Treatment of any cancer is based on the stage of the cancer when it is diagnosed. Staging is performed for two purposes – to guide initial treatment decisions and to predict the patient’s survival outcome after therapy. Based on the TNM (tumor, node, metastases) staging system, prostate cancer is divided into four major stages based on the tumour size, lymph node involvement, and degree of metastasis or spread beyond the prostate. Two other markers are also taken into consideration: the prostate-specific antigen (PSA) level and the Gleason score, a scale for determining how aggressive a prostate cancer is. Other factors such as patient age, general health and life expectancy also influence decisions about the treatment regimen that is chosen.
Some of the different treatment options for the various cancer stages are described below:
Stage I describes a cancer that is confined within the prostate gland and has not spread to the nearby lymph nodes. In addition, the Gleason score must be 6 or less and the PSA level less than 10 ng/mL.
These cancers can be slow growing, remaining confined to the prostate and not causing any symptoms and often an approach called watchful waiting is recommended. This involves monitoring the patient’s PSA levels and performing regular ultrasound scans to check for growth of the cancer. If the patient does opt for treatment, radiotherapy (external beam or brachytherapy) may be initiated or a radical prostatectomy may be performed.
A stage IIa tumor is still confined within the prostate gland but is only present in one side of the gland and has not spread to nearby lymph nodes or elsewhere. The Gleason score may be as high as 7 and the PSA level as high as 19 ng/mL.
Stage IIb may refer to a cancer that is still confined to the prostate but is present in both sides of the gland and accompanied by any Gleason score and any PSA level. It may also refer to a cancer that is still confined to only one side of the prostate but where the PSA is 20 or more or the Gleason score is 8 or more.
Stage II cancers that are left untreated are more likely to spread than stage I cancers. However, in men without symptoms who are elderly or suffering from comorbidity, watchful waiting and monitoring of PSA levels is often a suitable option. In younger men that are otherwise healthy, treatment with surgery and radiotherapy are appropriate treatment options.
At this stage, cancer has spread beyond the prostate and may have reached the seminal vesicles but still does not involve nearby lymph nodes and has not spread to other parts of the body. Gleason score and PSA levels may be of any value.
Surgery and radiotherapy are still treatment options but the cancer carries a greater risk of recurrence after initial remission. Treatment options include radiotherapy along with hormone therapy, hormone therapy alone, radical prostatectomy followed by radiation therapy and for elderly men with no symptoms or with other serious health problems, watchful waiting may be advised. At this stage, prostatectomy is no longer nerve-sparing and also usually involves removal of the lymph nodes.
A stage IV cancer has either spread beyond the prostate to nearby structures other than the seminal vesicles, or to the lymph nodes, to distant sites in the body or to a combination of all three. This stage of cancer is not considered curable but can be effectively treated to relieve symptoms and prolong survival. Treatment usually begins with hormone therapy or radiotherapy and parts of the prostate tissue may be removed in a TURP (transurethral resection of prostate) procedure to ease symptoms.
Reviewed by Sally Robertson, BSc