Original article: general thoracic
Therapy for thymic epithelial tumors: a clinical study of 1,320 patients from Japan

https://doi.org/10.1016/S0003-4975(03)00555-1Get rights and content

Abstract

Background

Surgery remains the mainstay of treatment for thymic epithelial tumors, and radiation and chemotherapy also have been applied widely as adjuvant and palliative procedures.

Methods

We compiled records of 1,320 patients with thymic epithelial tumors who were treated from 1990 to 1994 in 115 institutes certified as special institutes for general thoracic surgery by The Japanese Association for Chest Surgery.

Results

Patients with stage I thymoma were treated with only surgery, and patients with stage II and III thymoma and thymic carcinoid underwent surgery and additional radiotherapy. Patients with stage IV thymoma and thymic carcinoma were treated with radiation or chemotherapy. The Masaoka clinical stage is an excellent predictor of the prognosis of thymoma and thymic carcinoma, but not thymic carcinoid. In stage III and IV thymoma, the 5-year survival rates of total resection, subtotal resection, and inoperable groups were 93%, 64%, and 36%, respectively. On the other hand, in thymic carcinoma, the 5-year survival rates of total resection, subtotal resection, and inoperable groups were 67%, 30%, and 24%, respectively. Prophylactic mediastinal radiotherapy could not prevent local recurrences effectively in patients with totally resected stage II and III thymoma. Adjuvant therapy including radiation or chemotherapy did not improve the prognosis in patients with totally resected III and VI thymoma and thymic carcinoma.

Conclusions

Total resection is the most important factor in the treatment of thymic epithelial tumors. There is value in debulking surgery in invasive thymoma, but not in thymic carcinoma. We doubt that adjuvant therapy is valuable for patients with totally resected invasive thymoma and thymic carcinoma.

Section snippets

Patients

We sent a questionnaire on thymic epithelial tumors to 185 institutes certificated as special institutes by The Japanese Association for Chest Surgery, and received replies from 115 institutes (62%). We compiled records of 1,320 patients with thymic epithelial tumors (1,093 thymomas, 186 thymic carcinomas, and 41 thymic carcinoids) who were treated between 1990 and 1994. The thymoma patients consisted of 495 men and 590 women. The patients' ages ranged from 8 to 94 years, with a mean age of

Stage of disease

The stages and the histologic types of thymic epithelial tumors are shown as follows. In thymoma, 522 patients (48.3%) were in stage I, 247 (22.8%) in stage II, 204 (18.9%) in stage III, 73 (6.8%) in IVA, and 35 (3.2%) in IVB. In thymic carcinoma, 10 patients (5.3%) were in stage I, 11 (5.9%) in stage II, 74 (39.0%) in stage III, 26 (13.9%) in IVA, and 61 (32.6%) in IVB. In thymic carcinoid, 8 patients (19.5%) were in stage I, 4 (9.8%) in stage II, 12 (29.3%) in stage III, 4 (9.8%) in IVA, and

Comment

The Masaoka staging system is advocated as the appropriate one to adopt 7, 15. In this study, the rates of stage I, II, III, and IV thymoma were 48%, 23%, 19%, and 10%, respectively. The treatment of thymoma depends upon its clinical stage. Most patients with stage I thymoma were treated by surgery alone, and patients with stage II and III thymomas were treated by surgery with radiotherapy. Patients with stage IV thymomas were treated by surgery with adjuvant therapy including chemotherapy. Our

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