physician data query physician data query physician data query (pdq) is the us national cancer institute's (nci) comprehensive cancer database. it contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, and supportive care, and complementary and alternative medicine; a registry of more than 6,000 open and 17,000 closed cancer clinical trials from around the world; and a directory of professionals who provide genetics services. a woman accessing the pdq database with an early laptop in 1987 pdq makes available two data resources. the pdq nci cancer terms database is a resource of cancer-related terms, curated by a multidisciplinary panel of reviewers, that is released monthly. the nci drug dictionary is a structured list of technical definitions and synonyms for drugs/agents used to treat patients with cancer or conditions related to cancer. the nci also makes a browse-able version of the cancer terms database available as part of the nci terminology browser