Dr. Mammen is the Merle M. Musselman Professor at the University of Nebraska and the Physician-in-Chief of the Fred and Pamela Buffett Cancer Center. He is also serves as the Chief of Surgical Oncology and Vice-Chair for Academic Affairs in the Department of Surgery at the University of Nebraska.

Dr. Mammen’s clinical practice focuses on patients with advanced cutaneous malignancies (including melanoma and Merkel cell cancer) and soft tissue sarcomas. Dr. Mammen’s clinical and translational research focuses on melanoma, soft tissue sarcomas, breast cancer, and pancreatic cancer. He is an experienced clinical trialist and serves as the national primary investigator of a melanoma clinical trial (SWOG 2015) and the national co-primary investigator of a breast cancer clinical trial that recently completed enrollment (SWOG 1418).  Dr. Mammen also has a translational research effort and serves as the PI of NCI R01CA295693 entitled Porcine Platforms For Technology Development In Pancreatic Cancer.

Dr. Mammen has served in leadership positions in numerous surgical organizations. He is currently the Chair of the American College of Surgeons Political Action Committee (SurgeonsPAC). He recently completed his term on the American Board of Surgery where he was Councilor, Chair of the Education and Training Committee, and Chair of the Complex General Surgical Oncology Continuous Certification Assessment Committee. Dr. Mammen has served in the past as the President of the Kansas Chapter of the American College of Surgeons, the Kansas City Medical Association, and the Kansas City Surgical Society. He was the Chair of both the Resident and Associate Society of the American College of Surgeons and the Young Fellows Association of the American College of Surgeons.