[Clinical outcome of epithelial tumors of the thymus]

We retrospectively reviewed treatment and clinical outcome of thymic epithelial tumors of 64 patients over a 20-year period. Clinical staging of the tumor was done by according to Masaoka classification. Histological diagnosis of the tumors was done by according to the second edition of the WHO histologic classification system for thymic epithelial tumors. Survival rate was calculated after Kaplan-Meire method.

Median age of patients was 53.7 years (ranged from 16 to 81). There were 30 men and 34 women. Eighteen patients had auto-immuno diseases. Sixty-two patients underwent surgery. In 57 patients resection was complete (extended thymo-thymectomy), but in the other five incomplete. The operative approach was median sternotomy in 51 patients and video-assisted thoracoscopic surgery in 6. Stage II to IV patients had postoperative mediastinal irradiation. Stage III to IV patients had postoperative cisplatin (CDDP) based chemotherapy. Inoperable patients were treated by chemo-radiotherapy. There were 42 stage I, 7 stage II, 11 stage III, 3 stage IV a, 1 stage IV b. The 5-year/10-year survival rates were 93%/89%, 71%/71%, 68.5%/--in patients with stage I, II and III. There were 5 type A tumors, 8 type AB tumors, 11 type B1 tumors, 11 type B2 tumors, 9 type B3 tumors, 11 type C tumors, the respect 5-year survival rates were 100%, 100%, 87.5%, 60%, 85.7% and 90%. Masaoka stage II to IV patients classified in B2, B3 and C type except one case.

Histologic type B2, B3 and C tumors may reflect the invasive nature. Masaoka staging system and the WHO histologic classification may help the assessment and treatment of patients with thymic epithelial tumor.