and the same stimulation protocol as the pilot, which minimises inter-operator and inter-centre variability and preserves methodological continuity, at an acknowledged cost to external validity.
Pain scores are self-recorded by the participant on a paper form at fixed procedural stages, each announced in standardised wording by the operator, who is blinded to allocation. No member of the study team asks the participant for a pain score at any point. This differs from the pilot, in which scores were collected verbally, and the change is accounted for when pilot and trial effect sizes are compared.
Sample size is not based on the pilot effect estimate, because effect sizes from small pilot trials are systematically inflated. The planning scenario uses the pre-specified minimum clinically important difference of 1.5 NRS points with an assumed standard deviation of 2.0 (Cohen's d = 0.75), a two-sided alpha of 0.05, a Mann-Whitney U test and an asymptotic relative efficiency adjustment of 0.955. The trial adopts 60 evaluable participants per group, which provides 80% power for effects of d = 0.52 or larger and retains 76% power in a conservative robustness scenario of d = 0.50. Recruitment is inflated for dropout and non-evaluable primary outcomes. No interim analysis is planned.
The primary analysis is by intention-to-treat and uses a two-sided Mann-Whitney U test, with the Hodges-Lehmann estimate of median difference and 95% confidence interval reported alongside rank-biserial correlation and epsilon-squared for comparability with the pilot. A per-protocol sensitivity analysis excludes major deviations. A primary outcome missing because of discontinuation before the nerve block is handled by worst-case imputation, with best-case imputation as a secondary sensitivity analysis. Secondary analyses are presented without multiplicity correction and interpreted as supportive rather than confirmatory. Blinding integrity is quantified using the James index reported overall and the Bang index reported separately for each arm; these analyses are descriptive and do not modify the primary analysis. A separate statistical analysis plan is locked before database lock and unblinding.
7,046 studies on the registry are indexed under Prostatic Neoplasms; 1,580 are open to participants now.
This study's planned enrollment of 140 is above the median of 60 across 5,348 interventional studies indexed under Prostatic Neoplasms.
Browse Prostatic Neoplasms studies →Medical University of Gdansk is the lead sponsor of 133 studies on the registry; 46 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receive active transcutaneous electrical nerve stimulation (TENS) initiated 3-5 minutes before local anaesthesia, using Cefar Rehab X2 device (Class II, Type BF). Parameters: symmetrical biphasic compensated pulse, 80 Hz, 180 µs pulse duration, amplitude individually titrated to highest comfortably tolerable level. Two 5x5 cm electrodes placed in the perineal region. TENS continued throughout all procedural stages and discontinued after biopsy sampling. Standard local anaesthesia administered to all participants: 10 mL 2% lignocaine gel transrectally, followed by 20 mL 1% lignocaine using full needle-path infiltration technique.
Device: Transcutaneous Electrical Nerve Stimulation (TENS)
Participants receive sham TENS. Electrodes placed identically to the active group. Device activated in identical manner but delivers no electrical current. Device display not visible to participant; device produces no sound. Standard local anaesthesia identical to active group.
Device: Sham Transcutaneous Electrical Nerve Stimulation
Cefar Rehab X2 device (Class II, Type BF). Symmetrical biphasic compensated pulse; 80 Hz; 180 µs pulse duration; amplitude individually titrated. Two 5x5 cm electrodes in perineal region. Initiated 3-5 minutes before local anaesthesia, continued throughout procedure.
Identical electrode placement to active group. Device activated without delivering electrical current. Indistinguishable from active TENS by participant, operator, and outcome assessor.
NRS Pain Score During Periprostatic Nerve Block
Patient-reported pain intensity during periprostatic nerve block (PNB), assessed using a Numeric Rating Scale (NRS, 0-10, where 0 = no pain and 10 = worst imaginable pain). PNB consists of periprostatic infiltration ( 10 mL 1% lignocaine under real-time ultrasound guidance). The participant self-records the score on a paper form on a clipboard, within 30 seconds of the operator announcing completion of the block in fixed wording, and before the next procedural stage begins. The operator is blinded to allocation and asks no question about pain. A standardised explanation of the NRS and of the form is given to every participant before the procedure.
Time frame: Immediately after completion of periprostatic nerve block (intraoperative)
NRS Pain Score During Ultrasound Probe Insertion
NRS (0-10) assessed within 30 seconds of probe placement, before local anaesthesia administration begins.
Time frame: Immediately after ultrasound probe insertion (intraoperative)
NRS Pain Score During Perineal Infiltration
NRS (0-10) assessed within 30 seconds of completion of perineal skin and subcutaneous tissue local anaesthetic infiltration.
