Randomized Pilot Study of Radiosurgery for the Treatment of Non-metastatic Prostate Cancer

This is a prospective, interventional pilot study to evaluate the feasibility of randomizing patients diagnosed with prostate cancer to different treatment schemes according to their risk. Patients with a diagnosis of prostate adenocarcinoma (confirmed by biopsy), without signs of metastasis outside the pelvis in the staging study and without prior radiotherapy (RT) to the pelvic region will be recruited. The definition of risk group from the international guide National Comprehensive Cancer Network will be used. * Low risk * Favorable intermediate risk * Unfavorable intermediate risk * High risk The use of hormonal blocking will be at the discretion of each treating physician. The radiotherapy simulation will be carried out according to the institutional protocol for the treatment of prostate cancer. According to the risk group of the patients, the following randomization will be carried out: * Low / intermediate favorable risk: Patients will be randomized to receive SBRT to prostate 36.25 Gy in 5 fractions, alternate days or weekly, with VMAT (technique and 6 Mega-voltage (MV) X-rays vs to SBRT to prostate 26 Gy in 2 fractions, 1 weekly fraction, with VMAT technique and 6 Mv X-rays. The volumes to be treated, ¨Clinical target volume¨ (CTV) will be defined as the prostate, according to the consensus of the Radiation Therapy Oncology Group (RTOG). * Intermediate unfavorable risk and high risk: Patients will be randomized to receive SBRT to the prostate and seminal vesicles, 36.25 Gy in 5 fractions, alternate days or weekly, with VMAT technique and 6 MV X-rays vs SBRT to pelvis scheme of 25 Gy in 5 fractions with simultaneous integrated boost up to 36.25 to the prostate and seminal vesicles, with the same technique. * Patients with positive pelvic node: Will be randomized to moderate hypofractionated RT , completing a dose of 44 Gy in 20 fractions to the pelvis with a simultaneous integrated boost up to 54-60 Gy in 20 fractions to metastatic lymphadenopathy and prostate with seminal vesicles, completing 60 Gy to prostate and seminal vesicles or to ultra hypofractionated RT to the prostate and macroscopic lymphadenopathy to 35 and 30-35 Gy respectively and 25 Gy in 5 fractions to the elective nodal areas.