Prostate Cancer Diagnosis and Classification
When prostate cancer is suspected, a biopsy of the prostate gland, in which a sample of the prostate tissue is removed for microscopic evaluation, may be advised. Prostate cancer is characterized by both grade and stage. Grade is a term used to describe how closely a tumor resembles normal tissue. Grade can also determine how quickly the tumor is likely to grow and spread. The term Stage refers to the extent that the prostate cancer has spread from the original site to other parts of the gland or beyond to other parts of the body. Prostate cancer is classified using three criteria:
PSA is a blood test for a prostate-specific antigen. PSA is a substance produced by the prostate and may show higher levels in the blood of men who have prostate cancer, benign prostatic hyperplasia, or infection or inflammation of the prostate. It is recommended that men have annual screenings along with a rectal exam, so doctors can compare PSA levels over time to see if a pattern appears. An isolated PSA test that returns a low score is not enough of a true indicator to determine whether a man has prostate cancer.
PSA Score Classifications:
Low = 10 or under
Moderate = Greater than 10 and less than or equal to 20
High = Greater than 20
The Gleason score is a grading system for prostate cancer that looks at the tumor tissue under a microscope to determine how malignant the cells appear. A grade between 1 and 5 is given for both the major and minor components of the prostate cancer. The higher the number, the more aggressive the cancer appears under the microscope. The two most prominent components are added together to give an overall score, which ranges from 2-10. High-grade tumors in the 8-10 range are more aggressive and are more likely to spread than low-grade.
Gleason Score Classifications:
Low = 2 - 6
Moderate = 7
High = 8 - 10
The American Joint Committee on Cancer (AJCC) has developed a staging system, which classifies tumors by their anatomic location and the way tissues and cells are viewed under the microscope. Using TNM as a system for describing the extent the cancer has grown, T describes the size of the tumor and whether it has invaded nearby tissue, N describes any lymph nodes that are involved, and M describes metastasis (spread of cancer from one body part to another.)
The AJCC works in conjunction with other leading organizations including: The National Cancer Society, American College of Physicians, American College of Radiology, The National Cancer Institute and many other worthy institutions. The goal of AJCC is to formulate and publish systems of classification for cancer, which will be acceptable to and used by the medical profession to select the most effective treatments, determine prognosis, and evaluate cancer control measures. The mission of the AJCC is “to create and promote a taxonomy of cancer patient groups that accurately predicts outcomes by incorporating traditional (TNM) and newer data in a timely and dynamic process." Presently the TNM staging system is the universal language of cancer staging to date.
Upon request, your doctor can provide you with the TNM Definition determined for your prostate cancer.