miércoles, 21 de marzo de 2012

Updated European Prostate Cancer Screening Trial Data Show Little Change in Risk Reduction ► NCI Cancer Bulletin for March 20, 2012 - National Cancer Institute

NCI Cancer Bulletin for March 20, 2012 - National Cancer Institute

Updated European Prostate Cancer Screening Trial Data Show Little Change in Risk Reduction

After 11 years of follow up, results from a large European clinical trial continue to show a reduced risk of death from prostate cancer associated with prostate specific antigen (PSA) screening. The findings, from the European Randomized Study of Screening for Prostate Cancer (ERSPC) trial, show a 21 percent relative reduction in prostate cancer mortality among men who underwent routine PSA screening compared with men who did not—the same risk reduction previously reported after 9 years of follow-up.
Consistent with the earlier results, screening was also associated with important harms, Dr. Fritz Schröder of Erasmus University Medical Center and his colleagues reported March 15 in the New England Journal of Medicine. About half of those diagnosed on the basis of PSA screening were overdiagnosed—that is, diagnosed with prostate cancers that likely would never have threatened their lives.
Overall, the researchers found that 1,055 men would need to be invited for screening and 37 cancers would need to be detected to prevent one death from prostate cancer.
With approximately 182,000 participants, the eight-country ERSPC trial consortium is the largest randomized study of PSA screening for prostate cancer ever conducted. Earlier this year, 13-year follow-up results were published from the second-largest trial, the NCI-funded Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial of 77,000 men. In the PLCO trial, annual PSA screening did not reduce the risk of dying from prostate cancer. Screening did lead to substantial rates of overdiagnosis but lower than those in the ERSPC trial.
The conflicting results have been attributed to a number of key differences between the trials, wrote Dr. Anthony Miller of the University of Toronto in an accompanying editorial. The two trials used different PSA scores as a cutoff point and screened men at different intervals. The PLCO trial also had a substantial amount of “contamination”—more than half of men in the PLCO control arm underwent screening outside the trial. In addition, he pointed to evidence that there may have been different prostate cancer treatment in the screened versus control arms of the ERSPC study.
“We are left with an unsatisfactory situation, in which many practitioners will think there are insufficient data to recommend abandoning PSA screening for prostate cancer,” Dr. Miller wrote. Because the PLCO results are more applicable to clinical practice in the United States, Dr. Miller said it would be “advisable” to follow the recent draft recommendations Exit Disclaimer of the U.S. Preventive Services Task Force, which advise against PSA screening for prostate cancer among men considered to be at low risk of the disease.

Also in the Journals: Children and Adolescents with Acute Lymphoblastic Leukemia are Living Longer
An analysis of data from more than 21,000 children and adolescents treated for acute lymphoblastic leukemia (ALL) through clinical trials led by the Children's Oncology Group (COG) has found that 5-year survival rates rose from 83.7 percent between 1990 and 1994 to 90.4 percent between 2000 and 2005.
Survival improved among all children older than 1 regardless of age, sex, race or ethnicity, or ALL subtype. However, the relative risk of death varied among subgroups, with younger children faring better than adolescents, for example. Findings from the study, which includes the largest group of childhood ALL patients ever analyzed, were published online March 12 in the Journal of Clinical Oncology.
The study authors “believe that the major reason for improved survival [seen in this study] was decreased risk of relapse.” Survival rates for children with ALL have risen dramatically since the 1960s due to improved treatment regimens with existing chemotherapy drugs, noted lead author Dr. Stephen Hunger of the University of Colorado. “Future improvements will depend, in large part, on developing new drugs to treat the hard-to-treat subsets of childhood leukemia,” including infants less than a year old, Dr. Hunger said.

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