Author(s): Zhang H, Lu N, Wang M, Gu X, Zhang D
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Abstract 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.
This article was published in Chin Med J (Engl)
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