Cancer screening called 'a double-edged sword'
HANOVER, NH - The public is committed to cancer screening, even with false-positive results or the possibility that testing could lead to unnecessary treatment, according to a Dartmouth Medical School (DMS) study in the January 7 issue of The Journal of the American Medical Association (JAMA). Such enthusiasm could put the public at risk for "overtesting and overtreatment" of certain cancers, warn the researchers.
"There is growing recognition among medical professionals that cancer screening is a double-edged sword," write the investigators who include Drs. Lisa M. Schwartz and Steven Woloshin, associate professors of medicine at DMS and Dr. Gilbert Welch, professor of medicine at DMS, all of whom are physicians based at the VA Medical Center in White River Junction, VT. "While some individuals may benefit from early detection, others may only be diagnosed and treated for cancer unnecessarily. The public needs access to balanced information about its [cancer screening] potential benefits and harms."
The researchers, led by Schwartz and Woloshin, conducted national telephone interviews with 500 adults during 2001 and 2002 to learn about experience with a broad range of screening tests. The survey included 360 women aged 40 years or older and 140 men aged 50 years or older without a history of cancer. It encompassed questions about the value of early detection; and four cancer screening tests: Papanicolaou (Pap); mammography; prostate-specific antigen (PSA); and sigmoidoscopy or colonoscopy.
"Most American adults (87 percent) feel routine cancer screening is almost always a good idea," the investigators found. "Seventy-four percent believe that finding cancer early saves lives 'most' or 'all of the time.' Fifty-three percent believe screening usually reduces the amount of treatment needed when cancer is found."
The authors, who include members of the VA Outcomes Group and the Norris Cotton Cancer Center at Dartmouth, report that, "Less than one third believe there will be a time when they will stop undergoing routine screening. A substantial proportion believe that an 80-year-old who chose not to be tested was irresponsible: ranging from 41 percent with regard to mammography to 32 percent for colonoscopy. Thirty-eight percent of respondents had experienced at least one false-positive screening test; more than 40 percent of these individuals characterized that experience as 'very scary' or the 'scariest time of my life.'" Still, 98 percent of those respondents were glad they had the initial screening test, the research found.
Most respondents wanted to know about the presence of a cancer, regardless of its implications: two-thirds said they would want to be tested for a cancer even if nothing could be done; and 56 percent would want to be tested for "pseudodisease," cancers growing so slowly that they would never cause problems even if untreated.
Moreover, the researchers report great interest in the total body computed tomographic (CT) screening, although no data support its benefit or safety, and it is not endorsed by any professional medical organization. Almost 75 percent of those surveyed would choose a total body CT scan over receiving $1,000 in cash.
"Some clinicians will see our results as welcome evidence of the success of public health campaigns for widely recommended cancer screening tests," the researchers write. "Others 'will see disturbing evidence that these same campaigns have communicated a misleadingly simple and one-sided message' a message that discourages meaningful discussions about the use of these tests in settings when the recommendations are less clear (e.g., screening at younger ages, at advanced age, or for individuals with multiple comorbidities [illnesses]." The public is primed to believe that there is value in having any test that is marketed as being able to find early cancer, suggest the authors. They conclude, "The challenge now is to balance messages and reduce the public's risk for overtesting and overtreatment."
The findings are limited, the researchers caution, because they do not know whether the public's enthusiasm for early detection would change if the potential benefits and harms of screening were fully communicated and understood.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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