Postoperative radiotherapy for stage I thymoma: a prospective randomized trial in 29 cases.
OBJECTIVE
To determine the effect of postoperative radiotherapy on stage I thymoma.


METHODS
Twenty-nine patients with stage I thymoma younger than 65 years, treated between August 1981 and January 1996 were included in this study. All patients were randomly assigned into two groups: surgery alone (13 patients) and surgery with postoperative radiotherapy (16). Staging was based on the surgical and pathologic criteria that the tumor had a complete capsule and without capsular invasion microscopically. Adjuvant radiotherapy was started within 4 weeks after surgery. Megavolage radiation, using the isocentric technique, was administered through an anterior field and/or two anterior oblique wedge fields. For the patients with lymphocytic predominant type, the dose was 50 Gy in 25 daily fractions for 5 weeks; for the patients with epithelial cell type or mixed type, the dose was 60 Gy in 30 daily fractions for 6 weeks. The survival rates were estimated by the Kaplan-Meier method.


RESULTS
There was no recurrence and metastasis in either group. No acute and late radiological injuries were found among the patients receiving radiotherapy postoperatively. The 5-year and 10-year survivals were both 92% for the patients treated by surgery alone. However, the survival rates for patients who received radiotherapy were both 88%. There was no difference in the survivals in these two groups. Of the 3 died patients, 1 died of myasthenia gravis and 2 of intercurrent illness. No significant correlation was found between myasthenia gravis and radiotherapy.


CONCLUSIONS
Postoperative radiotherapy is unnecessary for the patients with stage I thymoma. No relation is found between radiotherapy and myasthenia gravis.
Zhang
H
H
Department of Radiotherapy, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
Lu
N
N
Wang
M
M
Gu
X
X
Zhang
D
D
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant; D013945:Thymoma / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D013953:Thymus Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery