Radiation Therapy in Treating Patients With Prostate Cancer

RATIONALE: Radiation therapy uses high-energy x-rays to kill tumor cells. Specialized radiation therapy that delivers a high dose of radiation directly to the tumor may kill more tumor cells and cause less damage to normal tissue. Given radiation therapy in different ways may kill more tumor cells.

PURPOSE: This randomized phase II trial studies radiation therapy to see how well it works in treating patients with prostate cancer.

OBJECTIVES:

Primary

* To demonstrate that 1-year health-related quality of life (HRQOL) for at least one hypofractionated arm is not significantly lower than baseline as measured by the Bowel and Urinary domains of the Expanded Prostate Cancer Index Composite (EPIC) instrument.

Secondary

* To estimate the degree of change in HRQOL in each arm for the Sexual and Hormonal EPIC domains and the Utilization of Sexual Medications/Devices from baseline to 1 year, 2 years, and 5 years.
* To estimate the degree of change in global HRQOL in each arm as measured by the Euro Quality of Life, 5 dimensions (EQ-5D) from baseline to 1 year, 2 years, and 5 years.
* To estimate the rate of acute and late gastrointestinal (GI) and genitourinary (GU) toxicity for each arm at 1, 2, and 5 years.
* To estimate prostate-specific antigen (PSA) failure in each arm at 1, 2, and 5 years.
* To estimate disease-free survival (DFS) in each arm at 1, 2, and 5 years.
* To estimate Quality Adjusted Life Years for each arm at 1, 2, and 5 years using the EQ-5D and DFS.
* To identify genetic markers associated with normal tissue toxicities resulting from radiotherapy.
* To collect tumor tissue for biomarker studies.
* To estimate EPIC bowel and urinary HRQOL as continuous variables.

OUTLINE: This is a multicenter study. Patients are stratified according to treatment techniques/machine (all linear accelerator-based treatment \[excluding cyberknife\] vs cyberknife vs protons). Patients are randomized to 1 of 2 treatment arms.

* Arm I: Patients undergo hypofractionated radiotherapy using intensity-modulated radiation therapy (IMRT), cyberknife, or protons twice a week for approximately 2½ weeks (36.25 Gy total).
* Arm II: Patients undergo hypofractionated radiotherapy using IMRT, cyberknife, or protons once a day, 5 days a week, for approximately 2½ weeks (51.6 Gy total).

Patients may undergo blood and tumor tissue collection for correlative studies.

Patients may also complete the Utilization of Sexual Medications/Devices, the European Questionnaire-5D, and the Bowel and Urinary domains of the Expanded Prostate Cancer Index Composite (EPIC) questionnaires at baseline and at 1, 2, and 5 years after completion of radiation therapy.

After completion of study therapy, patients are followed-up every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter.

Eligibility Criteria:
DISEASE CHARACTERISTICS:

* Histologically confirmed diagnosis of adenocarcinoma of the prostate within 180 days of randomization

  * History/physical examination with digital rectal examination of the prostate within 60 days prior to registration
  * Histological evaluation of prostate biopsy with assignment of a Gleason score to the biopsy material; Gleason scores 2-6 within 180 days of randomization
  * Clinical stage T1-2a (AJCC 7th edition) within 90 days of randomization
  * Prostate-specific antigen (PSA) \< 10 ng/mL within 60 days prior to registration;

    * PSA should not be obtained within 10 days after prostate biopsy
* No evidence of distant metastases
* No regional lymph node involvement

PATIENT CHARACTERISTICS:

* Zubrod performance status 0-1
* Willingness and ability to complete the Expanded Prostate Cancer Index Composite (EPIC) questionnaire
* No prior or concurrent invasive malignancy (except non-melanomatous skin cancer) or lymphomatous/hematogenous malignancy unless continually disease-free for a minimum of 5 years (for example, carcinoma of the oral cavity is permissible; however, patients with prior history of bladder cancer are not allowed)
* No severe, active co-morbidity, defined as follows:

  * Unstable angina and/or congestive heart failure requiring hospitalization within the last 6 months
  * Transmural myocardial infarction within the last 6 months
  * Acute bacterial or fungal infection requiring intravenous antibiotics at the time of registration
  * Chronic obstructive pulmonary disease exacerbation or other respiratory illness requiring hospitalization or precluding study therapy at the time of registration
  * Hepatic insufficiency resulting in clinical jaundice and/or coagulation defects

    * Laboratory tests for liver function and coagulation parameters are not required for entry into this protocol
  * Acquired Immune Deficiency Syndrome (AIDS) based upon current Center for Disease Control (CDC) definition

    * HIV testing is not required for entry into this protocol
    * Protocol-specific requirements may also exclude immuno-compromised patients

PRIOR CONCURRENT THERAPY:

* No prior radical surgery (prostatectomy), cryosurgery, or high-intensity focused ultrasonography (HIFU) for prostate cancer
* No prior pelvic irradiation, prostate brachytherapy, or bilateral orchiectomy
* No prior hormonal therapy, such as luteinizing hormone-releasing hormone (LHRH) agonists (e.g., goserelin, leuprolide) or LHRH antagonists (e.g., degarelix), anti-androgens (e.g., flutamide, bicalutamide), estrogens (e.g., diethylstilbestrol (DES)), or surgical castration (orchiectomy)
* No finasteride within 30 days prior to registration

  * Prostate-specific antigen (PSA) should not be obtained prior to 30 days after stopping finasteride
* No dutasteride within 90 days prior to registration

  * PSA should not be obtained prior to 90 days after stopping dutasteride
* No prior or concurrent cytotoxic chemotherapy for prostate cancer
* Patients on Coumadin or other blood-thinning agents are eligible for this study
* No concurrent 3D-conformal radiation therapy