With more than 85 hospitals within the metropolitan area, Houston is a world leader in medicine and boasts the world's largest medical complex. Approximately 5.2 million patients—more than 10,000 of them foreign—are treated each year in the Texas Medical Center alone, a centralized facility begun in 1943. The facility's 42 nonprofit and government institutions include 13 hospitals and two specialized patient facilities. It comprises Texas Children's Hospital, Methodist Hospital, and St. Luke's Episcopal Hospital, as well as the M.D. Anderson Cancer Center, which was ranked as the best hospital for cancer treatment by U.S. News & World Report in 2004, along with top 10 rankings in the fields of gynecology, urology, and ear, nose, and throat. Houston's medical community is known for its major contributions in the areas of cardiac care, cancer research and therapy, trauma care, and innovative medical treatment. Some of Houston's other major hospitals include the Menninger Clinic and TIRR: The Institute for Rehabilitation & Research.