A blood test that is currently used to screen for prostate cancer leads to frequent overdiagnosis, and this prompts men to undergo invasive treatments that harm them with painful and often life-altering side effects like impotence and incontinence.
Those were the findings of an investigative panel convened to advise federal authorities on the test’s efficacy. The panel’s report was publicized in October last year (2011).
Prostate cancer treatments leave many survivors with erectile dysfunction, incontinent, and with difficulty urinating and controlling bowel functions, says the U.S. Preventive Services Task Force (USPSTF) in its report, published in the Annals of Internal Medicine.
And patients are prompted to undertake treatments — surgery, radiation or hormone therapies — by a blood test designed to detect higher than normal levels of prostate-specific antigen, or PSA, in the blood, the experts say.
The PSA test has become increasingly controversial as more doctors and studies cast doubt on its effectiveness.
For one, a high PSA level can signal prostate cancer but it can also indicate conditions that are more benign.
Now the USPSTF says that at least a fifth to 30 percent of all men who get radiation therapy or surgery experience incontinence and impotence. For its report, the panel analyzed five of the largest studies on the PSA tests.
What’s worse, the experts’ panel said that in one European study it analyzed, the rate of overdiagnosis from PSA screening was estimated to be as high as 50 percent. Based on that study, if 1,410 men are screened, 48 will be found candidates for treatment — but just one life will be saved from prostate cancer.
A recent Johns Hopkins University study even found surprisingly high rates of hospitalization for bloodstream infections after prostate biopsies and a 12-fold greater risk of death in those who develop these infections.
The USPSTF concludes: the benefits of the PSA test appears minimal, while the downsides are considerable. “The vast majority of men who are treated do not have prostate cancer death prevented or lives extended from that treatment, but are subjected to significant harms,” it says.
“There are clearly people we harm with therapy,” Dr. Bruce Roth, professor of medicine at Washington University in St. Louis tells Madison Park of CNN. “I don’t think there’s doubt about that. We wouldn’t be having this conversation if the therapy was nontoxic.”
Yet the public perception is that if PSA testing finds a cancer early, this must be good. And many prostate cancer survivors swear by the test and subsequent treatments.
For sure, there’s no overarching consensus on PSA testing today. Dr. Pat Walsh of Johns Hopkins University, a world-renowned urologist and pioneer in nerve-sparing prostate surgery, tells ABC news he thinks the panel’s recommendation is “a shame.”
“This decision ignores the fact that there has been a 40 percent reduction in prostate cancer deaths over the past 10 years since PSA testing has been in place,” Walsh says. “The USPSTF ignores this because it relies only on randomized trials, and there are a number that have too short a follow-up and other serious deficiencies.”
Dr. Leonard Gomella, chairman of urology at Thomas Jefferson University, called the decision an “appalling affront to all men who will die from prostate cancer.”
Dr. William Catalona, the Clinical Prostate Cancer Program at Northwestern Memorial Hospital director believes “the extent to which PSA screening causes over diagnosis and overtreatment is exaggerated.”
“I have to wonder whether economics are playing a role in the decision of the Task Force,” Dr. Jerome Richie, chief of urology at Brigham and Women’s Hospital tells ABC News.
And even the clinical director of the Massachusetts General Cancer Center, Dr. Bruce Chabner, who himself underwent treatment for prostate cancer detected at age 59, told ABC News the test may have been crucial for him.
“Would I still be alive and free of disease without PSA and treatment? I don’t know, but I suspect that at the very least I would not be free of metastatic disease,” Chabner said.
After reviewing existing evidence, the panel released a draft recommending that doctors stop relying on PSA testing.
In its report, the panel says:
• There’s “convincing evidence” that “PSA-based screening leads to substantial overdiagnosis of prostate tumors.”
• There was “small or no reduction” in prostate cancer deaths brought by the tests.
• The test is also “associated with harms related to subsequent evaluation and treatments.”
The main reason behind this is that the majority of men who have prostate cancer have a tumor that “will not progress or is so indolent and slow-growing that it will not affect the man’s lifespan or cause adverse health effects, as he will die of another cause first.”
