After prostate cancer is diagnosed, doctors will do staging tests involving CT/MRI scans and bone scans to see is cancer has spread beyond the prostate. Staging refers to determining the extent of disease.
The cancer is still localised in the prostate in stage I and II. Prostate cancer has spread beyond the prostate in stage III and IV.
Singapore Cancer Registry statistics for 2009-2013 showed that 61.6% of men were diagnosed with prostate cancer that had not spread beyond their prostate (Stage I and II). On the other hand, 10.6% and 27.8% of men were diagnosed at stages III and IV respectively.
The key to early diagnosis of prostate cancer before it spreads beyond the prostate is to discuss with your doctor about doing prostate cancer screening from age 50 onwards (or earlier if you have a family history of prostate cancer). Early prostate cancer most often do not cause any symptoms, so you cannot rely on symptoms to warn you of cancer.