Irreversible Electroporation (IRE), used in prostate cancer treatment, stands out as a minimally invasive method. Also known as NanoKnife, this technique destroys cancer cells with high‑voltage electrical pulses. However, it does not harm healthy tissues such as nerves and blood vessels. It is especially applied in patients with localized prostate cancer and intermediate‑risk tumors confined to a single lobe of the prostate. Moreover, it has been shown to have fewer side effects such as incontinence and impotence compared to surgery and radiotherapy. Nonetheless, more data on recurrence and long‑term outcomes are needed.
| Treatment Method | Irreversible Electroporation (IRE) – NanoKnife |
| Definition | A minimally invasive treatment in prostate cancer that uses high‑voltage electrical currents to increase the permeability of cancer cell membranes, causing cell death. |
| Applications | Early‑stage prostate cancer, small and localized tumors, patients unsuitable for or declining surgery or radiotherapy. |
| Advantages | Effectively targets the tumor region while causing minimal damage to surrounding nerves, vessels, and tissues; provides an advantage in preserving urinary continence and sexual function. |
| Procedure | Under general anesthesia and guided by ultrasound or MRI, thin electrodes are placed into the tumor region; electrical pulses are delivered to cancer cells. The procedure typically lasts 1–2 hours. |
| Side Effects | Temporary pain after the procedure, risk of urinary tract infection, rarely difficulty urinating, tenderness at the treatment site; serious side effects are rare. |
| Success Rate | High success rate in early‑stage and localized tumors; varies depending on tumor size and location. |
| Follow‑Up | Regular monitoring of prostate‑specific antigen (PSA) levels post‑procedure, MRI or biopsy to assess treatment response. |
| Alternative Methods | Radical prostatectomy, radiotherapy, focal ablation methods (cryotherapy, HIFU). |
| Related Conditions | Prostate cancer, low‑ and intermediate‑risk localized prostate tumors. |
| Precautions | Pre‑procedure antibiotic use is recommended to reduce infection risk; the patient’s PSA and MRI results are considered in planning the procedure. |
Interventional Radiology / Interventional Neuroradiology
Prof. Dr. Özgür KILIÇKESMEZ
What Is Irreversible Electroporation (IRE) and How Does NanoKnife Work?
Irreversible Electroporation (IRE), also known as NanoKnife, is used as a minimally invasive method in prostate cancer and operates as a non‑thermal ablation technique. This technique delivers high‑voltage electrical pulses that disrupt the membrane structure of cancer cells, leading to loss of cellular homeostasis. The main advantage of IRE is that it offers a safe treatment option in areas with sensitive structures such as nerves and blood vessels by preserving healthy tissues.
The NanoKnife device transmits electrical pulses directly to the tumor via electrodes placed around the target. These pulses irreversibly damage cell membranes, initiating apoptosis. Thus, inflammation and collateral damage to surrounding tissues are minimized.
- Difference from Cryotherapy: IRE destroys cancer cells using electricity rather than cold. Cryotherapy freezes tumors but carries the risk that blood flow may counteract the freezing effect.
- Difference from High‑Intensity Focused Ultrasound (HIFU): IRE does not rely on thermal mechanisms. This makes it a safe option in regions where heat‑based techniques like HIFU could harm delicate structures.
Who Is a Candidate for NanoKnife in Prostate Cancer?
NanoKnife treatment is suitable for certain patient groups in prostate cancer. Ideal candidates are typically men with localized prostate cancer who wish to avoid the significant side effects of traditional methods like surgery or radiotherapy. Cases with low to intermediate‑risk tumors confined to one lobe of the prostate show successful results with NanoKnife.
Especially, the following patients are considered ideal candidates:
- Patients with clinical stage ≤ T2c prostate cancer
- Patients with Gleason score 3+4 or 4+3
- Those with PSA level ≤ 15 ng/mL
Additionally, NanoKnife usually reduces the risk of side effects compared to radical prostatectomy or radiotherapy, making it suitable for men who want to maintain quality of life. Patients aiming to preserve urinary control and sexual function see NanoKnife as a safe option. Older men with comorbidities who are not surgical candidates also benefit. Patients with prior radiotherapy failure seeking salvage treatment are recommended NanoKnife. Conversely, those with metastatic disease or Gleason score ≥ 8 are not suitable and should pursue more aggressive treatments.
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How Effective Is the NanoKnife Procedure in Treating Prostate Cancer?
NanoKnife stands out for various advantages in prostate cancer treatment but also entails some risks.
Benefits:
- Minimal Side Effects: As a non‑thermal method, NanoKnife operates without harming adjacent tissues, preserving urinary and sexual functions compared to surgery or radiotherapy.
- Function Preservation: Protects nerves around the prostate, maintaining continence and erectile capability, offering a significant advantage over radical prostatectomy or radiotherapy.
- Rapid Recovery: Being minimally invasive, patients are typically discharged the same day and can quickly resume daily life, with only short‑term catheter use required.
- Targeted Treatment: Effectively reaches tumors in hard‑to‑access areas without damaging vital structures like the urethral sphincter.
Risks:
- Cancer Recurrence: Although initial treatment may be successful, there is a recurrence risk; 15–30% of patients may need retreatment within five years, requiring continuous follow‑up.
- Experimental Status: Long‑term efficacy data are limited. Therefore, it is generally recommended for specific patient profiles while long‑term outcome studies continue.
What Is the Long‑Term Outlook for Patients Treated with NanoKnife?
The long‑term outlook for prostate cancer patients treated with NanoKnife is promising, and regular follow‑up is crucial to ensure treatment success. The IRE method ablates cancerous tissue while preserving surrounding nerves and connective tissues, reducing side effect risks. Post‑treatment monitoring enables timely detection of potential recurrences.
Follow‑up measures include:
- PSA Testing: PSA levels are monitored every three months post‑treatment; rising PSA may indicate recurrence.
- MRI Imaging: Multiparametric MRI scans every six months are necessary for early detection of cancerous lesions. MRI provides detailed visualization of residual or new cancerous tissue.
- Biopsy: Performed when PSA levels rise or MRI findings are suspicious to confirm recurrence.
In terms of long‑term effectiveness, IRE generally achieves 90–97% disease‑free survival. However, recurrence rates can reach up to 15% in subsequent years. In such cases, repeat focal ablation or other minimally invasive treatments may be preferred. NanoKnife shows promise in reducing recurrence rates and providing more durable success.
Prof. Dr. Özgür Kılıçkesmez graduated from Cerrahpaşa Medical Faculty in 1997. He completed his specialization at Istanbul Education and Research Hospital. He received training in interventional radiology and oncology in London. He founded the interventional radiology department at Istanbul Çam and Sakura City Hospital and became a professor in 2020. He holds many international awards and certificates, has over 150 scientific publications, and has been cited more than 1500 times. He is currently working at Medicana Ataköy Hospital.
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