Trans-rectal Focal Microwave Ablation of the Index Tumor in Patients With Low-risk Prostate Cancer

Inclusion Criteria:

* Patients aged from 45 to 76 years old ;
* Life expectancy above 10 years ;
* Diagnosis of prostate cancer confirmed on prostate biopsies ;
* Low risk of progression, defined with D'Amico criteria :

  * T1c or T2a stage
  * Maximum Gleason score of 3+4, including targeted biopsies corresponding to less than 50% grade 4 for the tumor
  * Prostate Specific Antigen \<15 ng/mL
* Detection of the index tumor with prostate MRI, characterized with targeted biopsies using MRI-transrectal ultrasound image registration ;
* Patient accepting to be followed after the procedure using active surveillance protocol standards ;
* Patient affiliated to national health care insurance ;
* Free consent, informed and written, dated and signed by the patient and the investigator before enrollment.

Exclusion Criteria:

* Medical past history of prostatic surgery ;
* Medical past history of radiotherapy or pelvic trauma ;
* Medical past history of acute or chronic prostatitis
* severe BPH-related urinary tract symptoms defined as an IPSS \>18 ;
* Extra-capsular extension or seminal vesicle invasion on prostate MRI.
* Tumor involvement \> 3 mm on systematic biopsies outside the tumor volume detected on MRI.
* Tumor largest axis \> 20 mm on prostate MRI ;
* Distance of less than 5 mm between the tumor and the rectum
* Patient unable to understand the course of the study
* History of allergy or non-tolerance to gadolinium salts used in MRI
* Patient with a contraindication to performing an MRI
* Person placed under safeguard of justice