A Study of Adding Apalutamide to Radiotherapy and LHRH Agonist in High-Risk Patients With Hormone-Sensitive Prostate Cancer

Inclusion Criteria: * Histologically confirmed adenocarcinoma of the prostate * Previously treated with radical prostatectomy with or without lymph node dissection and either: a) for biochemical recurrence after radical prostatectomy (RP): any post-operative prostate-specific antigen (PSA) measurement of less than (\<) 0.1 nanogram/milliliter (ng/mL) within 12 months after RP and without any PSA greater than and equal to (\>=) 0.1 ng/mL within the 4 to 8-week period after RP or b) for persistent PSA after RP: PSA \>=0.1 ng/mL within the 4 to 8-week period after RP, confirmed by additional measurement at least 3 weeks later * Be able to swallow whole the study drug tablets or follow the instructions for admixing with apple sauce * Results of the Prostate specific membrane antigen-positron emission tomography (PSMA-PET) at screening as determined by blinded independent, central review (BICR), must be: PSMA-PET-negative for any prostate cancer lesions (that is, no loco-regional lesion and no distant lesions); or PSMA-PET-positive for at least one loco-regional (pelvic) lesion without distant extra-pelvic lesion; or PSMA PET- positive for at least one loco--regional (pelvic) lesion with extra-pelvic lesion(s). * High risk of developing metastasis defined as; a) for biochemical recurrence after RP: pathological Gleason score greater than or equal to (\>=) 8 evaluated from prostate tissue specimen at radical prostatectomy, or prostate-specific antigen doubling time (PSADT) less th…