(NCI), the major source of federal funding for cancer research in the United States, has developed a computerized information system called PDQ (Physician Data Query). The PDQ system provides doctors with the most current information on the treatment of cancer, the management of complications of cancer and its treatment and the early detection and prevention of the disease. It also contains up-to-date information on clinical trials designed to test new cancer detection, treatment and prevention approaches, a directory of doctors who treat cancer and a directory of facilities that have accredited early detection and/or cancer care programs.

How PDQ Is Organized  The PDQ system is composed of information that is organized in interconnected computer files that are stored in electronic form and make up a database.
    The information is organized and stored in electronic files for several reasons. First, computerized data files can be transmitted from one location to another over standard telephone line. Second, the files can be updated frequently with new treatment information; the PDQ files are updated every month. Third, the data files can be interlinked in such a way that users can retrieve information from different files concurrently with a simple command.