A cancer registry is a systematic collection of data about cancer and tumor diseases. The data are collected by Cancer Registrars. Cancer Registrars capture a complete summary of patient history, diagnosis, treatment, and status for every cancer patient in the United States, and other countries. The Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute (NCI) was established in 1973 as a result of the National Cancer Act of 1971. The National Program of Cancer Registries (NPCR) was established by Congress through the Cancer Registries Amendment Act in 1992, and administered by the Centers for Disease Control and Prevention (CDC). NPCR and SEER together collect cancer data for the entire U.S. population. CDC and NCI, in collaboration with the North American Association of Central Cancer Registries, have been publishing annual federal cancer statistics in the United States Cancer Statistics: Incidence and Mortality report. Information maintained in the cancer registry includes: demographic information, medical history, diagnostic findings, cancer therapy and follow up details. The data is used to evaluate patient outcome, quality of life, provide follow-up information, calculate survival rates, analyze referral pattern, allocate resources at regional or state level, report cancer incidence as required under state law, and evaluate efficacy of treatment modalities. There exist population-based cancer registries, hospital cancer registries (also called hospital-based cancer registries), and special purpose registries. History In 1926, Yale-New Haven Hospital became the first to set up a cancer registry. In 1956, the American College of Surgeons (ACoS) formally adopted a policy to encourage, through their Approvals Program, the development of hospital-based cancer registries. In 1973, The Surveillance, Epidemiology and End Results (SEER) Program of NCI establishes the first national cancer registry program. In 1992, U.S. Public Law 102-515 establishes the National Program of Cancer Registries (NPCR) and is administered by the US Centers for Disease Control and Prevention (CDC).. By 1993, most states considered cancer a reportable disease. Types Population-based cancer registry Population-based cancer registries monitor the frequency of new cancer cases (so-called incident cases) every year in well defined populations and over time by collecting case reports from different sources (treatment facilities, clinicians and pathologists, and death certificates). The frequency of these incident cases are expected per 100,000 of the mother population. If an unexpected accumulation can be observed, a hypothesis about possible causes is generated. This hypothesis is investigated in a second step by collecting more detailed data. The