The Will Rogers phenomenon: Roping the effects of a new cancer staging system.

Abstract

At least in some cases, historical controls may become history, thanks to the recent changes in a national set of cancer staging guidelines. A large study has shown that using the new American Joint Committee on Cancer (AJCC) staging guidelines—in place as of January 2003—results in dramatic artifactual improvements in stage-specific survival among women with locally advanced breast cancer. Although unlikely to affect treatment decisions, the findings suggest that comparing the results of current clinical trials to historical controls may result in misleading benefits.