Prostate cancer is a form of cancer that develops in the prostate gland of the male reproductive system. Most prostate cancers grow slowly and occur in the form of malignant tumour that usually begins in the outer part of the prostate. In most men, the cancer grows very slowly. In fact, many men with the disease will never know they are suffering from prostate cancer. Early prostate cancer is confined to the prostate gland itself, and the majority of patients with this type of cancer can live for years without showing any signs and symptoms of cancer.