Prostate cancer treatment is trending toward risk-specific therapies
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 published in JAMA (2015; doi:10.1001/jama.2015.6036).
In the first study to document updated treatment trends, researchers found that from 2010 to 2013, 40% 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, in the years from 1990 through 2009, less than 10% overall of patients with low-risk prostate cancer pursued active surveillance. Rates for radiation therapy in this low-risk group have also slipped since 1995, the authors noted in the study.
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% were treated with this therapy in 1990 to 1994 versus 3.8% in 2010 to 2013. Among those with high-risk disease, 30% and 24% 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 University of California San Francisco (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 patients with prostate cancer from 45 urology practices nationwide, collected in UCSF's CaPSURE registry. In patients age 75 years and older, they observed that the rate of active surveillance had soared from 22% in the 2000-to-2004 period, up to 76% in the 2010-to-2013 timeframe. However, the incidence of surgery had stagnated in this high-risk group.
Patients with low-risk disease 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 hope the results of their 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.