Cornelius A. Thiels, D.O., M.B.A., is a cancer surgeon at Mayo Clinic Comprehensive Cancer Center in Rochester, Minnesota, specializing in advanced and complex cancers, including pancreatic cancer, retroperitoneal and abdominal sarcomas, metastatic colorectal cancer, neuroendocrine tumors, and gastrointestinal stromal tumors. He provides comprehensive surgical care for patients with rare and aggressive cancers, using advanced and minimally invasive techniques including robotic surgery, intra-operative radiation therapy (IORT), and hyperthermic intraperitoneal chemotherapy (HIPEC) when appropriate. Dr. Thiels leads Mayo Clinic’s Hepatic Artery Infusion Pump Chemotherapy program and is Associate Chair of Innovation for the Department of Surgery.