The key to treatment then is not early diagnosis, but a news test to distinguish which patients have the quick, harmful cancers and which have the slow, harmless ones.
“The Holy Grail of prostate cancer research is to figure a test that can tell the difference between a relatively indolent cancer and one that will grow and kill the patient,” says Dr. Scott Eggener, assistant professor of surgery at the University of Chicago.
Not much of a killer
After all, most men who have prostate cancer are “destined to not die from it,” says Dr. Roth, who specializes in oncology. He says prostate cancer patients are more likely to die of more common causes like stroke or heart attack.
The actual lifetime risk of dying from prostate cancer is 2.8 percent and this form of cancer is rare at age 50 and younger, the National Cancer Institute says. Most deaths from prostate cancer occur in men who are 75 or older.
In most cases, doctors find that even just active surveillance — or holding off active treatment and just monitoring the patient — can be enough.
But the task force report found that about 90 percent of men undergo early treatment with surgery, radiation or hormone therapy.
Some patients understand and agree with this called “watchful waiting,” but most men are uncomfortable with the idea of living with cancer, it explains.
“There are people who never sleep again until they get some therapy,” Dr. Roth says. “They think about cancer growing and not doing something. You have to let patients make that decision for themselves and do what they feel most comfortable doing.”
Several non-urologists have applauded the USPSTF’s advice.
“I think this recommendation is long overdue,” said Dr. Thomas Schwenk, dean of the University of Nevada School of Medicine.
“This advisory mirrors my advice to patients over the last 10 years,” said Dr. William Golden, professor of medicine and public health at the University of Arkansas for Medical Sciences. “I have long believed that prostate cancer had a cure worse than the disease.”
Dr. Roth says science hasn’t caught up, and can’t yet distinguish between killer and slow-growing prostate cancers.
“Our hope is someday we can figure out, by some biomarker, by some genetic profiling, that would tell us who’s going to have an aggressive tumor,” he says.
What you should know about PSA tests
Does PSA show cancer?
No. PSA is just a measure of inflammation, which can be elevated for many reasons other than—normal enlargement of the prostate with age, an infection, a strenuous bike ride, horseback riding and even recent sex.
Have the PSA tests been proven to save lives?
Not really. Only two large, well-done studies have looked at this, the task force says. The American study found annual screening did not lower the chances of dying of prostate cancer.
But because cancer fear is so great and belief in screening so ingrained, half the men assigned to the group not offered PSA tests got one anyway. This made comparisons to the group given annual screening difficult—and because of this some doctors believe the study’s conclusions are not credible.
The other study, conducted in Europe, found a small benefit for certain age groups screened not annually—but every two to seven years. One Swedish center had such rosy results that scientists think it may have biased the whole study. Excluding the results from that center, the analysis shows no benefit from the PSA test.
Do the task force’s new findings go against past advice?
Not really. Some urologists and advocacy groups have supported routine PSA testing, but this has not been pushed by major scientific groups, U.S. health authorities or the American Cancer Society.
Do the PSA tests finds cancer early enough so you’re more likely to survive?
No. About 90 percent of prostate cancers found through screening are early-stage—and most will grow so slowly they will never threaten a man’s life. The hitch is that there’s no good way to tell which ones will.
What are the treatment options if I test positive?
Radical prostatectomy. In this procedure, surgeons remove the prostate gland. This has a 20 percent increased absolute risk of urinary incontinence and a 30 percent increased absolute risk of impotence compared with watchful waiting, the task force reports.
Radiation therapy. In this treatment option, cancer cells are killed using energy beams directed at the tumor or by radioactive seeds planted into patients’ prostates. But this procedures are associated with bowel dysfunction and rectal pain.
Hormone therapy. When the tumor is spreading, this is used to shrink the tumor, but not cure the cancer. Since prostate cancer cells rely on testosterone, the patient receives drugs that prevent the body from producing these hormones. But often, long-term hormone treatment causes weight gain and cardiovascular risks such as unexpected death, heart attack and higher rates of diabetes.