MRI-guided Focal Laser Ablation

Inclusion criteria:

* MRI visible index lesion (on T2-weighted MR imaging or diffusion weighted imaging);
* Maximum MRI visible lesion size is ≤ 15 mm large axis;
* Life expectancy at inclusion of more 10 years;
* Diagnosis of prostate cancer confirmed by targeted biopsy using TRUS-MRI fusion or in-bore MRI guided biopsies;
* Criteria of low and intermediate risk of progression and eligibility for focal therapy (clinical stage of maximum T2c, maximum biopsy Gleason score of 4 + 3 on targeted biopsies, serum prostate specific antigen \< 15 ng/ml);
* Patient accepting to be included in an active surveillance protocol at the end of the study, in accordance with the recommendations of good practice.

Exclusion criteria:

* History of prostate surgery;
* History of radiation therapy or pelvic trauma; history of proved acute or chronic prostatitis;
* History of tumor in the preceding 5 years (excluded: non-metastatic basal cell skin cancer);
* Severe urinary symptoms associated with benign hyperplasia of the prostate, and defined by an IPSS score \> 18;
* Tumor with MRI signs of extra-capsular extension or invasion of the seminal vesicles;
* Maximum cancer core length \>3 mm and/or maximum Gleason score of 3+4 on systematic biopsies outside the visible tumor area on mpMRI;
* Impossibility to obtain a valid informed consent;
* Patients unable to undergo MR imaging, including those with contra-indications;
* Contra-indications to MR guided focal laser therapy (colitis ulcerosa, rectal pathology or abdomino perineal resection);
* Metallic hip implant or any other metallic implant or device that distorts local magnetic field and compromises the quality of MR imaging;
* Patients with evidence for nodal or metastatic disease;
* Patients with an estimated Glomerular Filtration Ratio (eGFR) \< 40 mL/min/1.73 m2.