A comparison between the Rappaport Classification and Working Formulation in cooperative group trials: the ECOG experience.

The Working Formulation (WF) for the classification of non-Hodgkin's lymphomas was shown to be reproducible and clinically relevant in the original study. However, it has not yet been tested by an NCI-supported cooperative clinical oncology group. As a result, the Hematopathology Subcommittee of the Eastern Cooperative Oncology Group (ECOG) undertook a retrospective study to compare concordance and practical utility between the WF and the Rappaport Classification (RC). Data indicate that with appropriate modifications to minimize unclassifiable lymphomas, the WF can be effectively utilized in cooperative clinical oncology groups.