Focal Laser Ablation in Prostate Cancer

Prostate cancer (PCa) is the second most common neoplasm diagnosed in men with an estimated 1.4 million diagnoses and 375,000 deaths worldwide in 2020.

For localized prostate cancer (PCa), active surveillance (AS) or whole gland treatment (ie, radical prostatectomy [RP] and radiotherapy) are considered standard treatment options. Unfortunately, treatment-related morbidity is high.

The ProtecT trial showed urinary incontinence rates of 3% and 20% and erectile dysfunction rates of 66% and 79% for radiotherapy and radical prostatectomy, respectively. Radiotherapy can also cause rectal problems with a small increased risk of radiotherapy-induced secondary malignancy.

Consequently, over the past few years, there has been a notable escalation in scholarly attention towards the implementation of focal therapeutic interventions for patients diagnosed with low- and intermediate-risk prostate cancer (PCa).

This tissue-preserving strategy has at its core the reduction of treatment-related toxicity by minimizing damage caused to the prostate and adjacent structures while attempting to retain the benefits of treating cancer.

The rationale of focal therapy (FT) is based on the theory that the largest lesion with the highest grade, the so-called "index lesion," determines the risk of metastases and thus the patient's prognosis.

FT involves ablating only the index lesion, thereby minimizing damage to collateral tissue such as neurovascular bundles, external urinary sphincter, bladder neck and rectum.

Over the past few years, different types of energy sources in FT have been studied. These consist of high-intensity focused ultrasound (HIFU), irreversible electroporation (IRE), cryotherapy, photodynamic therapy (PDT), focal laser ablation (FLA) or laser interstitial thermotherapy, radiofrequency ablation (RFA), and focal brachytherapy.

According to the European Association of Urology (EAU), low-risk and intermediate-risk patients may undergo local procedures using HIFU or cryotherapy within clinical trials or registries, with the aim of achieving long-term cancer control and reducing morbidity associated with surgery and radiation therapy.

Many groups have published limited data on outcomes following in-bore MRI-guided focal therapy, and many others are actively engaged or considering prospective comparative effectiveness research in this area.

The primary objective encompasses a thorough evaluation of the short-term oncological & functional outcomes of MRI-US or PSMA PET/CT-U/S fusion-guided focal laser ablation (FLA) for the treatment of a small, localized, intermediate-risk prostate cancer.

Concurrently, the secondary aim involves an assessment of the utility of multiparametric magnetic resonance imaging (mpMRI) as a diagnostic pre-treatment tool and during the post-treatment follow-up to examine the morphostructural alterations in the prostate gland resulting from FLA. Additionally, the investigatirs aim to assess its reproducibility in determining the response to FLA therapy, correlating these findings with biopsy results, with the ultimate objective of establishing its predictive diagnostic value in identifying residual or recurring tumors.

Inclusion criteria

• Prostate cancer visible on mpMRI or PSMA PET/CT and positive in the targeted biopsy.
• Gleason score 7 (ISUP grade 2/3)
• PSA 10-20 ng/mL
• Clinical stage T2b
• Refusing radical prostatectomy.

Exclusion criteria

• Prostate cancer invisible on mpMRI or PSMA PET/CT but positive in the systematic biopsies.
• Presence of >2 MRI-visible lesions and positive in the biopsies.
• Extracapsular extension
• Seminal vesicle invasion
• Presence of metastases detected by imaging
• Gleason Score > 7
• Stage > T2b
• PSA > 20 ng/mL
• Urinary tract infection (UTI)
• Severe lower urinary tract symptoms defined as an IPSS >20
• Severe coagulation disorders
• Inadequate compliance
• Contraindications to MRI
• Paramagnetic contrast agent allergy
• Acute and/or chronic renal failure