• Pathologically (histologically or cytologically) proven diagnosis of adenocarcinoma of prostate cancer

• High-risk disease defined as having at least one or more of the following:

‣ cT3a-T3b by digital exam or imaging (American Joint Committee on Cancer \[AJCC\] 8th edition \[Ed.\]) Note: cT4 by imaging or on digital rectal exam is not allowed

⁃ The patient's prostate specific antigen (PSA) value \> 20 ng/mL prior to starting androgen deprivation therapy (ADT) Note: Patients taking a 5-alpha reductase inhibitor (ex finasteride or dutasteride) are eligible The baseline PSA value should be doubled for PSAs taken while on 5-alpha reductase inhibitors

⁃ Gleason Score of 8-10

⁃ Pelvic node positive by conventional imaging with a short axis of at least 1.0 cm

• Prostate gland volume less than 100 cc prior to initiation of ADT as reported at time of biopsy or by separate measure with ultrasound or other imaging modalities including MRI or CT scan

• No definitive clinical or radiologic evidence of metastatic disease outside of the pelvic nodes (M1a, M1b or M1c) on conventional imaging (i.e. bone scan, CT scan, MRI); Negative prostate-specific membrane antigen (PSMA) positron emission tomography (PET) is an acceptable substitute

• Age \>= 18

• Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-2

• No prior radiotherapy to the region of the study cancer that would result in overlap of radiation therapy fields

• No prior radical prostatectomy

• No prior ablative or focal therapy to the prostate (including, but not limited to, transrectal or transurethral high-intensity focused ultrasound \[HIFU\], laser ablation, cryotherapy, irreversible electroporation \[IRE\], and vascular-targeted photodynamic therapy)

• Prior pharmacologic androgen ablation for prostate cancer is allowed only if the onset of androgen ablation (both luteinizing hormone releasing hormone \[LHRH\] agonist and oral anti-androgen) is =\< 185 days prior to registration; Please note: PSA prior to the start of any ADT will be used to define disease

• No contraindication to prostate MRI (required for planning of radiotherapy in both arms)

• Patients enrolled in NRG-GU009 must be enrolled in NRG-GU013 prior to radiation therapy treatment planning and start of radiation therapy