Inclusion Criteria:

          -  PRE-REGISTRATION INCLUSION (STEP 0)

          -  Patient must have undergone a radical prostatectomy (RP) and must be registered to
             step 0 of this study at least 6 weeks after but not more than 16 weeks after their
             radical prostatectomy

          -  Patient must have an Eastern Cooperative Oncology Group (ECOG) performance status of
             0- 2

          -  Patient with a prior or concurrent malignancy within 5 years of registration, whose
             natural history or treatment does not have the potential to interfere with the safety
             or efficacy assessment of the investigational regimen are eligible for this trial

          -  Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral
             therapy with undetectable viral load within 6 months are eligible for this trial

          -  For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral
             load must be undetectable on suppressive therapy, if indicated

          -  Patients with a history of hepatitis C virus (HCV) infection must have been treated
             and cured. For patients with HCV infection who are currently on treatment, they are
             eligible if they have an undetectable HCV viral load

          -  For patients with no previous Decipher score: Tumor tissue specimen from prostatectomy
             must be available and ready to be shipped

          -  INCLUSION CRITERIA FOR RANDOMIZATION (STEP 1)

          -  For patients who have previously had Decipher score performed by Decipher Biosciences,
             they must have score of >= 0.6

          -  For patients who did not have a Decipher score previously performed by Decipher
             Biosciences, they must have had a Decipher score of >= 0.6 assessed from the
             prostatectomy specimen submitted

          -  For patients who did not have a Decipher score previously performed by Decipher
             Biosciences, patients must also have a CAPRA-S score >= 3. The CAPRA-S score is
             calculated by assigning points for PSA in ng/mL, surgical margin status, seminal
             vesicle invasion, and extra-capsular extension. Lymph node involvement will serve as
             an exclusion criteria and will not count towards CAPRA-S inclusion score. A CAPRA-S
             score is not required for patients who had a Decipher score previously performed by
             Decipher Biosciences

          -  Patient must have an undetectable PSA (< 0.2ng/mL) obtained within 2 weeks prior to
             randomization

          -  Leukocytes >= 3,000/mcL (obtained within 4 weeks prior to registration)

          -  Absolute neutrophil count >= 1,000/mcL (obtained within 4 weeks prior to registration)

          -  Platelets >= 75,000/mcL (obtained within 4 weeks prior to registration)

          -  Total bilirubin =< institutional upper limit of normal (ULN) (obtained within 4 weeks
             prior to registration)

          -  Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase
             [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT])
             =< 2.5 x institutional ULN (obtained within 4 weeks prior to registration)

          -  Glomerular filtration rate (GFR) >= 30 mL/min/1.73 m^2 (obtained within 4 weeks prior
             to registration)

        Exclusion Criteria:

          -  PRE-REGISTRATION EXCLUSION (STEP 0)

          -  Patient must not have any previous treatment with androgen deprivation therapy (ADT),
             chemotherapy, or other physician prescribed systemic therapy for treatment of their
             prostate cancer

          -  Patient must not have pathologic evidence of pelvic lymph node involvement

          -  Patient must not have an uncontrolled intercurrent illness including, but not limited
             to, ongoing or active infection, symptomatic congestive heart failure (New York Heart
             Association class III and IV heart failure), unstable angina pectoris, cardiac
             arrhythmia, or psychiatric illness/social situations that would limit compliance with
             study requirements

          -  EXCLUSION CRITERIA FOR RANDOMIZATION (STEP 1)

          -  Patient must not have pre or post-operative radiographic evidence of cancer recurrence
             or metastasis by abdominal and pelvic imaging (computed tomography [CT]
             abdomen/pelvis, whole body magnetic resonance imaging [MRI], MRI abdomen/pelvis, or
             equivalent, AND bone scan) which must be done before or after prostatectomy prior to
             randomization. If pre-operative risk does not indicate a need for bone scan,
             post-operative Decipher score of >= 0.6 indicates increased risk of metastatic disease
             and may be used to obtain CT abdomen/pelvis and bone scan prior to randomization