Supporters say watchful waiting is a practical alternative for men in their late 60s or older, whose lifespans may be limited by advanced age and serious ailments such as heart disease. If treated, these men could suffer the trauma and adverse effects of cancer therapy with little or no benefit. Not all prostate cancer is equal. One type of tumor may lie dormant for years while another is virulent and deadly. Deciding whether to wait or act can be difficult because physicians often can't judge conclusively which tumors might spread.
Size can give some indication.
Another gauge, the Gleason system, identifies a tumor's growth potential based on its appearance under the microscope. The system distinguishes progressive grades of prostate cancer on a scale of 2 to 10. Cells distributed randomly with uneven edges are more apt to spread and receive a high Gleason number. This ranges from stage A, where the tumor is still microscopic and confined, to stage D, where cancer has spread to the lymph nodes or to other organs outside the prostate. The lower the staging, the more likely the cancer can be cured.