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Did PSA Test's Decline Spur Rise in Prostate Cancers?
Researchers report 3 percent annual rise in intermediate- and high-risk cases
By Dennis Thompson
TUESDAY, Feb. 24, 2015 (HealthDay News) -- U.S. recommendations against the PSA test for prostate cancer might have prompted a small but measurable increase in the number of higher-risk cases diagnosed recently, according to a new study.
The U.S. Preventive Services Task Force (USPSTF) in 2009 recommended that the PSA test not be used to screen men 75 years or older for prostate cancer, and in 2012 recommended that the PSA not be used for prostate cancer screening at all for any age group.
Between 2011 and 2013, the study authors noted a 3 percent per year increase in the percentage of prostate cancer patients who had a PSA level of 10 or higher at the time of their diagnosis. PSA levels of 10 or more signify intermediate or high-risk prostate cancer.
This trend suggests that an additional 14,000 men were diagnosed with higher-risk prostate cancer in 2014, and that an estimated 1,400 would have died from the disease that year, said study co-author Timothy Schultheiss, director of radiation physics at City of Hope Medical Center in Duarte, Calif.
"We believe our data indicate that the USPSTF might reconsider their recommendation," Schultheiss said. "We need to be intelligent about who we screen and who we treat. We're not suggesting that everyone be screened using PSA, but we're not suggesting that no one be screened using PSA."
The USPSTF's position of recommending against all PSA screening is "extreme," Schultheiss concluded.
In response, USPSTF Chairman Dr. Michael LeFevre said the study authors' conclusions regarding the PSA test were premature and based on incomplete data. For example, "this study doesn't appear to include data on the frequency of diagnosis of low, intermediate or high-risk prostate cancers in the U.S. population," he said.
Schultheiss said he and his colleagues did examine the severity of prostate cancer in the men studied, and those indicators "did not change appreciably during the same period of time."
Based on that statement and the findings presented, LeFevre said, "It is unclear, from the data made available to us at this time, how this study could be used to draw conclusions about the impact of the USPSTF's 2012 recommendation on PSA screening for prostate cancer on the number of high-risk cancers being diagnosed either before or after the recommendation."
Findings from the study are to be presented Thursday at an American Society of Clinical Oncology meeting in Orlando, Fla. Findings presented at meetings are generally considered preliminary until they've been published in a peer-reviewed journal.
The PSA test looks at bloodstream levels of prostate-specific antigen, a protein produced by the prostate gland. PSA levels are often elevated in men with prostate cancer, according to the U.S. National Cancer Institute (NCI). However, a number of studies have called into question the effectiveness of PSA screening, according to the NCI.
One reason? Men with prostate cancer usually do not die from their cancer. "Most prostate cancers found by PSA screening are slow growing, not life threatening, and will not cause a man any harm during his lifetime," LeFevre said.
On the other hand, surgery or radiation therapy to treat prostate cancer can lead to a number of side effects, such as impotence and incontinence. This raises the question of whether treatment is worthwhile given that it can significantly harm a man's quality of life to cure a cancer that likely isn't life-threatening.
The task force came out against PSA screening because evidence shows the test provides "a very small potential benefit and significant potential harms," LeFevre said.
The new study relied on data from roughly 87,500 men treated for prostate cancer between January 2005 and June 2013.
In addition to finding an increase of 3 percent a year for men diagnosed with prostate cancer with a PSA of 10 or higher, the researchers discovered nearly double the increase -- about 6 percent per year -- for men 75 or older, Schultheiss said.
Prior to 2011, there had been a steady decline in the percentage of men with prostate cancer with a PSA of 10 or higher, the researchers said.
"If you don't screen the people, then when they show up with prostate cancer, the horse is out of the barn," Schultheiss said. "By missing early disease, then you're going to catch it when it's later, when it's palpable or causing symptoms. And that, of course, makes it much more difficult to treat."
Dr. Charles Ryan, a medical oncologist at the University of California, San Francisco and an ASCO expert, noted that the 2014 estimates regarding high-risk cases and deaths were just predictions and not supported by the data at hand, which only extended into 2013.
"It will certainly take longer for such predictions to develop, if they do develop at all," Ryan said. However, he added, "This is a study that really does add some new insight into the ongoing debate over the risks and benefits of prostate cancer screening."
For more information on PSA testing, visit the National Cancer Institute.
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