Sane Look at PSA and Mammography
Julian Whitaker, MD
Are you confused about whether to have a PSA test or a mammogram? Join the crowd. Everywhere you turn, there’s conflicting information about cancer screening. The American Cancer Society says one thing, and the US Preventive Services Task Force says another. Bureaucrats and politicians—who have no medical background whatsoever but are eager to appease—join the fray with impassioned pronouncements.
What gets lost in all this noise, which has reached a crescendo in recent months, are the hard facts about cancer screening. Let’s look at the latest scientific research on the pros and cons of the two most controversial tests: PSA for prostate cancer and mammography for breast cancer.
PSA Is an Inaccurate Test
Prostate-specific antigen (PSA) is an enzyme produced in the prostate. For the past two decades, men over age 50 have been recommended to have their blood level of PSA tested every year. If it’s higher than 4 ng/mL, they’re usually urged to have a biopsy or other evaluation.
This is nuts. PSA levels increase for many reasons. Infection, age-related prostate enlargement, even sex the night before the blood draw can raise PSA. Furthermore, 4 ng/mL is no magic number. Stanford University researchers conducted a study in which they compared preoperative PSA scores with postoperative tumor size and found that a PSA of 9 was no more predictive of a large, aggressive tumor than a score of 2.
Nevertheless, 30 million men in this country dutifully line up for their annual PSA tests. Last year, 192,000 of them were diagnosed with prostate cancer—and that’s when the real trouble begins.
Brutal Treatments, Lasting Side Effects
First, there’s the emotional burden of being told you have cancer. Even though prostate cancer is far from a death sentence—one in six American men will be diagnosed but only 3 percent of them will die from it—it’s terribly frightening. Worse still are the treatments. You’d think that because PSA values are an unreliable indicator of cancer, let alone tumor size and severity, physicians would proceed cautiously, order repeat tests, monitor patients, and take action only if levels continue to increase. This treatment philosophy, called watchful waiting, is the most reasonable approach to prostate cancer.
But that’s not what happens. Overdiagnosis leads to overtreatment, and overtreatment causes harm. The current mindset in oncology is to get it out fast, and most patients buy into that thinking. Conventional cancer therapies are brutal, and common side effects of the most popular interventions for prostate cancer (radical prostatectomy, radiation, and androgen deprivation therapy) include erectile dysfunction, urinary and fecal incontinence, and loss of muscle mass, bone density, and energy.
If routine PSA testing were helping men, I would be all for it. But according to the most recent studies, it’s not.
The Latest Studies on PSA
In a 2009 multicenter study published in the New England Journal of Medicine, researchers compared the outcomes of more than 76,000 men, ages 55 through 74, who were randomly assigned to have annual PSA tests plus digital rectal exams or “usual care.” After seven years of follow-up, there was a 22 percent increase in prostate cancer diagnosis in the screening group compared to the control, but no difference in the death rate from this disease. Screening clearly did not save lives.
A second study published in the same journal, involving 182,000 men of similar ages from seven European countries, did show a 20 percent reduction in the death rate—but that’s not as impressive as it may sound. Because there were so few deaths from prostate cancer (most tumors are very slow growing and don’t cause problems), the absolute difference was less than one (0.71) death per 1,000 men. The researchers calculated that 1,410 men would have to be screened for the disease and 48 of them would have to receive treatment in order to prevent just one person from dying.
They also emphasized the risks of overdiagnosis—diagnosis in men who, if not for PSA screening, would never have symptoms or be aware that they had cancer—and reported that it may be as high as 50 percent. In other words, all too often prostates are yanked out, testosterone levels are decimated, and quality of life is destroyed for nothing!
