Scientists at Wake Forest University School of Medicine and the University of Wisconsin-Madison have found that some elevated prostate-specific antigen (PSA) levels in men could possibly be caused by a hormone usually occurring in the body. Also, it may not necessarily be a predictor of the need for a prostate biopsy.
Parathyroid hormone is known to have been made by cells of the parathyroid glands, four small glands embedded in the thyroid. Though parathyroid hormone mainly controls calcium levels in the blood, recent study has shown that parathyroid hormone may be able to promote prostate cancer cell growth. This study by Schwartz and Skinner is the foremost one to suggest that parathyroid hormone also seems to promote prostate cell growth in men without prostate cancer.
High levels of PSA have traditionally been seen as a probable sign of prostate cancer in turn leading to the widespread use of PSA testing. However, they found that parathyroid hormone may perhaps increase prostate-specific antigen (PSA) levels in healthy men who do not have prostate cancer. Parathyroid hormone is known to be a substance the body produces to regulate calcium in the blood. These ‘non-cancer’ elevations in PSA may cause many men to be biopsied unnecessarily, which often results in unnecessary treatment.
Lead author of the study, Gary G. Schwartz, Ph.D., M.P.H., an associate professor of cancer biology and epidemiology and prevention at the School of Medicine said that, “PSA picks up any prostate activity, not just cancer. Inflammation and other factors can elevate PSA levels. If the levels are elevated, the man is usually sent for a biopsy. The problem is that, as men age, they often develop microscopic cancers in the prostate that are clinically insignificant. If it weren’t for the biopsy, these clinically insignificant cancers, which would never develop into fatal prostate cancer, would never be seen.”
Schwartz further said that since PSA screening is known to have become so widespread and more men are being biopsied. When the majority of men are told about them suffering from prostate cancer, they seem to return treatment even though it may not be needed. In reality, in only one of six cases does a biopsy diagnosis of prostate cancer result in a cancer that could be fatal if untreated.
Thus, high rates of prostate biopsy may lead to the over treatment of prostate cancer leading to an increased rate of the side effects of treatment including impotence and urinary incontinence.
For the purpose of the study, the authors were believed to have analyzed data from 1,273 men who participated in the National Health and Nutrition Examination Survey 2005-2006. More so, they were observed to have not reported any existing infection or inflammation of the prostate gland, prostate biopsy in the past month, or history of prostate cancer at the time of the survey.
After adjusting for age, race and obesity because PSA levels are known to increase with age, are higher in black men, and are lower in overweight men. The authors discovered if the level of parathyroid hormone in the blood appears to be high then the PSA level would be high as well.
In men whose parathyroid level was at the high end of normal, the PSA level seems to have increased by 43 percent thereby putting many in the range for the urologist to recommend a biopsy.
Skinner claimed that the finding appears to be particularly significant for black men. Moreover, about 20 percent of black men were noted to have elevated parathyroid hormone levels in contrast to about 10 percent of white men. Apparently, this signifies that blacks have a greater chance of being recommended for biopsy and over treated.
This finding could perhaps assist scientists in treating the prostate cancer screening test in order to better distinguish between those men who need to be biopsied and those who might be spared the procedure. Its possible that there are a lot of men out there with elevated PSAs that may be due to elevated parathyroid hormone rather than prostate cancer.
The findings of the study have been published in the journal, Cancer Epidemiology, Biomarkers and Prevention.