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Introduction to Prostate Cancer
Staging of Prostate Cancer
Staging is the method used by doctors to evaluate how far the cancer has spread once it has been discovered. Staging plays an important role in determining both the treatment options as well as predicting the prognosis (chances of recovery). In general, there are 4 clinical stages of prostate cancer:
Stage I: The cancer is small, is confined to the prostate gland, and cannot be felt during a digital rectal exam (DRE). It is found by chance when surgery is done for another reason, usually for benign prostatic hyperplasia (BPH). Many men with Stage I prostate cancer have no signs or symptoms of the disease.
Stage II: The cancer is more advanced than in Stage I but it has still not spread outside the prostate. Stage II cancer may be discovered by a DRE, transrectal ultrasound, or by an elevated PSA level. Stage II prostate cancer is more likely to spread beyond the prostate as compared to Stage I disease and is also more likely to cause symptoms.
- Sixty-five to 98% of men with stage 1 and 2 prostate cancer will live for more than five years after they are diagnosed. Some of these patients will be cured with treatment. Others may have a cancer that is so slow growing that it will not have progressed much in this time, even with no treatment at all.
Stage III: The cancer has spread outside the prostate (e.g, seminal vesicles) but it has not spread to the regional lymph nodes or to distant organs.
Stage IV: The cancer may be in nearby muscles and organs (bladder; rectum). It may have spread to the lymph nodes or may have spread to distant parts of the body (e.g., bones).
- Approximately 20-30% of men have Stage IV prostate cancer at the time of diagnosis (meaning the cancer has spread to another part of their body). About 1 in 3 (30%) men with advanced prostate cancer will live for more than five years after diagnosis. On average, men with Stage IV prostate cancer can expect their cancer to respond to treatment for about 12 to 18 months. Average survival after that time is approximately two years.
Recurrent prostate cancer is cancer that has come back (recurred) after a time when it could not be detected. It may recur in or near the prostate. Or it may recur in any other part of the body, such as the bones.
One staging system for prostate cancer is known as the TNM (tumor, node, metastasis) system.
T = Tumor - The "T" designation refers to the extent of invasion of the tumor into the prostate and nearby tissue and other organs. The extent of tumor invasion is scored on a numerical scale ranging from 1 to 4. In general, the higher the "T" score, the greater the extent of invasion of the tumor into the deeper layers of tissue.
N = Lymph Node Involvement - The second aspect of the TNM staging system measures whether or not the cancer has spread to the regional (nearby) lymph nodes and, if so, the size of the lymph nodes. The extent and size of lymph node involvement is scored on a numerical scale ranging from 0 to 3. In general, the higher the "N" score, the greater the extent of lymph node involvement. In prostate cancer, the regional lymph nodes are the nodes of the true pelvis, which are the nodes below the bifurcation of the common iliac arteries. Distant lymph nodes are outside the true pelvis and their involvement constitutes distant metastasis.
