[Long-term results of the surgical treatment for thymoma]

Long-term results of the surgical treatment for 27 cases of thymoma were studied. The clinical stages according to Masaoka's classification were: 7 cases of stage I, 9 cases of stage II, 8 cases of stage III, 1 case of stage IVa and 2 cases of stage IVb. The histological classifications were: epithelial cell type in 10 cases, lymphocytic type in 9 cases and mixed type in 8 cases. Complications consisted of 18 cases of myasthenia gravis (MG). The long-term survival at 5 and 10 years were as follows: 90.6%, 74.8% in all cases; 100.0%, 50.0% in the non-invasive type; 88.2%, 80.2% in the invasive type; 72.0%, 72.0% in the epithelial cell type; 100.0%, 75.0% in the lymphocytic type; 100.0%, 80.0% in the mixed type; 88.9%, 44.4% in cases not complicated with MG; 92.9%, 84.4% in cases complicated with MG. Complete resection and adjuvant therapy improved prognosis even in cases of invasive thymoma, but one case died due to local recurrence of thymoma at 10 years after operation, so we emphasize it is important to follow up for the long time period more than 10 years.