He is double-boarded in hematology/oncology after completing a fellowship at the Mayo Clinic in Rochester, Minnesota, where he was chief fellow in that training program. He has a passionate interest in patient-doctor communication, including online dialogue, and moderates a Facebook group for patients with multiple endocrine neoplasia, a rare tumor syndrome that personally affects him and his son. He is also active on Twitter as @marklewismd. He is co-chair of the Social Media Working Group for SWOG, one of the nation’s largest cancer research cooperative groups, and co-chairs their Adolescent & Young Adult Cancer committee as well.