External Beam Radiation Therapy (EBRT) is a standard, first-line treatment for unfavorable intermediate-risk prostate cancer, often combined with 4–6 months of androgen deprivation therapy (ADT) to improve cancer control. It involves targeting the prostate with high-energy beams over a series of daily sessions, typically lasting 6–8 weeks.

EBRT is especially appropriate for patients who are not candidates for surgery or who prefer a non-invasive curative option. It provides excellent long-term outcomes but can cause side effects such as urinary urgency or frequency, rectal irritation, and gradual decline in erectile function. The addition of ADT enhances effectiveness by lowering testosterone, which helps reduce tumor activity and the risk of recurrence.