The following three websites are authoritative and easy to use resources to help you select a cancer type as a paper topic.
National Cancer Institute, one of the agencies in the National Institutes of Health, was established in 1937 as the nation's primary center for cancer research and training. The home page lists common types of cancers followed by a comprehensive list by body location or system. There are also possibilities to search for cancers by age or sex. Each entry includes treatments, prevention, genetics, causes, clinical trials, statistics, additional literature, and research endeavors. There is also a separate section for clinical trials information. Statistics information under the tab, "Cancer Statistics" includes guides to understanding the figures as well as national and state data.
American Cancer Society, a professional association, has designed their website to be very user friendly to patients. However the content is substantive enough to help you with your paper. The "Learn about Cancer" tab includes search for a cancer by type or by selecting from a list. On the next screen, searchers are directed to a detailed guide which infludes definitions, causes, risk factors, prevention, detection, diagnosis, staging, and treatment. In the "Explore Research" section, you will discover Cancer Facts and Figures, state and national data collected by the ACS.
M D Anderson Manual of Medical Oncology, an e-book available through the database, Access Medicine, has been written by the staff at the M. D. Anderson Cancer Center at the University of Texas in Houston, one of the nation's top cancer medical centers. The Manual is written for physicians with references to the practices at M. D. Anderson. The book is organized by broad cancer types.