New findings from a two-decade-long clinical trial of Swedish prostate cancer patients will likely fuel the debate over the best way to treat men diagnosed with early, slow-growing tumors.
The study, conducted by resesearchers from Sweden and the Harvard School of Public Health, found that men under age 65 who had their prostate glands surgically removed were less likely to die from their cancers than those who weren’t treated unless their cancers progressed—a strategy called watchful waiting. This approach has become popular because surgery and radiation treatments for prostate cancer frequently cause lifelong debilitating side effects such as urinary incontinence and erectile dysfunction.
Older men who had surgery didn’t have a lower risk of dying from prostate cancer but had a very small reduced risk of having their cancer spread to other organs.
“Prostate cancer has a very long natural history, and our results show that benefits of treatment become more pronounced with extended followup,” said study co-author Jennifer Rider, an assistant professor of epidemiology at Harvard.
But the results, published Wednesday in the New England Journal of Medicine, appear to contradict what other researchers found in a 2012 trial of US patients: men with early-stage prostate cancers, regardless of their age, enjoyed no life-extending benefits from immediate surgery instead of monitoring when tracked for an average of 10 years. In that trial, called Pivot, most men were diagnosed via a prostate specific antigen screening blood test—about a decade earlier than the Swedish men, who weren’t screened with the PSA test.
So the patients in the two studies were quite different, and the latest findings may not apply to the US population, where PSA screening is widespread because it was recommended until recently for men 50 and over.
“These men in Sweden were largely diagnosed the old fashioned way through a lump felt on a digital rectal exam” and likely had more advanced disease, said Dr. Michael Barry, president of the Informed Medicial Decisions Foundation who helped conduct the Pivot trial.
“I think this is an important study, but I’m cautious about its conclusions,” said Dr. Philip Kantoff, vice chair of the deparment of medical oncology at Dana-Farber Cancer Institute who was not involved with the Swedish research. “This is speculation, of course, but I would say the benefits of performing immediate surgery in men with low-risk cancers would probably go away if they had been screened with PSA.”
Prostate cancer is the second most common cancer among US men, and the second leading cause of cancer death.
The new study involved 695 men with early prostate cancer who were tracked, on average, for 13 years. Some were followed as long as 23 years. The researchers reported that 18 percent of the men under 65 who were treated with surgery had died of prostate cancer by the end of the study compared with 34 percent of men who were in the watchful-waiting group. Four men needed to be treated in order to prevent one prostate cancer death.
Results reported by the researchers a decade earlier found more modest life-saving benefits of immediate treatment. The authors said the new results reflect the fact that early prostate cancers generally take decades to kill and support the widespread practice of doctors gearing treatment recommendations to patients’ life expectancy: Those expecting to live more than about 20 years should consider more aggressive treatment.
“With longer followup, we’re seeing some improvements in treatment,” said Dr. Otis Brawley, chief medical officer of the American Cancer Society. “But even when we look at men in this study with more advanced disease, we find that there’s a host of men who don’t need to be treated.”
Reducing over-treatment in men with low-risk disease has been a growing priority among leading cancer centers in recent years.
Dana-Farber and other cancer centers now routinely offer what they call “active surveillance”—a version of watchful waiting that involves monitoring PSA levels and yearly prostate biopsies—to men over age 65 with early, non-agressive cancers that are unlikely to ever kill them. “Many of us are opening up to active surveillance in younger men, even those younger than 55,” Kantoff said. “I grapple with having an age cut off.”
Prostate cancer experts who spoke with the Globe all agreed that there’s no reason for that trend to reverse based on the new research finding.
“I don’t think this study changes my opinion,” said Dr. Ballentine Carter, a professor of urology and oncologist at Johns Hopkins School of Medicine. “The tools that we have today for assessing whether someone has a life-threatening disease are better than those used in the Swedish study.” Like Kantoff, he also uses active monitoring in younger men who have a personal preference to delay treatment, but added that he’s “a lot more enthustiastic” about it when a 50-something man has a “very low risk disease.”