PROSTATE CANCER SYMPTOMS
Prostate-specific antigen (PSA)
The prostate gland makes a protein called prostate-specific antigen, or PSA. A healthy man without prostate tumor should have a small amount of PSA circulating in his blood.
Some conditions related to the prostate can cause the gland to produce more PSA than normal. These include prostatitis, benign prostatic hyperplasia (enlarged prostate), and prostate tumor.
Prostate-Specific Antigen (PSA) Blood Test
Prostate-specific antigen (PSA) is a substance produced by the prostate gland. Elevated PSA levels may indicate prostate tumor, a non-tumorous condition such as prostatitis, or an enlarged prostate.
Most men have PSA levels under four (ng/mL) and this has traditionally been used as the cutoff for concern about the risk of prostate tumor. Men with prostate tumor often have PSA levels higher than four, although it is a possibility at any PSA level. According to published reports, men who have a prostate gland that feels normal on examination and a PSA less than four have a 15% chance of having prostate tumor. Those with a PSA between four and 10 have a 25% chance of having prostate tumor and if the PSA is higher than 10, the risk increases and can be as high as 67%.
The American tumor Society says men should talk to their physicians about the benefits, risks, and limitations of prostate tumor screening before deciding whether to be tested. The group’s guidelines make it clear that prostate-specific antigen (PSA) blood testing should not occur unless this discussion happens. They recommend that most men at average risk for prostate tumor start the discussion at age 50 and those with higher risk for prostate tumor should start the discussion earlier.
The American Urological Association recommends that men ages 55 to 69 who are considering screening should talk with their physicians about the risks and benefits of testing and proceed based on their personal values and preferences. The group also adds:
PSA screening in men under age 40 is not recommended.
Routine screening in men between ages 40 and 54 at average risk is not recommended.
To reduce the harms of screening, a routine screening interval of two years or more may be preferred over annual screening in those men who have decided on screening after a discussion with their physician. As compared to annual screening, it is expected that screening intervals of two years preserve the majority of the benefits and reduce over diagnosis and false positives.
Routine PSA screening is not recommended in men over age 70 or any man with less than a 10-15 year life expectancy.
Elevated PSA levels may indicate prostate tumor or a non-tumorous condition such as prostatitis or an enlarged prostate.
Your PSA level can also be affected by other factors:
Age. Your PSA will normally go up slowly as you age, even if you have no prostate problems.
Treatments. Some substances may affect blood PSA levels. Tell your health care provider if you are taking finasteride (Proscar or Propecia) or dutasteride (Avodart). These substances may falsely lower PSA levels typically by half of what it would normally be.
If your PSA level is high, your physician may recommend that you get a prostate biopsy to test for tumors.
Although the PSA test is used mainly to screen for prostate tumor, it is valuable in other situations:
To guide treatment. Along with a physicians exam and tumor stage, the PSA test can help determine how advanced a prostate tumor is. This may affect treatment options.
To determine treatment success. After an operation or radiation, the PSA level can be monitored to help determine if treatment was successful. PSA levels normally fall to very low levels if the treatment removed or destroyed all of the tumor cells. A rising PSA level can mean that prostate tumor cells are present and your tumor has come back.
Staging of prostate tumor is used to communicate how advanced the disease is and to help plan treatment. Stages range from 1 to 4, with the disease being most advanced in stage 4. There are a number of factors that go into this labeling.
Prostate tumor, like many other tumors, is described based on the American Joint Committee staging system. This staging system is based on the size or extent of the tumor, the number of lymph nodes involved, and whether or not the tumor has spread or metastasized to distant sites or organs. Prognostic groups are further determined based on two additional factors: the PSA level and the Gleason score.
The role of PSA in staging
PSA levels are just one factor used in determining the stage and prognostic groups of prostate tumor.
Some men who have prostate tumor do not exhibit elevated PSA levels, and some non-tumorous conditions, like a prostate infection or benign enlargement, can cause high PSA levels.
Stage 1 prostate tumor is characterized by a Gleason score of less than 6: the tumor is restricted to one half of the prostate with no spreading to surrounding tissues and a PSA level below 10. The Gleason score compares tumor cells to normal cells. The more the cells differ from normal cells, the higher the score and the more aggressive the tumor. Like the PSA level, it is just one piece of the puzzle.
In stage 2A prostate, the tumor is still restricted to one side of the prostate, but the Gleason score may be up to 7, and the PSA levels are greater than 10 but less than 20 ng/mL.
By stage 2B, the tumor may have spread to the opposite side of the prostate gland, but it also may still be contained on one side. If the tumor is still restricted to one half of the prostate, a Gleason score of 8 or higher or a PSA level of 20 or greater categorizes the tumor as stage IIB. If the tumor has spread to both sides of the prostate then the stage is IIB regardless of the Gleason score and the PSA level.
Stages 3 and 4
By the time prostate tumor has reached stage 3 or stage 4, the tumor is very advanced. At this point, the stage is determined by the extent of the spread of the tumor, and the PSA level and Gleason score do not factor in the staging. In stage III the tumor has grown through the prostate capsule and may have invaded nearby tissue. By stage 4 the tumor is fixed or immovable and invades nearby structures beyond the seminal vesicles. It may also have spread to distant sites like lymph nodes or bones.
To determine the size and extent of the prostate tumor, physicians use imaging techniques like CT scans, MRIs, PET scans, and biopsies of prostate and other tissue.