The number of older Americans treated for prostate cancer plummeted 42 percent since health officials began questioning the benefits of screening tests, a new study shows.
The finding points to the success of efforts to curtail the use of controversial prostate-specific antigen, or PSA, screening tests, said lead author Dr. Tudor Borza.
At the same time, his team found, doctors still face challenges trying to convince men diagnosed with early-stage prostate cancer to watch and wait before undergoing surgery or other invasive treatment, Borza said.
From 2007 to 2012, Medicare data showed a relatively meager 8 percent drop in the number of men who were treated immediately after a prostate cancer diagnosis, Borza's team reports in Health Affairs.
Borza, a urologist and research fellow at the University of Michigan Health System in Ann Arbor, said he feared the statistics might mean that too few men are being screened, and among those who do get a prostate cancer diagnosis, too few are following the strategy of watchful waiting and surveillance recommended by urologists for early-stage tumors.
"I believe more men should be screened," Borza said in a phone interview. "A diagnosis of prostate cancer shouldn't necessarily lead to treatment."
A PSA test measures the amount of a protein known as prostate-specific antigen in a man's blood. Often, however, the test falsely signals possible cancer, causing anxiety and leading to unnecessary, invasive and sometimes debilitating procedures.
Moreover, many men are likely to die of other causes before slow-growing prostate cancer harms them. But once they've been diagnosed with prostate cancer, men frequently elect to be treated and can suffer punishing side effects, including impotence and incontinence.
"Diagnosis has a way of begetting treatment, whether or not it warrants treatment," said Dr. Gilbert Welch, professor of medicine at the Dartmouth Institute for Health Policy and Clinical Practice in Lebanon, New Hampshire. He was not involved with the new study.
"Patients think once cancer is there, you've got to act," Welch said in a phone interview. "The question is whether you want to be looking for early forms of cancer."
Borza and Welch both believe the decision should be left to individual men. But the two physicians approach the question from differing perspectives. Borza's interest in continuing to screen men for prostate cancer with PSA tests generally aligns with other urologists, and Welch's preference for less screening aligns with other primary-care physicians.
In 2008, the U.S. Preventive Services Task Force (USPSTF) advised against routine PSA testing of men older than 75. By 2011, the government-backed panel of independent physicians recommended against all PSA screening, warning that the benefits do not outweigh the harms.
The American Urological Association, however, recommends that men weigh the benefits and harms of PSA screening in conversations with their doctors and finds the greatest value to screening in 55 to 69 year olds.
Borza and his team analyzed Medicare data and identified more than 67,000 men age 66 and older who were diagnosed with prostate cancer between 2007 and 2012. During the same period, the population-based rate for men treated for prostate cancer dropped 42 percent, from 4.3 per 100,000 men to 2.5 per 100,000, the study shows.
Nearly three-quarters of the men diagnosed with prostate cancer had curative treatment, such as surgery or radiation, within a year, while 17 percent instead opted for "watchful waiting" or "active surveillance," the study found.
Most of the men diagnosed with prostate cancer were between 66 and 75 years old, but nearly 16 percent were 80 and older - too old to likely benefit from treatment, according to the USPSTF guidelines.
Men are much more likely to die with prostate cancer than from it, Welch said.
"The question is whether you want to be looking for early forms of cancer," he said. "There's no limit to how much data we can collect, but that doesn't mean we want all that information. It can lead people down a rabbit hole."
Borza sees it differently.
"Information is power," he said. "Knowing where you stand allows you to make the best decisions."
Nonetheless, he acknowledges that deciding whether and how to treat an early-stage prostate cancer diagnosed after a PSA test can be an agonizing decision. And no one can say how many lives might be saved by treating those cancers.
Borza recommends men consider getting PSA tests at 50 years old. But, he said, "It is a very difficult decision for a man to make. There's not a great answer."