Prostate cancer screening with prostate-specific antigen (PSA) afforded no obvious prostate cancer mortality benefit during 13 years of follow-up in a large randomized trial.
In fact, screened patients had a slightly higher prostate cancer mortality: 3.7 per 10,000 person-years, versus 3.4 for unscreened men.
The results emphasize the need to find some means to identify patients who are most likely to benefit from PSA screening, said the first author of a report in the January issue of the Journal of the National Cancer Institute.
"Routine mass screening of the population, purely on the basis of a man's age, is not going to be an effective way of reducing his chance of dying of prostate cancer," Gerald Andriole, MD, of Washington University in St. Louis, told MedPage Today.
"Having said that, that's not to say that no man should get PSA testing," he continued. "There are subsets of men in the population at large who do seem to stand a good chance of benefiting from PSA testing.
"Those are men who are young, with no comorbidities, and generally very healthy. These are men with the longest life expectancy overall. They are men who, even if they harbor a nonaggressive, slow-growing cancer, are nonetheless expected to live long enough to die of prostate cancer in the absence of it being identified and treated."
Screening also is reasonable for men who have an above-average risk of prostate cancer, such as African Americans and men with a strong family history of the disease, Andriole added.
The data 0ffered nothing to change the conclusions of
an earlier analysis of data from the same study, the National Institutes of Health-sponsored Prostate, Lung, Colorectal, and Ovarian (PLCO) screening program. After a median follow-up of seven years (up to as long as 10 years) the screened and unscreened groups had a similar prostate cancer mortality.
The prostate cancer portion of PLCO involved 76,685 men who were ages 55 to 74 and cancer-free at enrollment. Study participants were randomized to annual PSA screening for six years or to usual care, which sometimes included "opportunistic" PSA screening.
The initial report from the study showed a prostate cancer rate of 116 per 10,000 in the screened group compared with 95 per 10,000 in the control group. Prostate cancer mortality was 2 per 10,000 with screening and 1.7 per 10,000 in the control group.
The current report showed that after a median follow-up of 13 years, cancer incidence was 108.4 and 97.1 per 10,000 in the screened and unscreened groups, respectively. The difference represented a statistically significant 12% increase in cancer incidence in the screened group (RR 1.12, 95% CI 1.07 to 1.17).
Mortality was 3.7 and 3.4 per 10,000 with and without screening, respectively, a nonsignificant difference.
"This article updates with more person-years of follow-up our previously reported finding of no reduction in mortality from prostate cancer in the intervention arm compared with the control arm to 10 years, with no indication of a reduction in prostate cancer mortality to 13 years," the authors wrote of their findings.
Responding to the study, Otis W. Brawley, MD, chief medical officer of the American Cancer Society, acknowledged that the results are consistent with other studies that have pointed to a potential harm from overscreening and unnecessary treatment of indolent prostate cancer.
"This trial does suggest that if there is truly an advantage to mass [PSA] screening it is small," Brawley said in a statement.
Even so, the results do not rule out the possibility of a benefit in some high-risk men or the value of PSA screening in men who want the test, he added.
"I truly believe that a man who is concerned about prostate cancer and understands that experts are not certain that screening saves lives, but it definitely causes anxiety and needless treatment, can reasonably choose to be screened," said Brawley.
"A man who is more concerned with unnecessary diagnosis and treatment might reasonably choose not to be screened. It is an area that needs to be left to an informed patient."
The PLCO trial is sponsored by the National Institutes of Health.
Andriole disclosed relationships with Amgen, Augmenix, Bayer, Cambridge Endo, Caris, France Foundation, GenProbe, GlaxoSmithKline, Myriad Genetics, Steba Biotech, Ortho Clinical Diagnostics, and Viking Medical. Co-authors disclosed relationships with GlaxoSmithKline and Human Genome Sciences.
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