Cancer Screening Not Always Effective
April 5, 2002
Public health efforts to develop programs to screen newborns for inherited and congenital disorders began with the observation that severe mental retardation associated with phenylketonuria could be prevented in affected newborns. As a result, universal screening and tracking of newborns was implemented in the United States.
Since then, other screening and interventions have been added. However, determining which tests are appropriate has proven to be controversial. In the past, new tests have been included only if the disorder was an important health problem and if the screening tests were economical and effective. But which disorders meet those criteria?
For instance, a simple urine test for a rare, usually fatal, form of brain cancer was thought to hold promise. After testing newborns and infants in Germany and Quebec, the scientists found startling results.
- Neuroblastoma, the second most common cancer tumor in children, is found in about one of every 7,000 children under the age of 5.
- Researchers say that two-thirds of the cancers detected would have disappeared on their own; thus, those children were subjected to unnecessary and potentially harmful interventions.
- On the other hand, the test doesn't catch some advanced neuroblastomas; thus, despite early intervention, the death rate from neuroblastomas did not fall among children given the test.
According to experts, the neuroblastoma story was perhaps the clearest example of the hazards of screening. The same issues arise in all screenings, yet most such tests, including a blood test for prostate cancer and new tests for lung cancer, are being used before they have been evaluated.
Source: Woods et al., "Screening of Infants and Mortality Due to Neuroblastoma," New England Journal of Medicine, April 4, 2002; George Cunningham, "The Science and Politics of Screening Newborns," New England Journal of Medicine, April 4, 2002; Gina Kolata, "Screenings Found Harmless Tumors While Missing Deadly Cancers, New York Times, April 4, 2002.
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