Hormone Therapy and Intensity-Modulated Radiation Therapy in Treating Patients With Metastatic Prostate Cancer

Inclusion Criteria:

* Patients with histologically proven diagnosis of adenocarcinoma of the prostate stage N1, N2, N3, M1a, M1b, M1c with =\< 5 metastatic lesions; if the diagnosis of metastasis in the lymph node is based solely on imaging computed tomography (CT) scan or magnetic resonance imaging (MRI), the longitudinal diameter of the lymph node has to be \>= 2.0 cm; if the lymph node is positive on positron emission tomography (PET) or ProstaScint scan, the longitudinal diameter of the lymph node on CT scan or MRI has to be \>= 1.5 cm
* Patients who have measurable disease must have had X-rays, scans or physical examination used for tumor measurement completed within 28 days prior to registration; patients must have non-measurable disease assessed within 42 days prior to registration
* Patients must have had documented PSA of \> 2 prior to onset of androgen deprivation
* Patients might have received up to 36 weeks of adjuvant androgen deprivation therapy and up to 36 weeks of androgen deprivation therapy for metastatic disease prior to enrollment to this study; patients may be on androgen deprivation for metastatic disease at the time of enrollment to the protocol; adjuvant therapy must have been completed at least 2 years before androgen deprivation for metastatic disease and patients must remain hormone sensitive
* Prior radiation therapy for metastatic disease is not allowed
* Prior chemotherapy for metastatic disease is not allowed; prior neoadjuvant and adjuvant chemotherapy is allowed; patients must have recovered from all acute side-effects related to previous systemic therapy
* Patients are allowed to receive one prior systemic non-chemotherapeutic treatment (i. e. immunotherapy, receptor tyrosine kinase inhibitor, antiangiogenic agent, differentiation agent) for recurrent or metastatic disease; patients must have recovered from all acute side-effects related to previous systemic therapy
* Use of bisphosphonates is allowed at the discretion of treating physician
* Patients must be capable of understanding the nature of the trial and must give written informed consent
* Patients must have a World Health Organization (WHO) performance status of 0, 1, or 2

Exclusion Criteria:

* Patients with unstable or severe intercurrent medical conditions or active, uncontrolled infection
* Patients with a history of orchiectomy
* Patients undergoing therapy with other investigational agents; patients must have recovered from all acute effects of previously administered investigational agents and sufficient time must have elapsed since last administration to ensure the drug interactions not occur during this study
* Patients with a history of brain metastases or who currently have treated or untreated brain metastases
* Patients who have demonstrated refractoriness to hormone therapy with luteinizing hormone-releasing hormone (LHRH) agonist; refractoriness is defined as occurrence of one of the following while on therapy with LHRH agonist: increase in PSA by 25% over baseline (to at least \> 2 ng/ml) on two consecutive PSA measurements, 20% increase in the sum of longest diameters of target measurable lesions over smallest sum observed (over baseline if no decrease during therapy) using the same techniques as baseline, clear worsening of any non-measurable disease, reappearance of any lesion that had disappeared, appearance of any new lesion