New Studies Show the Downside Of Cancer Screening
Doctors say screening can harm, but others say it still brings benefits.
Sept. 1, 2009— -- Recent years have seen a rise in encouragement for cancer screenings, but a number of studies have reminded physicians and their patients of the old saying about free lunches.
That is, nothing good comes without a cost.
Two studies released Monday -- one looking at prostate cancer and the other at breast cancer -- appearing in the Journal of the National Cancer Institute, show that increased screening brings false positives and the costs of emotional anguish and sometimes unnecessary treatment.
"The fact that it is a surprise to so many physicians and so many patients is a symptom of the debate taking place now regarding health care reform," said Dr. Thomas Schwenk, a family physician with the University of Michigan, commenting on the prostate cancer study. "The American approach to medical care is to always do more, irrespective of whether it has any value, and even in the face of data showing that doing more causes harm."
While the prostate cancer study, which utilized data from the National Cancer Institute (not affiliated with the journal that published the study), and the breast cancer study, which used data from women being screened in the province of Ontario, Canada, were in two different cancers in two different populations, both studies came to similar conclusions; in short, a lot of patients were receiving unnecessary treatments.
In the breast cancer screening study, women in Ontario were given a clinical breast exam in addition to mammography.
"I think that women should be informed of the benefits and limitations if they have a clinical breast exam in addition to mammography," said Anna Chiarelli, an epidemiologist at the University of Toronto and one of the authors of the breast screening study. "For every additional cancer found there were 55 false positives."
Meanwhile, according to the prostate cancer study's authors, between the years 1986 and 2005, 1 million "additional" men were diagnosed with prostate cancer.
"Given the considerable time that has passed since PSA screening began, most of this excess incidence must represent overdiagnosis," concluded Dr. H. Gilbert Welch, professor of medicine and community and family medicine at Dartmouth Medical School and Dr. Peter C. Albertsen, chief and program director of the division of urology at the University of Connecticut Health Center.
"It is of note that countries that do not have widespread screening as a policy have seen some declines in prostate mortality without the harm of frequent overdiagnosis," said Dr. Otis Brawley of the American Cancer Society in a related editorial.