How is prostate cancer diagnosed?  

History/Exam/Tests. Prostate cancer (cap) does not generally have symptoms until it is fairly advanced and untreatable. Thus screening for cap has been done by asking for any family history of cap, examining the prostate through a rectal exam and by checking a test called prosate specific antigen(psa). If the exam or psa are abnormal, an ultrasound-guided biopsy through the rectum acquires tissue to assess for cap.
Prostate biopsy. A prostate biopsy ( typically ultrasound guided ) is the way it is diagnosed.
Biopsy. Once a consideratoin is made for a diagnosis of prostate cancer, the next step is a prostate biopsy. This is an office procedure. This includes placement of a rectal ultrasound probe to visualize the prostate. A number of biopsies are taken and then examined under the microscope to determine if malignant cells are present.