ABSTRACT
BACKGROUND: Radiotherapy has a well recognized role as an adjuvant treatment to surgery in thymoma and remains the only available treatment, with or without chemotherapy, in unresectable tumors. OBJECTIVE: Our objective is to assess the factors predicting the outcome and the pattern of survival in patients with thymoma treated by radiotherapy in our institution. METHODS: Between February 1989 and October 2000, 27 patients underwent radiotherapy for thymoma and were reviewed retrospectively. A follow-up could be obtained on all 27 patients. The parameters assessed were: age, sex, stage, presenting Myasthenia gravis, resectability, treatment modalities and survival. The total radiation dose to the tumor area in the adjuvant setting was 40-60 Gy and in the curative setting: 50-70 Gy. RESULTS: The median follow-up time of the 18 living patients was 74 months (range: 8-144 months). According to the Masaoka classification, there were 8 stage IV, 14 stage III and 5 stage II patients (three patients had relapsed tumors). There were 15 males and 12 females with a median age of 56 years. Ten patients had Myasthenia gravis at the time of presentation, two patients had pure red cell aplasia. Eighteen patients had dyspnea or superior vena caval syndrome (six of them). And five patients had only mild chest discomfort. Sixteen patients had complete surgical resection and 11 patients had partial resection (5) or only biopsy (6). Ten of them received a mean of three courses of chemotherapy with Cisplatin, Doxorubicin, and Cyclophosphamide (CAP). The overall 5 and 10 years survival rates were 65 and 47%, respectively. The 5 years survival rate for patients with complete resection was 81% compared to 44% for patients with partial resection or biopsy (P=0.01). Patients with Myasthenia had a 5 years survival of 71% compared to 53% for non-myasthenic patients. All patients with Myasthenia had complete surgical resection. Age, sex, presence of anemia, or superior vena caval syndrome were not adverse prognostic factors. There was no difference in terms of survival between relapsed and newly diagnosed tumors or between debulking surgery and biopsy. The 2 years survival for the four patients non-responders to chemotherapy was 0% while the 5 years survival for the responders was 71% (P=0.005). CONCLUSION: Resectability and response to chemotherapy for unresectable patients seem to be factors that predict the outcome in thymoma. Myasthenia gravis appears to be important in detecting the tumor when it is still resectable.
