Even when symptoms respond to antibiotic therapy, you still can’t rule out prostate cancer completely because both conditions, an infection and cancer, can exist at the same time. Prostate cancer can be confirmed or ruled out using several investigative methods: a rectal examination, ultrasound, CT-scan, laboratory analyses (acid phosphatasis, prostate specific antigen), and biopsy. You can consult an urologist for an expert opinion, diagnosis, and treatment.