\*Rationale : Active surveillance of prostate cancer helps to avoid the morbidity associated with curative radical prostatectomy /radiotherapy in patients with early stage disease. However, at 5 years and 15 years, respectively 35 % and nearly 50 % of patients require rescue interventional treatments. Numerous Phase II trials have reported using focal treatments (focused on the macroscopic tumor only while not involving the whole prostatic gland) in order to reduce the morbidity due to recurrence as well as the high anxiety rates under observation only. Stereotactic radiotherapy (highly focused radiotherapy technic to reduce the risk of side effects) is being proposed in the same way as it does not require any anaesthesia, as opposed to all the other focal methods. The purpose of this trial is to evaluate whether focal stereotactic radiotherapy treatments could reduce the rate of rescue treatments among patients eligible to an active surveillance program at first.
* Major Inclusion Criteria :
* 1\. Early stage prostate adenocarcinoma (CAPRA score ≤ 5) * 2\. No major urinary problems * 3\. Active Surveillance possible * Major Exclusion Criteria :
* 1\. Age at diagnosis \< 50 years * 8\. Androgen-deprivation therapy * 9\. Any cancer within the last 5 years except skin basocellular carcinoma or any uncontrolled cancer * Trial : Phase II randomized trial comparing Stereotactic Radiation Therapy focused on the macroscopic tumor or Active Surveillance as the control arm. * Main objective : to compare the rescue treatment rates between the two arms
a. Localized prostate adenocarcinoma CAPRA score ≤ 5. This lesion is considered the Index lesion
b. Macroscopic tumor PIRADS score >4 on multiparametric MRI
c. The biopsies must be pathologic in or in the direct vicinity (the same prostatic zone defined as a quarter volume of the prostate (PZ)) of the MRI pathologic nodule
d. The absence of MRI pathologic criteria (PIRADS ≤3) in a Gleason score ≤ 6 (3+3)-ISUP Grade1 zone outside of the single Index lesion is considered clinically non-significant and does not preclude inclusion
a. Age at diagnosis < 50 years
b. Time between initial diagnostic biopsies and randomization > 4 months, or radiation therapy initiation > 6 months
c. Cribriform or Intraductal histologic components
d. Gleason Score ≥7 (3+4)-ISUP Grade 2 biopsy outside the intent to treat PZ