21st Century Oncology Holdings, Inc. is a physician-led provider of integrated cancer care services headquartered in Fort Myers, Florida. Founded in 1983, the company operates a network of 179 cancer treatment centers across 17 U.S. states and seven Latin American countries. It employs 3,631 workers, including 350 physicians, providing radiation therapy, surgical oncology, and support services. The company utilizes both direct-employment and management-services models to navigate varied regulatory landscapes for oncology care.