Impact of thymectomy on all-cause mortality and risk of cancer in adults

The function of the thymus in human adults is unclear, and routine removal of the thymus is performed in a variety of surgical procedures. A case-control study at Massachusetts General Hospital (Boston) compared patients who had undergone thymectomy versus demographically matched controls who had undergone similar cardiothoracic surgery without thymectomy. At five years after surgery, all-cause mortality was higher in the thymectomy group than in the control group (8.1% versus 2.8%; relative risk 2.9; 95% CI 1.3-3.2), as was the risk of cancer (7.4% versus 3.7%; relative risk 2.0; 95% CI 1.3-3.2). Risk of autoimmune disease did not differ significantly between the groups, but a difference was found when patients with preoperative infection, cancer, or autoimmune disease were excluded from the analysis.