Breast Cancer Is Also Overdiagnosed
The latest research supporting routine breast cancer screening isn’t much different. Approximately 70 percent of women over age 40 report having had a recent mammogram. They accept the pain of the procedure, which I’ve heard jokingly referred to as like lying down on the driveway and letting a car run over your breast. They overlook the radiation exposure, which adds up with annual screenings and itself increases risk of cancer. Why? Because they’ve been convinced it’s their best defense against death from breast cancer. But is it?
Last year the Cochrane Collaboration, a well-respected international organization that reviews the science behind various medical interventions, looked at all the randomized clinical trials that compared mammography screening with no screening. The analysis included seven long-term studies and 600,000 women. Three of the studies showed that routine screening did not significantly reduce the death rate. Four studies, which the researchers said had “suboptimal randomization” (a design flaw), showed a significant reduction. The combined data revealed that screening mammography conferred a 15 percent reduction in risk of death. But it also led to 30 percent overdiagnosis and overtreatment, and the absolute risk reduction was just 0.5 percent.
The researchers concluded, “This means that for every 2,000 women invited for screening throughout 10 years, one will have her life prolonged and 10 healthy women, who would not have been diagnosed if there had not been screening, will be treated unnecessarily. Furthermore, more than 200 women will experience important psychological distress for many months because of false positive findings. It is thus not clear whether screening does more good than harm.”
The Dark Side of Screening
As this study makes clear, routine screening has a dark side. For every 100 women screened, 10 will be told their mammograms are suspicious and that they need additional testing. A woman who has a mammogram every year for 10 years has a 65 percent chance—more than one in two—of having at least one false positive.
Emotional trauma aside, this opens the door for biopsies and other tests, as well as treatment of tumors that would never amount to anything. The Cochrane group reported that significantly more of the women who had been screened had lumpectomies and mastectomies. The knee-jerk reaction is to assume that these procedures saved lives. Ask any woman who has undergone such a procedure, and she’ll likely agree. But she may well have had an “indolent” cancer, which studies suggest frequently regress and disappear on their own. These are the tumors that are far more likely to get picked up on yearly screening, not the aggressive, rapidly spreading cancers that are responsible for most breast cancer deaths.
Follow the Money
Folks, none of this is news. Since 1993, I’ve been warning about PSA and mammography’s propensity to funnel patients into unnecessary treatment. It’s only gotten worse with time. We now spend $20 billion every year screening for prostate and breast cancer. Why, despite all the scientific evidence, does this persist? Just follow the money.
The American Medical Association, the American College of Radiology, and the American Urological Association (AUA)—physician groups comprised of members who test for and treat prostate cancer—enthusiastically endorse screening. In fact, the AUA, which boasts 16,744 members, most of them urologists, updated their “Best Practice Statement” last year and lowered the recommended age for baseline PSA testing to 40!
Then there are the pro-screening organizations like the Prostate Conditions Education Council (PCEC, prostateconditions.org), which hosts the annual Prostate Cancer Awareness Week and organizes free PSA testing at hundreds of locations across the country. Guess who sponsors PCEC? Drug companies!
Mammography Critics Silenced
Conflicts of interest are even more blatant in the mammography industry. Late last year, the US Preventive Services Task Force (USPSTF) changed its recommendations for breast cancer screening to discourage routine mammography in 40- to 49-year-old women. The scientific basis for this is sound. More than 1,900 women in this age group would have to be screened for 10 years in order to prevent one death. The USPSTF also encouraged screening every other year, rather than annually, for women ages 50 to 74. Immediately, all hell broke loose.
The Chairwoman of the American College of Radiology Commission on Breast Imaging was quoted as saying these recommendations “place a great many women at risk of dying unnecessarily.” The president of the Society of Breast Imaging called them “…inconsistent with current science…many women may pay for this unsound approach with their lives.” A press release from the American College of Radiology predicted that this policy would “…turn back the clock on medicine for decades and needlessly reverse advances in cancer detection that have saved countless lives.”
See the pattern here? Talk about protecting your turf! These organizations and others position screening mammography as the responsible, almost patriotic thing to do. Heck, the United States Senate even got into the fray and actually passed an amendment in December to ensure coverage of screening mammography for women in their forties. The USPSTF was forced to back down and sugarcoat its very sensible stance. Meanwhile, the American College of Obstetricians and Gynecologists and the American College of Radiology have held firm in their mammography recommendations: every one or two years for women in their 40s and yearly for those 50 and older.
Don’t Be Scared Into Screening
The medical literature on prostate cancer screening is quite clear: It does not live up to its hype. Of course, PSA testing has its uses. PSA velocity, or the rate of increase—particularly following a diagnosis of cancer—is a useful tool for evaluating disease progression. But screening everybody and his brother is not a good use of our health care dollars and often does more harm than good.
The scientific data on screening mammography is a little murkier. Routine screening for women who are in their 40s or older than 75 has not been demonstrated to provide significant benefits. For asymptomatic women between the ages of 50 and 74, benefits are scant, and in my opinion, are outweighed by the risks of overdiagnosis and overtreatment.
Richard J. Ablin, the scientist who discovered PSA, said in a March 2010 Op-Ed piece in the New York Times, “I never dreamed that my discovery four decades ago would lead to such a profit-driven public health disaster. The medical community must confront reality and stop the inappropriate use of PSA screening. Doing so would save billions of dollars and rescue millions of men from unnecessary, debilitating treatments.”
And Otis Brawley, Chief Medical Officer of the American Cancer Society, also quoted in the New York Times, said, “We don’t want people to panic, but I’m admitting that American medicine has overpromised when it comes to screening. The advantages to screening have been exaggerated.”
- Am I telling you not to be screened? No. But I am telling you that the evidence of benefit is slight to nonexistent and in no way warrants the scare tactics that are widely used. Do your research and make your own decision based on facts, not fear.
- Ablin RJ. The great prostate mistake. New York Times. 2010 March 9.www.nytimes.com/2010/03/10/opinion/10Ablin.html. Accessed March 26, 2010.
- Andriole GL, et al. Mortality results from a randomized prostate-cancer screening trial. N Engl J Med. 2009 Mar 26;360(13):1310–1319.
- Fugh-Berman A, et al. Mammography and the corporate breast. Bioethics Forum. 2009 Nov 24. www.thehastingscenter.org/Bioethicsforum/Post.aspx?id=4194. Accessed March 28, 2010.
- Gøtzsche PC, Nielsen M. Screening for breast cancer with mammography. Cochrane Database of Syst Rev. 2009 Oct 7;(4):CD001877.
- Kolata G. Cancer Society, in shift, has concerns on screenings. New York Times. 2009 Oct 20. http://www.nytimes.com/2009/10/21/health/21cancer.html. Accessed March 27, 2010.
- Rhee F. Senate passes mammogram provision. Boston Globe. 2009 Dec 3.www.boston.com/news/politics/politicalintelligence/2009/12/senate_passes_m.html. Accessed March 27, 2010.
- Schröder FH, et al. Screening and prostate-cancer mortality in a randomized European study. N Engl J Med. 2009 Mar 26;360(13):1320–1328.
- Smith RA, et al. Cancer screening in the United States, 2010. A review of current American Cancer Society Guidelines and Issues in Cancer Screening. CA Cancer J Clin. 2010 Mar–Apr;60(2):99–119.
- Stamey TA, et al. Preoperative serum prostate specific antigen levels between 2 and 22 ng./mL correlate poorly with post-radical prostatectomy cancer morphology. J Urol. 2002 Jan;167(1):103–111.
- Zahl PH, et al. The natural history of invasive breast cancers detected by screening mammography. Arch Intern Med. 2008 Nov 24;168(21):2311–2316.
Modified from Health & Healing with permission from Healthy Directions, LLC. Photocopying, reproduction, or quotation strictly prohibited without written permission from the publisher. To subscribe to Health & Healing, click here.