Time frame: Immediately after perineal infiltration (intraoperative)
NRS Pain Score During Biopsy Sampling
NRS (0-10) assessed within 30 seconds of the last biopsy core being obtained.
Time frame: Immediately after fusion-targeted biopsy sampling (intraoperative)
Procedural Safety and Tolerability
Incidence and severity of adverse events classified per Clavien-Dindo grading system.
Time frame: Through 30-day follow-up
Willingness to Repeat the Procedure
Single question (yes/no/unsure) assessing patient willingness to undergo the same procedure in the future.
Time frame: 30-day follow-up visit
Blinding Integrity - James Blinding Index
Immediately after biopsy sampling and before unblinding, the participant self-records on the same paper form which group he believes he was allocated to (active / sham / no opinion), with a certainty rating (1-5). The James blinding index is reported overall and the Bang blinding index separately for each arm, each with 95% confidence intervals.
Time frame: Immediately after biopsy sampling, before unblinding
Operator Satisfaction
Single-item Likert scale (1-5, where 1 = very dissatisfied and 5 = very satisfied with procedural conditions), recorded by the operating urologist immediately after the procedure, assessing overall satisfaction with procedural conditions during the biopsy.
Time frame: Immediately after procedure
Patient Satisfaction
Single-item Likert scale (1-5, where 1 = very dissatisfied and 5 = very satisfied), recorded immediately after procedure self-recorded by the participant on the paper form immediately after the procedure
Time frame: Immediately after procedure
Blinding Integrity - Operator
Time frame: Immediately after each procedure and before leaving the room, the operating urologist records which group he believes the participant was allocated to (active / sham / no opinion), with a certainty rating (1-5).
procedure duration
Time frame: Intraoperative, from probe insertion to last biopsy core
Preoperative state anxiety (State-Trait Anxiety Inventory - State subscale, STAI-S)
State anxiety assessed once before the procedure using the State subscale of the State-Trait Anxiety Inventory (STAI-S; Spielberger et al., 1983; validated Polish adaptation by Wrześniewski, Sosnowski, Jaworowska \& Fecenec, Pracownia Testów Psychologicznych). The STAI-S comprises 20 items rated 1-4; total score ranges from 20 to 80, with higher scores indicating greater state anxiety. Reported as the mean score per arm.
Time frame: Administered before the procedure.
NRS-Anxiety
NRS-Anxiety (0-10; single item: "How anxious are you right now?"). Administered before the procedure and immediately after biopsy sampling to assess pre-to-post procedural anxiety change. Pre-to-post delta reported as exploratory outcome.
Time frame: Administered before the procedure and immediately after biopsy sampling to assess pre-to-post procedural anxiety change.
Pain Catastrophizing Scale (PCS-13)
Pain Catastrophizing Scale (Sullivan et al., Psychol Assess 1995;7:524-532). 13-item self-report questionnaire, score 0-52. Three subscales: rumination, magnification, helplessness. Polish version available. Administered before the procedure as covariate for primary outcome analysis.
Time frame: Before the procedure
TENS Amplitude vs Pain Reduction
Actual TENS amplitude used (mA) recorded for each participant in the active group. Spearman correlation between amplitude and NRS reduction during PNB.
Time frame: Intraoperative (active group only)
Change in single-item anxiety (NRS-anxiety, 0-10) from baseline (pre-procedure) to immediately post-procedure
Procedural anxiety measured with a single-item numeric rating scale (NRS-anxiety: "How anxious are you right now?"; 0 = not at all anxious, 10 = the most anxious imaginable). Assessed at two time points: immediately before the procedure (baseline) and immediately after completion of biopsy sampling. The pre-to-post change (post minus baseline; range -10 to +10, with negative values indicating reduced anxiety) is the reported metric and is compared between the TENS and sham-TENS arms. Reported as the mean change per arm.
Time frame: Baseline (immediately before the procedure) and immediately after completion of biopsy sampling (Day 0)
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: Yes — De-identified individual participant data underlying the results reported in the primary publication will be made publicly available at the Open Science Framework (OSF) at the time of publication.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Analytic code
Time frame: Beginning at time of publication, no end date.
Access criteria: Publicly available without restriction via Open Science Framework (OSF).
Data sharing details ↗ · osf.io
Started Aug 2026 (actual). Primary completion is estimated for Apr 2027, 8 months after the start.
Of 1,098 non-industry interventional studies with no phase under Prostatic Neoplasms, half reached primary completion within 43 months of starting (the median), counting those still running; a quarter within 22 and three quarters within 86. This study's planned 8 months is below that.
Counting every sponsor, half of 1,155 studies reached it within 43 months; a quarter within 22 and three quarters within 84.
How these figures are worked out, and which studies are left out of them.
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