Prostate cancer is the most common cancer in men after lung cancer. It often grows slowly and can go undetected for years. The prostate is a gland located behind the penis that produces seminal fluid. Risk factors for prostate cancer include age, race, family history, diet, and hormones. Tests for early detection include a PSA test, digital rectal exam, and transrectal ultrasound. Treatment depends on the stage of cancer and may involve surgery, radiation therapy, hormone therapy, or chemotherapy, with potential side effects like fatigue, urinary problems, and sexual issues.