Areas of particular interest for Dr. Hallahan include lung cancer, lymphoma, and sarcoma (bone and soft tissue cancer). His professional affiliations include Barnes-Jewish West County Hospital, Washington University Physicians, and St. Louis Children's Hospital. He graduated from Rush Medical College and then he performed his residency at the University of Chicago Medical Center. Anthem, Blue Cross/Blue Shield, and Coventry are among the insurance carriers that Dr. Hallahan accepts. He is not currently accepting new patients.