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"Normal" PSA can be misleading
The prostate specific antigen, or PSA test, initially used to assess the response of prostate cancer patients to treatment, has been widely used as a screening test for the disease. A study published in the May 27 2004 issue of the New England Journal of Medicine has found that individuals with PSA values of 4.0 nanograms per milliliter or lower, considered to be within the normal range, are not necessarily in the safe zone when it comes to prostate cancer.
The researchers analyzed data obtained in the Prostate Cancer Prevention Trial, a double-blind placebo-controlled study that sought to determine whether the drug finasteride could help reduce the incidence of prostate cancer among 18,882 participants during a seven year period. The current study examined 2,950 men from the placebo group whose PSA levels were never higher than 4.0 nanograms per milliliter, whose digital rectal examinations were normal, and who underwent a biopsy of the prostate during the study period.
The biopsy results showed that 15.2 percent of the men with so-called normal PSA levels had prostate cancer. Of these, 14.9 percent had a Gleason score of at least 7, indicating an aggressive cancer. The risk of prostate cancer increased with PSA value, with those whose PSA was 0.5 ng per milliliter or less having the lowest incidence of the disease, and those whose PSA was between 3.1 and 4.0 nanograms per milliliter experiencing the greatest risk. High-grade prostate cancer, defined by a Gleason score of 7 or higher, was positively associated with increasing PSA scores. The majority of cancers identified in the study had a Gleason score of 6, which is associated with increased risk of progression if not treated.
The authors concluded, “There is no PSA value below which a man can be assured that he has no risk of prostate cancer.” Lowering the PSA threshold for proceeding to prostate biopsy could lead to overtreating some prostate cancers that may not be clinically important. Identifying biomarkers in serum and cancerous tissue may help differentiate important prostate tumors from those considered clinically unimportant.
Prostate Cancer Overview
Besides laboratory testing, physical examination, and investigative procedures to rule out the presence of prostate cancer (PC) and other diseases, an action plan to prevent their development should be considered. These types of preventive measures are preemptive, or defensive, measures. The most apparent of these relates to what we eat and drink.
Of all nutritional literature currently in existence relating to PC, the relationship between lycopene ingestion and the health of the prostate is the clearest. Lycopene consumption been found to decrease not only the risk of PC in multiple studies,but also the risk of breast, pancreatic and stomach cancer, as well as lung cancer.
Lycopene functions as a very potent antioxidant. In this regard, lycopene can trap singlet oxygen and reduce mutagenesis (gene mutations) in the Ames test. Other mechanisms of lycopene action may be operative as well. Lycopene at physiological concentrations can inhibit human cancer cell growth by interfering with growth factor receptor signaling and cell-cycle progression--specifically in PC cells--without evidence of toxic effects or apoptosis of cells. Studies of human and animal cells have identified connexin 43, a gene, whose expression is upregulated by lycopene and which allows direct intercellular gap junctional communication (GJC). GJC is deficient in many human tumors and its restoration or upregulation is associated with decreased proliferation.
Measures to prevent PC must be a routine part of the counsel that general practitioners and internists give their patients. Selenium intake of at least 200 micrograms a day should be a consideration in the prevention of PC throughout the world. Low plasma selenium is associated with a four- to fivefold increased risk of PC. In addition, levels of plasma selenium also decrease with age, resulting in middle-aged to older men being at a higher risk for low selenium levels. Ideally, baseline levels of selenium should be obtained before beginning routine selenium supplementation. It would make sense to begin such a micronutrient and mineral assessment at age 25 and perhaps every 10 years thereafter.
Lycopene is a carotenoid and the source of the red coloring of tomatoes, red peppers, red grapefruit, and watermelon. It may have the highest antioxidant properties of all the carotenoids. The powerful antioxidant action of lycopene helps to prevent the oxidation of serum lipids, thus promoting arterial health. Lycopene may also assist in maintaining cell-to-cell communication and modulating cytochrome p450 detoxification, factors that benefit susceptible tissue. Research has found that lycopene is better absorbed when preheated in, or co-ingested with fat.
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