THYMOMA - A MULTIVARIATE-ANALYSIS OF FACTORS PREDICTING SURVIVAL

Background. Despite complete surgical excision, malignant thymomas oft en recur with resultant death. We reviewed our series to determine whi ch factors independently predict survival after surgical resection. Me thods. A retrospective analysis of patients operated on for thymoma be tween 1949 and 1993 at Memorial Sloan-Kettering Cancer Center was perf ormed. Clinical data were collected from chart review. Only patients w ith a pathology report confirming the diagnosis of thymoma were includ ed in this analysis. Kaplan-Meier survival curves were generated and c omparisons of survival analyzed by log rank test. Multivariate analysi s was performed by the Cox proportional hazards model. Results. One hu ndred eighteen patients with thymoma underwent operation. There were 8 6 complete resections (73%), 18 partial resections (15%), and 14 biops ies (12%). By Masaoka staging, 25 patients were stage I (21%), 41 stag e II (35%), 43 stage III (36%), and 9 stage IVa (8%). Overall survival was 77% at 5 years and 55% at 10 years. Tumor recurred in 25 (29%) of 86 completely resected thymomas. Stage of disease (p = 0.03) was the only independent prognostic factor affecting recurrence. By multivaria te analysis, stage (p = 0.003), tumor size (p = 0.0001), histology (p = 0.004), and extent of surgical resection (p = 0.0006) were independe nt predictors of long-term survival. Conclusions. Patients with stage I disease require no further therapy after complete surgical resection . Neoadjuvant therapy should be considered for patients with large tum ors and invasive disease.