Introduction
Cancer is the second-leading cause of death in the United States; approximately 23% of all US deaths are due to cancer. In 2015, 1.6 million new cases were diagnosed in the United States, and 595,919 deaths occurred. In 2016, more than 15.5 million Americans had a history of cancer; it is estimated that cancer will develop in approximately 38% of US men and women during their lifetimes. Worldwide, in 2012, there were 14 million new cases and 8.2 million deaths due to cancer. Developing countries are disproportionately affected, accounting for 60% of all new cases and 70% of all deaths due to cancer.
Cancer is the term used to refer to a group of related diseases; discussions of etiology, prevention, and cure must therefore address the specific types of tumors. Nonmelanotic skin cancers, including squamous cell and basal cell carcinomas, are the most common tumors, but these cancers are rarely a cause of death. After skin cancer, the most common forms of cancer in adult Americans (in decreasing order of incidence) are breast, lung, prostate, and colorectal. Approximately 80% of adult cancers arise from the epithelial tissues.
Cancer is the second-leading cause of death in children younger than 15 years in the United States, trailing only accidental death. Nevertheless, death rates have dropped, and survival rates have risen sharply. The 5-year survival rate for all childhood cancers combined has improved in the United States, from approximately 51% in 1973 to over 80% today.
Excerpted from BCSC 2020-2021 series: Section 1 - Update on General Medicine. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.