Background: This study was designed to analyze the accuracy and reliability of several prognostic indicators for long-term survival of thymoma patients.
Methods: Data from 142 patients treated for thymoma at the Tianjin Medical University Cancer Hospital from January 1954 to January 2001 were retrospectively analyzed. The Kaplan-Meier method and Cox's proportional hazards model test were used for single and multi-variable analyses respectively. The Log-rank test was used to compare survival between groups.
Results: The sizes and extent of the tumors were classified as I - IV according to the Masaoka clinical staging scale. Respective 5- and 10-year survival rates were: 93.8% and 79.2% in stage I, 79.3% and 55.2% in stage II, 53.1% and 34.4% in stage III, and no survivors in stage IV. Among 30 patients with associated myasthenia gravis, 19 had generalized myasthenia gravis and 11 had ocular myasthenia gravis; 5- and 10-year survival rates were 83.3% and 60.0%, respectively. The 5- and 10-year survival rates for 112 patients without myasthenia gravis were 53.6% and 42.0%, respectively. Eighty-four patients had radical resection and nine had palliative resection. Eighty-nine patients had radiotherapy and 55 patients had postoperative radiotherapy. Single or multi-variable analyses showed that the main prognostic indicators are Masaoka clinical staging, thymoma-associated myasthenia gravis, and the treatment method.
Conclusions: The most important indicators of long-term survival in thymoma are Masaoka clinical staging and the completeness of resection. The primary treatment method for thymoma should be wide tumor resection. Pre- and/or postoperative radio- and/or chemotherapy should be given according to individual treatment requirements.