An Efficacy and Safety Study of JNJ-56021927 (Apalutamide) in High-risk Prostate Cancer Subjects Receiving Primary Radiation Therapy: ATLAS

Inclusion Criteria: * Age \>= 18 years * Indicated and planned to receive primary radiation therapy for prostate cancer * Histologically confirmed adenocarcinoma of an intact prostate, and 1 of the following at diagnosis: 1) Gleason score \>=8 and \>=cT2c, 2) Gleason score 7, PSA \>=20 nanogram per milliliters (ng/mL), and \>=cT2c * Charlson index (CCI) \<=3 * An Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) grade of 0 or 1 * Adequate organ function: (1) aspartate aminotransferase (AST), alanine aminotransferase (ALT), within normal limits (WNL), (2) serum creatinine less than (\<) 1.5 milligram/deciliter (mg/dL) (\<133 micromoles/Liter \[mcmol/L\]), (3) platelets greater than or equal to (\>=)140,000/microLiter (mcL), independent of transfusion and/or growth factors within 3 months prior to randomization, (4) Hemoglobin \>= 12.0 gram/deciliter (g/dL) (7.4 millimloes \[mmol\], independent of transfusion and/or growth factors within 3 months prior to randomization * Participants who are sexually active (even men with vasectomies) and willing to use a condom and agree not to donate sperm during the trial * Signed, written, informed consent * Be able to swallow whole study drug tablets Exclusion Criteria: - * Presence of distant metastasis, (clinical stage M1). Isolated pelvic nodal disease below the iliac bifurcation (clinical stage N1) is not an exclusion. Diagnosis of distant metastasis (clinical M stage; M0 versus M1a, M1b, M1c) and pelvic nodal diseas…