Antiandrogen Therapy and Radiation Therapy With or Without Docetaxel in Treating Patients With Prostate Cancer That Has Been Removed by Surgery

Patients post-prostatectomy with baseline Gleason \>= 7 (per prostatectomy pathology)

Baseline PSA prior to start of androgen deprivation therapy nadir \>= 0.2 ng/ml (post-operative value is never undetectable) obtained prior to step 1 registration

Baseline testosterone level obtained post-prostatectomy prior to start of androgen deprivation therapy and prior to step 1 registration

Pathologically (histologically) proven diagnosis of adenocarcinoma of the prostate as confirmed at time of prostatectomy; prostatectomy must have been performed within 365 days (1 year) prior to step 1 registrationand any type of radical prostatectomy is permitted, including retropubic, perineal, laparoscopic or robotically assisted; (please note: Prior ablative treatment for benign prostatic hypertrophy or focal high-intensity focused ultrasound therapy \[HIFU\] prior to prostatectomy is allowed)

Surgical formalin-fixed paraffin-embedded (FFPE) specimen must be available for submission to GenomeDx for genomic analysis on DECIPHER GRID platform

* Please note: If a patient already has a Decipher risk score and meets all of the other eligibility criteria, the patient is eligible to be registered; however, the Decipher risk report will need to be submitted to GenomeDx for validation

Prior androgen deprivation (luteinizing hormone-releasing hormone \[LHRH\] agonist and/or non-steroidal anti-androgen) is allowed if:

* Androgen deprivation therapy was initiated within 30 days prior to study enrollment

* Androgen deprivation therapy was given for ≤ 90 days duration prior to radical prostatectomy

* Please note: Finasteride or dutasteride must be stopped before treatment but should not determine eligibility

Pathologically lymph node negative by pelvic lymphadenectomy (pN0) or lymph node status pathologically unknown (undissected pelvic lymph nodes \[pNx\])

Any pT-stage based on American Joint Committee on Cancer 7th edition eligible; study entry will be based on the following diagnostic workup:

* History/physical examination within 60 days prior to step 1 registration

* Negative distant metastatic workup:

* A computed tomography (CT) scan of the abdomen and pelvis (with contrast \[CT without contrast is permitted if the patient is not a candidate for contrast, i.e., renal function or allergy\]) or magnetic resonance imaging (MRI) of the pelvis within 120 days prior to step 1 registration; (Please note: Lymph nodes will be considered negative (NO)if they are =\< 1.5 cm short axis);

* Bone scan within 120 days prior to step 1 registration; (please note: a sodium fluoride \[NaF\] positron emission tomography \[PET\]/CT is an acceptable substitute and if the bone scan is suspicious, a plain x-ray, CT scan, NaF PET/CT and/or MRI must be obtained to rule out metastasis; Axumin scans are not allowed for determination of eligibility \[e.g. a positive Axumin can in the setting of negative bonescan and CT does not exclude a patient from being eligible for enrollment\]).

Eastern Cooperative Oncology Group (ECOG) performance status of =\< 1 within 60 days prior to step 1 registration

Platelets \>= 100,000 cell/mm\^3 (within 60 days prior to step 1 registration based upon a complete blood count \[CBC\])

Hemoglobin \>= 10.0 g/dl (Note: The use of transfusion or other intervention to achieve hemoglobin \[Hgb\] \>= 10.0 g/dl is NOT allowed) (within 60 days prior to step 1 registration based upon a CBC)

Absolute neutrophil count \>= 1500 cells/mm\^3 (within 60 days prior to step 1 registration based upon a CBC)

Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) \< 1.5 x the upper limit of normal (within 60 days prior to step 1 registration)

Total bilirubin (=\< 1.5 mg/dl) normal unless history of Gilbert's syndrome (within 60 days prior to step 1 registration)

The patient or a legally authorized representative must provide study-specific informed consent prior to step 1 registration

What this study is about