NanoKnife, medically referred to as irreversible electroporation (IRE), is an emerging focal therapy for selected men with localized prostate cancer. By 2026, it has gained increasing attention as a treatment that aims to control cancer while preserving quality of life. Unlike surgery or radiation, NanoKnife does not remove or irradiate the entire prostate. Instead, it selectively destroys cancerous tissue using short, high-voltage electrical pulses, leaving surrounding structures such as nerves, blood vessels, and the urethra largely intact.
For patients trying to understand whether NanoKnife is effective, the key question is not simply “Does it work?” but rather what the NanoKnife success rate for prostate cancer truly represents, how success is measured, and which patients are most likely to benefit from this approach. The concept of success with focal therapy differs from traditional whole-gland treatments and must be interpreted in the context of cancer control, functional outcomes, and the need for additional therapy over time.
This article reviews the NanoKnife success rate for prostate cancer using the best available clinical evidence and explains what these outcomes realistically mean for patients considering this treatment option in 2026.
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Understanding NanoKnife (Irreversible Electroporation)
NanoKnife works by delivering short, high-voltage electrical pulses through thin needle electrodes placed directly into the prostate under imaging guidance, usually MRI–ultrasound fusion. These electrical fields create permanent nanopores in cancer cell membranes, leading to programmed cell death. Importantly, this process is non-thermal, meaning it does not rely on heat or freezing (Scheffer et al., Journal of Urology, 2017).
Because connective tissue, blood vessels, nerves, and the urethra are relatively resistant to this electrical injury, NanoKnife can treat tumors located near critical structures with less risk of functional damage than thermal ablation, surgery, or radiation (van den Bos et al., European Urology, 2018).
What Does “Success Rate” Mean in NanoKnife Therapy?
Success in NanoKnife treatment is fundamentally different from success after radical prostatectomy or whole-gland radiation. Since the prostate is preserved, outcomes are evaluated using multiple criteria rather than a single endpoint.
Clinically, NanoKnife success is assessed by:
- Absence of clinically significant cancer in the treated zone on follow-up biopsy
- Stable or decreasing prostate-specific antigen (PSA) levels
- Freedom from progression requiring radical therapy
- Preservation of urinary continence and sexual function
This multi-dimensional definition is critical for patients to understand. NanoKnife is not designed to eliminate every prostate cell, but to control cancer while minimizing harm (Valerio et al., European Urology, 2017).
Cancer Control and Tumor Eradication Rates
Short- and Medium-Term Cancer Control
Across prospective cohort studies and multicenter registries, 70–85% of men undergoing NanoKnife have no clinically significant cancer detected in the treated area on follow-up biopsy at 12 to 24 months (Blazevski et al., BJU International, 2020).
Clinically significant cancer is typically defined as Gleason grade group ≥2. When low-grade residual disease is included, detection rates are higher, but these findings often do not require immediate treatment and are instead managed with surveillance.
Local Recurrence Rates
Local recurrence within the treated field occurs in approximately 10–30% of patients, depending on tumor characteristics and follow-up duration. Higher recurrence rates are observed in patients with larger lesions, higher-grade disease, or suboptimal lesion targeting on imaging (Murray et al., Prostate Cancer and Prostatic Diseases, 2021).
Importantly, most recurrences are detected early and remain localized, allowing retreatment with focal therapy, surgery, or radiation without compromising long-term outcomes.
Progression-Free and Metastasis-Free Survival
Longer-term outcome data are increasingly available. A large European multicenter analysis reported 5-year progression-free survival of approximately 75–80%, defined as avoidance of radical whole-gland treatment or high-grade progression (van den Bos et al., European Urology Oncology, 2022).
Even more reassuring for patients, metastasis-free survival consistently exceeds 95% in published series. This suggests that while local recurrence may occur, NanoKnife does not appear to increase the risk of systemic spread when patients are appropriately selected and monitored (Eldred-Evans et al., Nature Reviews Urology, 2023).
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Functional Outcomes: A Major Measure of Success
Urinary Continence
Urinary continence preservation is one of NanoKnife’s strongest advantages. Across studies, 95–99% of men remain pad-free after treatment, with very low rates of long-term urinary incontinence. Temporary urinary symptoms such as frequency or urgency may occur but usually resolve within weeks (Scheffer et al., Journal of Urology, 2017).
Sexual Function
Erectile function outcomes depend on baseline function, lesion location, and extent of ablation. Overall, 70–85% of men maintain erections sufficient for intercourse, with higher rates in men whose tumors are distant from the neurovascular bundles (Blazevski et al., BJU International, 2020).
Compared with radical prostatectomy, where erectile dysfunction rates often exceed 50%, NanoKnife offers a significant quality-of-life advantage for selected patients (Ahmed et al., The Lancet Oncology, 2019).
How NanoKnife Compares With Other Treatments
When comparing success rates, it is essential to compare appropriate endpoints.
Radical prostatectomy and radiation therapy achieve excellent long-term cancer control, with disease-specific survival above 95% for localized disease. However, these benefits come with higher rates of urinary and sexual side effects.
NanoKnife offers:
- Lower cancer eradication rates compared with whole-gland treatments
- Substantially better functional outcomes
- The ability to delay or avoid radical therapy
For many men, particularly those with low-risk or favorable intermediate-risk disease, this trade-off is acceptable and desirable (Valerio et al., European Urology, 2017).
Ideal Candidates and Factors Influencing Success
NanoKnife success is highly dependent on patient selection. Best outcomes are observed in men with:
- Localized prostate cancer (low-risk or favorable intermediate-risk)
- One or two MRI-visible lesions
- PSA typically below 15 ng/mL
- No evidence of metastasis or extracapsular extension
Patients must also commit to long-term surveillance, including PSA testing, repeat MRI, and follow-up biopsies. NanoKnife is not appropriate for men unwilling or unable to undergo close monitoring (EAU Guidelines, 2025).
Limitations and Areas of Ongoing Research
Despite encouraging results, NanoKnife has limitations. Long-term data beyond 10 years are still limited, and there is variability in technique and follow-up protocols between centers. Additionally, untreated areas of the prostate may harbor microscopic disease not detected at baseline.
For these reasons, most international guidelines consider NanoKnife an emerging or selectively recommended therapy, rather than a universal standard of care (EAU Guidelines, 2025; NCCN, 2026).
Ongoing randomized trials and registry studies are expected to clarify long-term cancer-specific survival and refine patient selection criteria over the next decade.
What Patients Should Take Away
As of 2026, NanoKnife is best understood as a cancer-controlling, quality-of-life–preserving treatment, not a guaranteed cure. Approximately three out of four patients remain free from progression requiring radical treatment at five years, while the vast majority maintain urinary continence and sexual function.
For carefully selected men who value organ preservation and are comfortable with active surveillance, NanoKnife represents a meaningful and evidence-supported option. The key to success lies in expert imaging, experienced centers, and informed shared decision-making.
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Written by Armen Gevorgyan, MD