There are several staging systems to categorize the levels of prostate cancer. The most widely accepted system is the TNM classification.
Stage I - (T1) - Tumor remains confined to the prostate and is too small to be detected on DRE. This is an incidentally found cancer either by an elevated PSA or found after a transurethral resection of the prostate.
Stage II - (T2) - Tumor is still confined to the prostate, but is now large enough to be felt on DRE.
Stage III - (T3) - The prostate cancer has spread through the prostatic capsule and may involve locally surrounding tissues such as the seminal vesicles.
Stage IV - (T4) - Metastatic prostate cancer in which the cancer involves lymph nodes or bony sites or other organs such as the liver or lungs.
Prostate cancer tends to be a slowly progressive cancer. Absolute prediction of when a localized cancer will spread and cause significant problems is not well understood. Some information has been provided by a study published in JAMA (The Journal of the American Medical Association). In this study of patients diagnosed with prostate cancer in Conneticut who did not have initial treatment, the histologic analysis (Gleason's sum score) was the most accurate apparent predictor of the speed of prostate cancer progression. Men with low grade prostate cancers (Gleason sum score 2 to 4) had such a low rate of progression that survival over 15 years was very similar to that of age-matched men who did not have cancer. However, men with Gleason 8-10 cancers had only a 50% survival rate at 5 years. Intermediate progression and death rates occurred for men with Gleason 5-7 sum scores.
Progression after biochemical (PSA-detected) recurrence following attempted local treatment can also be predicted based on the time of PSA detection after treatment and the rate of PSA change. Recent information has suggested that men with prostate cancer who recur with a PSA level above 0.3 ng/ml after radical prostatectomy are likely to do very well for a long period of time if the recurrence is first detected after 2 years and the PSA doubling time (the time necessary for PSA level to increase by a factor of 2) is greater than 10 months. Men with these characteristics will typically not develop any evidence of prostate cancer spread to bone for at least 8 years after detection of the PSA increase (Pound et al., JAMA.)