A focal treatment that uses brief electrical pulses to destroy targeted prostate tumor tissue without heat or cold, largely sparing nerves and the urine-control muscle, so most treated men keep continence and erections. It leaves the rest of the gland in place; some cancer persists or returns, so careful selection and long-term follow-up matter. Long-term durability remains uncertain. (Full Review)

Protocol

Standard Procedure

Needle-electrode ablation

Under general anesthesia with a muscle relaxant, thin needle electrodes are placed through the perineum under transrectal ultrasound and MRI-fusion guidance, bracketing the target lesion plus a margin; the device delivers electrocardiogram-synchronized high-voltage pulses.

Setting & Delivery

Single short session

Usually a single, short, often outpatient or overnight procedure performed by urologists or interventional radiologists at focal-therapy centers; delivered in one session covering the target.

Eligibility & Selection

MRI-visible localized disease

Baseline prostate-specific antigen and PSA density help define eligibility (typical thresholds PSA ≤15 ng/mL or PSA density <0.15); multiparametric MRI and targeted biopsy confirm an organ-confined, localized, MRI-visible target.

Time to effect

Ablation

Immediate

The ablation itself is immediate and permanent for the treated tissue.

PSA Response

~3–4 months

Prostate-specific antigen typically falls over the first months (median nadir around 3–4 months, with roughly a 68% reduction by 6 months).

Confirmed Success

6–18 months

Oncological success is confirmed by surveillance biopsy of the treated zone, commonly performed 6–18 months after the procedure.

Benefits

High: Preservation of urinary continence; preservation of erectile function

Medium: Short- to intermediate-term local cancer control; high overall and cancer-specific survival in selected patients; low rate of serious procedural complications

Low: Repeatability and preservation of future treatment options; role in salvage after failed radiation

Speculative: Immune-mediated anti-tumor effect

Contraindications

Cancer spread beyond the prostate (stage ≥T3 with extraprostatic extension, seminal-vesicle invasion, or any nodal/metastatic disease)

High-grade disease (Gleason ≥4+4 / grade group ≥4)

Very large or diffuse multifocal tumors (typically prostate volume >80 mL or more than one significant lesion)

Baseline PSA above eligibility (PSA >15 ng/mL with PSA density ≥0.15 ng/mL²)

MRI-invisible or poorly localized target

Uncorrectable bleeding disorder (uninterruptible anticoagulation, platelets <50 ×10⁹/L)

Unfit for general anesthesia (e.g., ASA class IV)

Key Interactions

Anticoagulants and antiplatelet drugs (warfarin, apixaban, rivaroxaban, clopidogrel)

Over-the-counter agents affecting bleeding (aspirin, ibuprofen and other NSAIDs, fish oil)

Blood-thinning supplements (high-dose fish oil, vitamin E, garlic extract, ginkgo, curcumin)

Prior or concurrent pelvic radiation

Cardiac implantable device (pacemaker or defibrillator)

Risk & Side Effects

High: In-field and out-of-field cancer recurrence; transient urinary symptoms and urinary retention

Medium: Decline in erectile function; need for retreatment or conversion to radical therapy

Low: Serious procedural complications; general anesthesia and muscle-contraction effects

Speculative: Long-term oncological failure beyond current follow-up

Monitoring

Marker	Target	Why
Prostate-specific antigen (PSA)	Sustained post-treatment nadir, typically <1–2 ng/mL with no rising trend	Tracks treatment response and possible recurrence
PSA density (PSA ÷ prostate volume)	<0.15 ng/mL² at baseline (selection threshold)	Helps select candidates and interpret PSA
Multiparametric MRI findings	No new or enlarging suspicious lesion in or outside the treated zone	Detects in-field and out-of-field recurrence
Surveillance biopsy (treated zone)	No clinically significant cancer (e.g., no Gleason ≥3+4) in-field	Confirms ablation success — the definitive endpoint

Cadence: PSA checked at about 3, 6, and 12 months, then every 6–12 months; multiparametric MRI repeated during the first year; protocol surveillance biopsy of the treated zone commonly between 6 and 18 months.

Qualitative Assessment

Urinary function: continence (pad use), flow, urgency, and resolution of any post-procedure retention
Erectile function: ability to achieve erections sufficient for intercourse compared with baseline
Recovery and energy: resolution of perineal discomfort and return to normal activity
Psychological well-being: anxiety related to ongoing surveillance and uncertainty

NanoKnife to Treat Prostate Cancer

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment