Prostaatkanker opsporing niet altijd zinvol*
Als gevolg van verschillende wetenschappelijke onderzoeken wordt in Amerika aan artsen het advies gegeven om mannen vanaf hun 75ste jaar niet standaard meer te testen op
prostaatkanker. Recentelijk was er nog een tienjarig Zweeds onderzoek waaruit bleek dat het voor mannen van 65 jaar en ouder het geen verschil in overlevingskans maakten of
ze nu behandeld werden dan wel alleen gecontroleerd werden. Behandelingen kunnen
vaak nare gevolgen hebben. Prostaatkanker is de meest voorkomende kankersoort bij mannen. Gek genoeg is prostaatkanker niet nummer 1 op het gebied van doodsoorzaken. Veel meer mannen overlijden namelijk aan longkanker en dikke darm kanker. Prostaatkanker staat als doodsoorzaak op nummer 3. Prostaatkanker groeit vaak langzaam zodat het merendeel van de mannen er geen last van krijgen. Meestal wordt de ziekte bij hen niet ontdekt. Soms komt de ziekte bij toeval aan het licht, bijvoorbeeld tijdens een medische keuring.
Prostaatkankerpatiënten van 70 jaar oud die als gezond worden beschouwd, leven gemiddeld nog 18 jaar. Patiënten van 70 die als zwak worden beschouwd, leven gemiddeld nog 7 jaar.
In a move that could lead to significant changes in medical care for older men, a national task force on Monday recommended that doctors stop screening men ages 75 and older for prostate cancer because the search for the disease in this group was causing more harm than good.
The guidelines, issued by the U.S. Preventive Services Task Force, represent an abrupt policy change by an influential panel that had withheld any advice regarding screening for prostate cancer, citing a lack of reliable evidence. Though the task force still has not taken a stand on the value of screening in younger men, the shift is certain to reignite the debate about the appropriateness of prostate cancer screening at any age.
Screening is typically performed with a blood test measuring prostate-specific antigen, or PSA, levels. Widespread PSA testing has led to high rates of detection. Last year, more than 218,000 men learned they had the disease.
Yet various studies suggest the disease is “overdiagnosed” — that is, detected at a point when the disease most likely would not affect life expectancy — in 29 percent to 44 percent of cases. Prostate cancer often progresses very slowly, and a large number of these cancers discovered through screening will probably never cause symptoms during the patient’s lifetime, particularly for men in their 70s and 80s. At the same time, aggressive treatment of prostate cancer can greatly reduce a patient’s quality of life, resulting in complications like impotency and incontinence.
Past task force guidelines noted there was no benefit to prostate cancer screening in men with less than 10 years left to live. Since it can be difficult to assess life expectancy, it was an informal recommendation that had limited impact on screening practices. The new guidelines take a more definitive stand, however, stating that the age of 75 is clearly the point at which screening is no longer appropriate.
The task force was created by Congress and first convened in 1984 to analyze current medical research and to make recommendations about preventive care for healthy people. Its guidelines are viewed as highly credible and are often relied on by physicians in making decisions about patient care.
“When you look at screening, you have a chance the screening will help you live longer or better, and you have the chance that screening detection and treatment will harm you,” said Dr. Ned Calonge, chairman of the task force and chief medical officer for the Colorado Department of Public Health and Environment. “At age 75, the chances are great that you’ll have negative impacts from the screening.”
It is estimated that one out of every three men 75 and older is now screened for prostate cancer, although some studies suggest the number is even higher. The Journal of the American Medical Association reported in 2006 that in a group of nearly 600,000 older men treated by the Veterans Administration, 56 percent of those ages 75 to 79 had been screened for prostate cancer. Given the large numbers of men over 75 who are being screened, even a small decline in testing may greatly reduce the number of prostate cancer cases detected.
Dr. Calonge said it was important that the guidelines not be viewed as “giving up” on older men. While the new rules should discourage routine testing of older patients, the recommendations will not prevent a man from seeking screening if he desires it, Dr. Calonge said. The new guidelines are not expected to alter Medicare’s current reimbursement for annual PSA screening of older men.
“There will be some men who would say, ‘Let’s do it anyway,’ and other men who say, ‘If we don’t need to do it, let’s not do it,’ ” Dr. Calonge said.
The guidelines focus on the screening of healthy older men without symptoms and will not affect treatment of men who go to the doctor with symptoms of prostate cancer, like frequent or painful urination or blood in the urine or the semen.
Studies of the value of prostate cancer screening for younger men have produced mixed results, but a major clinical trial under way in Europe will try to determine whether there is any value, in terms of longer life expectancy, to screening this group for prostate cancer. Those results may be published as early as next year.
While the verdict is still out on younger men, the data for older men are more conclusive, experts say. The American Cancer Society and the American Urological Association both say annual PSA screening should be offered to average-risk men 50 and older, but only if they have a greater than 10-year life expectancy.
Recently, Swedish researchers collected 10 years of data on men whose cancer was diagnosed after the age of 65 and found no difference in survival among those who were treated for the disease and those whose cancers were monitored but treated only if the cancer progressed. The finding suggests that for most men, stopping screening at 75 is a safe option.
“If someone has made it to the age of 75 and they don’t have an elevated PSA, the likelihood of them developing clinically significant prostate cancer in the last 10 to 15 years of their life is pretty low,” said Dr. Peter C. Albertsen, professor of urology at the University of Connecticut Health Center. “The downside risk begins to outweigh the upside at the age of 75.”
Some studies suggest that as many as half of men 75 and older have clinically insignificant prostate cancer that is unlikely to affect their health but may be found through a biopsy. If the disease is detected as a result of screening, the men may be actively treated with radiation or hormone therapies, or may endure the stress of “watchful waiting” to see if the disease progresses.
Treatments for prostate cancer can cause significant harm, rendering men incontinent or impotent, or leaving them with other urethral, bowel or bladder problems. Hormone treatments can cause weight gain, hot flashes, loss of muscle tone and osteoporosis.
“I’m very pleased the prevention task force has said, at least for the old guys, ‘Leave them alone because our evidence suggests it doesn’t help,’ ” said Dr. Derek Raghavan, director of the Cleveland Clinic Taussig Cancer Institute. “Taking an 80-year-old and telling him he has cancer and telling him he needs radiotherapy or surgery uses up medical resources and puts him at risk. It’s a step toward rational thinking.”
(Augustus
2008)
