After decades of overtreatment for low-risk prostate cancer and inadequate management of its more aggressive forms, patients are now more likely to receive medical care matched to level of risk, according to a study by researchers at UC San Francisco.
In the first study to document updated treatment trends, researchers found that from 2010 to 2013, 40 percent of men with low-risk prostate cancer opted for active surveillance, in which the disease is monitored closely with blood tests, imaging studies and biopsies. Treatment is deferred unless these tests show evidence of progression.
In contrast, less than 10 percent overall of low-risk prostate cancer patients pursued active surveillance in the years from 1990 through 2009. Rates for radiation therapy for this low-risk group have also slipped since 1995, the authors noted in the study published in JAMA earlier this month.
Meanwhile men with higher-risk tumors are more likely to undergo surgical removal of the prostate and/or radiation, localized treatments that are more effective than androgen-deprivation therapy alone, in which drugs are taken to block the hormones that stimulate the growth of prostate cancer cells. In men with intermediate-risk disease, 9.7 percent were treated with this therapy in 1990 to 1994, versus 3.8 percent in the period of 2010 to 2013. Among those with high-risk disease, 30 percent and 24 percent of patients respectively underwent this treatment in these same periods.
"We expected to see a rise in surveillance rates, but were surprised by the steepness of the trajectory. It shows a major shift toward appropriate, risk-adapted management of the disease," said corresponding author Matthew Cooperberg, MD, MPH, associate professor in the departments of Urology and Epidemiology & Biostatistics at UCSF, and Helen Diller Family chair in Urology at the UCSF Helen Diller Family Comprehensive Cancer Center.
"Active surveillance has been a mainstay for years at UCSF and a few other academic centers, but is increasingly broadly endorsed in recent years. Our study follows on from numerous others that have documented consistent overtreatment of low-risk cancer that would never cause any symptoms or loss of life expectancy had it never been diagnosed. At the same time we're seeing more aggressive management of higher-risk disease, which will lead to better outcomes," he said.
Cooperberg, and senior author Peter Carroll, MD, MPH, analyzed data of close to 10,500 prostate cancer patients from 45 urology practices nationwide, collected in UCSF's CaPSURE registry. In patients aged 75 or older, they observed that the rate of active surveillance had soared from 22 percent in the 2000-to- 2004 period, up to 76 percent in the 2010-to-2013 timeframe. However, the incidence of surgery had stagnated in this high-risk group.
Low-risk patients seeking treatment may be younger and motivated by anxiety, perhaps related to a family history of cancer, or obstructive urinary symptoms, said Carroll, professor and chair of the Department of Urology at UCSF.
The authors say that they hope the results of the study will generate renewed discussion on the merits of PSA screening, a blood test that measures a protein produced by the prostate gland. PSA levels are frequently elevated in men with prostate cancer, but testing has invited controversy, because it has led to unnecessary treatment in men with low-risk disease.
"Because of concerns about overtreatment, many primary care physicians no longer support PSA testing. This means that low-risk tumors, which do not require treatment, go unnoticed," said Carroll. "But it also means that high-risk tumors that are potentially lethal without early identification and intervention may go unnoticed, too. We hope the results of this study will lead toward a smarter screening and treatment paradigm, which is what many men need and deserve."
CaPSURE was supported by funding from TAP Pharmaceutical Products until 2007. It is currently funded by the U.S. Department of Defense and the UCSF Department of Urology.
Cooperberg has received consulting fees from Myriad Genetics, Astellas and Bayer. Carroll is receiving grants and has received personal fees from Genomic Health. The UCSF Department of Urology is receiving grants from Myriad Genetics, Genomic Health and GenomeDx.
No sponsor or funding organization played a role in the design and implementation of the study, or the publication of the manuscript. No further disclosures were reported.
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