Prostate Cancer: What Your Psa And Gleason Score Mean

When you have been diagnosed with prostate cancer, the first line of defense will be knowing what the numbers you will hear actually mean.

If you have been told by your doctor that prostate cancer has been detected and confirmed, it is important to know what some of the numbers mean that you will be hearing. Knowing the facts is the first line of defense and will allow you to make reasonable choices regarding treatment options. Be sure to talk with your oncologist about all of these options and what is best for your particular case. The following facts should help to prepare you for that discussion.

One of the numbers you will be hearing is the "PSA." This means prostate specific antigen. This blood test specifies the amount of a certain protein in the blood that is made only by the prostate gland; hence the antigen (particle) that is measured is "prostate specific."

In general, although this is controversial, there is a rough correlation between the level of PSA in the blood and the amount of cancer that is present. This is used in several statistical models that attempt to predict the risk of spread of the cancer and thus help your doctor decide which treatment options might be best for you.For example, many doctors feel that prostate seed brachytherapy is only appropriate and is most curable for patients with a PSA of 10 or below.

A second factor which fits into the statistical models to predict risk of spread is the "Gleason score." The Gleason score describes the degree of aggressiveness the cancer displays when looked at under the microscope by a pathologist. There are two components to the Gleason score, one of them a "big picture" overall pattern, and the other a "forest for the trees" more specific pattern. For example, if you were a botanist, you might try to measure the overall overgrowth of a forest from a helicopter, as well as examining the forest's understructure from close range. The major pattern is the first number of the Gleason score, and the minor pattern is the second number, and the two are added together to make the Gleason score.

For example, a biopsy showing a major pattern of 3 and a minor pattern of 3 is labeled as "Gleason score 3 + 3 = 6 prostate cancer."Both the major and minor patterns range from 1 to 5, but a number better than 3 is very unusual for either one, so a Gleason 6 cancer is relatively well behaved compared to, for example, a cancer with a Gleason score of 4 + 4 = 8.

Gleason 3 + 4 = 7 cancers are considered intermediate in the amount of aggressiveness they normally display. This would mean they are intermediate in their tendency to spread distantly. Early spread implies a higher chance of having scattered through the bloodstream to distant sites before the cancer can be removed or killed with radiation therapy, and thus a lower chance of curability. Some cancers will have spread even though there is no way to prove that they have spread, thus we are left with statistical models to predict how curable a given patient is.



The final number used in the statistical models to predict the chance of a treatment cure is the "stage." This has three components as well: how the prostate feels on digital rectal examination (DRE), whether or not the cancer has spread to nearby lymph nodes by radiographic evaluation or by surgical sampling of the nodes, and the assessment of whether or not distant metastatic deposits are present in the bones by bone scan. A bone scan can be negative (normal) even when there is microscopic spread, too small to detect by bone scan, hence the reliance on the statistical models described above to predict risk of spread.

In general there are four stages for prostate cancer. The stages are I, II, III, and IV.Stage is a description of the extent of the cancer after a complete "staging" evaluation (such as blood tests or x-rays) at the time of initial diagnosis. This stage is a one-time label given to every prostate cancer to help predict prognosis.The patient does not "move from one stage to another," no matter what happens with the cancer.

Stage IV indicates verifiable spread to distant metastatic sites, such as in prostate cancer would normally be the bones if there is any spread.Stage III indicates a tumor that is large and aggressive feeling by DRE. Stage III cancers are becoming increasingly more rare in the era of PSA screening to detect prostate cancers.

Stage II cancers are the vast majority of prostate cancers detected these days and most of them carry a relatively favorable risk of cure, i.e. lack of even microscopic spread to remote sites prior to removal or irradiation of the cancer. Stage II cancers have no sign of spread to the nearby lymph nodes or to distant metastatic sites, such as the bones. Thanks to statistical models noted above, based on PSA and Gleason score, not all patients require a bone scan or CT scan to prove they are stage II and of favorable prognosis. In other words, if your Gleason score and PSA are both relatively low you may not need a bone scan or a CT scan to prove absence of regional or distant spread.

Stage I cancers are so rare and of good prognosis that some experts believe they may not even require treatment for cure.

The good news about prostate cancer is that with regular screening, in most cases it is very curable and can be treated successfully.

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