Men who have slow growing, low-risk prostate cancer may not live long enough to die of their illness. And since there’s no conclusive evidence that treating low risk prostate cancer extends survival, doctors might recommend monitoring the cancer and treating it only when it begins to spread.
That’s called active surveillance. It’s generally reserved for men with small, slow-growing tumors and a normal life expectancy of less than 10 to 15 years after diagnosis. Older men in particular are far more likely to die of heart disease and other causes than low-risk prostate cancer. That’s fueled mounting concerns that low-risk cases are being overtreated, with too many men experiencing side effects without benefits.
Doctors monitor men on active surveillance in three ways:
- periodically measuring the amounts of prostate-specific antigen in blood
- checking for tumor growth with digital rectal exams
- giving repeat biopsies at varying intervals.
Active surveillance takes off
Though it has a long history, active surveillance has only recently broadened its reach from academic cancer centers into the wider community. Now a new study shows its adoption is accelerating. “The trend is real and it’s a step in the right direction,” said Matthew Cooperberg, an associate professor of urology, biostatistics, and epidemiology at the University of California, San Francisco Medical Center, and the study’s lead author.
Cooperberg and his co-author Peter Carroll, chair of the UCSF urology department, reviewed data from more than 10,000 men with low-risk prostate cancer treated at 45 urology practices throughout the United States. From 1990 to 2009, the rate of using active surveillance among men who were an average of 66 years old when diagnosed hovered at just under 15%. But between 2010 and 2013, the rates spiked suddenly, to more than 40%. A similar trend was observed for men 75 years or older at diagnosis — active surveillance rates increased from 54% to 76% over the same time period.
“Over-treatment of low-risk prostate cancer is a significant problem, and these results suggest that it’s abating,” Cooperberg said.
With studies from Sweden, Australia, Michigan, and elsewhere showing similar increases, active surveillance “appears to be gaining traction as a standard management practice,” said Stacy Loeb, a urologist and researcher at New York University School of Medicine in New York City.
The future of prostate cancer monitoring
Long-term data attest to the safety of active surveillance for low-risk disease. For instance, a Canadian study published this year showed that only 1.5% of 993 men enrolled in an active surveillance protocol in 1995 had died of prostate cancer two decades later. The men were 69 years old on average when diagnosed. “But active surveillance is not just for older men,” Cooperberg emphasized. “Our data show that it can be effective in younger men too.”
Scientists are also looking for less invasive ways to monitor tumor progression — for instance, with imaging tests or more accurate markers in blood and urine. These alternative approaches could make active surveillance far less burdensome in time.
“Active surveillance serves as a middle-ground option,” said Dr. Marc Garnick, the Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center, and Editor in Chief of HarvardProstateKnowledge.org. “For example, men who are uncertain about considering PSA testing in the first place and who are concerned about overtreatment if they are diagnosed with prostate cancer may find the option of active surveillance attractive. That’s especially true given the lack of evidence that treating early-stage prostate cancer extends lives. Hopefully research will one day provide ways to predict if a given treatment will work based on the genetic makeup of a man’s tumor.”
This post was originally posted on our Harvard Prostate Knowledge website.
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