Radiation Therapy in Treating Patients With Prostate Cancer

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