Panel A shows the relative risk of cancer among patients who had undergone thymectomy as compared with age-, race-, and sex-matched controls in the first 5 years after surgery, both in the overall study population and in subgroups. The relative risk of cancer within 5 years was increased in patients who had undergone thymectomy, regardless of whether they had a preoperative history of infection, cancer, or autoimmune disease. Panels B and C show the percentages of patients who survived without cancer over a period of 20 years after surgery in the group with no exclusions (Panel B) and in the subgroup in which patients with a preoperative history of infection, cancer, or autoimmune disease were excluded from the analysis. The insets show the same data on an expanded y axis.