Obese men may have prostate cancer despite relatively low values on a prostate cancer screening test called the PSA test, researchers said in The Journal of the American Medical Association Wednesday.
The test may yield falsely reassuring results because obese people have more blood in their bodies due to their girth, thus diluting the concentration of the protein doctors use to detect the presence of prostate tumors.
The prostate gland produces a protein called prostate-specific antigen, or PSA. Only prostate cells produce it and if levels are higher it suggests the cells are growing -- which can be a sign of cancer although an enlarged prostate can also send PSA levels up.
The researchers examined medical records for nearly 14,000 men who had undergone surgery to treat prostate cancer between 1988 and 2006 at Johns Hopkins Hospital in Maryland, Duke University in North Carolina or five U.S. Veterans Affairs hospitals in California, Georgia and North Carolina.
Men with a body mass index, or BMI, indicating obesity had a higher blood volume and lower PSA concentrations. The most obese men had PSA concentrations 11 to 21 percent lower than those recorded in men of normal weight, according to their findings.
Dr. Carmen Rodriguez, an American Cancer Society epidemiologist who participated in the study, said the findings were particularly important considering the rising rates of obesity in the United States and worldwide.
Rodriguez said doctors had known obese men were at higher risk of developing more aggressive prostate cancer. She said this study indicates that some obese men could have had false negative results in PSA tests, with their cancer then detected much later after it had grown more advanced and more dangerous.
Worldwide, prostate cancer is estimated to kill about 221,000 people annually, with 679,000 new cases diagnosed.
The American Cancer Society estimates that about 27,000 men will die from prostate cancer in the United States this year and about 219,000 men will be diagnosed with it.
Source:Xinhua/Agencies
|
Comment
Tell A Friend
Print Format
Save Article