The Rare Disease Act of 2002 (HR 4013) and the US Orphan Drug Act defines a rare disease or condition as one that "(A) affects less than 200,000 persons in the United States, or (B) affects more than 200,000 in the United States and for which there is no reasonable expectation that the cost of developing and making available in the United States a drug for such disease or condition will be recovered from sales in the United States of such drug." Statistically speaking, with a population of 287,400,000, that means roughly .07% of the US population.
The European Commission on Public Health defines rare diseases as "life-threatening or chronically debilitating diseases which are of such low prevalence that special combined efforts are needed to address them. As a guide, low prevalence is taken as prevalence of less than 5 per 10,000 in the Community." This would calculate into .05% of the overall population.
The National Cancer Institute held their 2nd Epidemiology Leadership Workshop in 2005. They discussed the issue of correctly identifying rare cancers, for statistical purposes. There thoughts on the situation were already known in the rare cancer community. They should have asked us first!
Our organization's primary purpose is to support those who have been diagnosed with a pediatric or rare adult cancer, for all geographic areas. We would rather err on the side of offering too much information. We have formulated several lists of cancers. If you do not see your pediatric or rare adult cancer listed on any of our cancers lists, please go to our Forums area.
The Rare Cancer Forum Members have cancers that are considered rare. A rare cancer list to validate this was compiled from several sources, including the Textbook of Uncommon Cancers, 3rd edition; the US Office of Rare Diseases (ORD); the National Organization for Rare Disorders (NORD); documents from Cancer BackUp, RareTumours.org, documents from eMedicine, tumor classifications and statistical data from SEER (Surveillance, Epidemiology, and End Results), and many oncology reference books, medical publications, and medical journals; both online and offline. This was a tedious task which resulted in these comprehensive lists of rare cancers. In some cases, we have included benign tumors that require cancer treatments or have the same physical effects.