The unexpected similarity between the participants with a negative and a false positive screen result is not because getting a false positive diagnosis is at all pleasant, Gareen said, but presumably because study participants understood that there was a high likelihood of a false positive screen result.
"We think that the staff at each of the NLST sites did a very good job of providing informed consent to our participants," she said. "In advance of any screening, participants were advised that 20 to 50 percent of those screened would receive false positive results, and that the participants might require additional work-up to confirm that they were cancer free."
To make its assessments, Gareen's team surveyed 2,812 NLST participants for the study. Patients responded well, with 2,317 returning the survey at one month after screening and 1,990 returning the survey at six months. The survey included two standardized questionnaires: the 36-question Short Form SF-36, which elicits self-reports of general physical and mental health quality, and the 20-question Spielberger State Trait Anxiety Inventory.
Maryann Duggan and her staff from the Outcomes and Economics Assessment Unit at Brown administered the questionnaires by mail with telephone follow-up as required.
In the study analysis, the researchers divided people into groups based on their ultimate accurate diagnoses: 1,024 participants were "false positive," 63 were "true positive," 1,381 were "true negative" and 344 had a "significant incidental finding," meaning they didn't have cancer but instead had another possible problem of medical importance.
The results were clear after statistical adjustment for
|Contact: David Orenstein|