An approach to conducting epidemiologic research within cooperative clinical trials groups.

Cooperative clinical trials groups offer exciting opportunities for conducting epidemiologic research for several reasons: they facilitate accrual of sufficient numbers of subjects in a short period of time, even for studies of rare diseases; they provide uniform pathologic review and uniform collection of subjects' entry data; and they provide a more representative sample of cases than a single-institution study. Despite these advantages, few epidemiologic studies of etiologic factors have been done through these groups because methods for selecting appropriate control subjects and for obtaining information from geographically scattered subjects have not been available. An approach that can serve as a model for this type of research has been developed. A collaborative case-control study of childhood rhabdomyosarcoma (RMS) with the Intergroup Rhabdomyosarcoma Study (IRS) was recently begun. The study, which is independently funded, evaluates the role of environmental factors in the etiology of RMS. Parents of subjects were interviewed by telephone and control subjects were selected from the same communities as patients by random digit dialing . Interview data are supplemented by information from birth certificates and, for patients, by IRS data. This new methodology permits a large study of a rare tumor in a relatively short period of time.