Comparison of High-Dose Rate Brachytherapy and Stereotactic Ablative Radiotherapy as Monotherapy for the Treatment of Localized Prostate Cancer

Inclusion Criteria:

* Histologically confirmed adenocarcinoma of the prostate diagnosed within the last 9 months. Patients on active surveillance with evidence of disease progression are eligible to the protocol as long as they meet the eligibility criteria and have a recent prostate biopsy (within 9 months)
* Low-risk and intermediate-risk patients are eligible according to the following guidelines:

  * Low and intermediate-risk disease defined as:

    * Clinical stage T1-T2 and Gleason =\< 7 and prostate specific antigen (PSA) \< 15 ng/ml
* Lymph node evaluation by either computed tomography (CT) or magnetic resonance imaging (MRI) and bone scan are optional and are left at the discretion of the treating physician
* Prostate MRI is recommended by not mandatory
* No alpha reductase inhibitors use within 2 weeks of randomization. A washout period of 2 weeks is required prior to randomization
* Eastern Cooperative Oncology Group status 0-1
* Judged to be medically fit for brachytherapy by a radiation oncologist
* Concurrent, neoadjuvant and/or adjuvant androgen deprivation therapy (ADT) is not permitted
* Prostate volume by trans-rectal ultrasound (TRUS) =\< 60 cc
* International Prognostic Scoring System (IPSS) =\< 20 (alpha blockers allowed)
* Patients must sign a study specific informed consent form prior to study entry
* Patients must by accessible for treatment and follow-up. Patients registered on this trial must be treated and followed at the participating center. Investigators must assure themselves that patients enrolled in this trial will be available for complete documentation of the treatment, adverse events, and follow up
* Protocol treatment is to begin within 4 weeks of patient randomization

Exclusion Criteria:

* Patients with a history of other malignancies, except: adequately treated non-melanoma skin cancer, or other solid tumors curatively treated with no evidence of disease for \>= 5 years
* Prior or current bleeding diathesis
* Radical surgery for carcinoma of the prostate, prior pelvic radiation, prior chemotherapy for prostate cancer, prior transurethral resection of the prostate (TURP), prior cryosurgery of the prostate
* Stage T3b and evidence of nodal or distant metastatic disease on diagnostic CT, MRI or bone scan
* Subjects who have plans to receive other concomitant or post treatment adjuvant antineoplastic therapy while on this protocol including surgery, cryotherapy, conventionally fractionated radiotherapy, hormonal therapy, or chemotherapy given as part of the treatment of prostate cancer
* 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 for 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 within 30 days before registration
  * Hepatic insufficiency resulting in clinical jaundice and/or coagulations defects; note, however, that laboratory tests for liver function and coagulation parameters are not required for entry into this protocol
  * Acquired immune deficiency syndrome (AIDS) based upon current Centers for Disease Control and Prevention (CDC) definition; note, however, that human immunodeficiency virus (HIV) testing is not required for entry into this protocol. The need to exclude patients with AIDS from this protocol is necessary because the treatments involved in this protocol may be significantly immunosuppressive. Protocol-specific requirements may also exclude immumo-compromised patients
  * Patients with history of inflammatory colitis (including Crohn's disease and ulcerative colitis) or collagen vascular diseases including rheumatoid arthritis and lupus are not eligible
* Subjects who have a history of significant psychiatric illness
* Men of reproductive potential who do not agree that they or their partner will use an effective contraceptive method such as condom/diaphragm and spermicidal foam, intrauterine device (IUD), or prescription birth control pills