PDQ is an online source of cancer information that is developed and maintained by the National Cancer Institute (NCI). It makes current, credible, and accurate cancer information available to health professionals and the public. PDQ contains information about cancer treatment, supportive and palliative care, screening, prevention, genetics, and integrative, complementary, and alternative medicine. This information is updated with the most recent evidence from scientific research. PDQ also contains drug information summaries on many cancer-related drugs; dictionaries of cancer terms, drug terms, and genetics terms; and a directory of professionals who provide genetics services. Most of this information and more specific information about PDQ can be found on the NCI's website at http://www.cancer.gov/publications/pdq. Also called Physician Data Query.