A multivariate analysis of prognostic factors in thymoma.

BACKGROUND

Considering the prognostic factors of thymoma, the clinical stage is the most important, while controversies exist about other clinicopathologic factors. A multifactorial study was carried out to clarify the relationship between prognosis and sex, age, tumor size, presence of myasthenia gravis, staging, epithelial subtyping, lymphocyte/epithelial cell ratio (L/E ratio) and other adjuvant pathological features.

METHODS

One hundred and thirty-seven cases were collected in Veterans General Hospital-Taipei from 1961 to 1993. The aforementioned features were studied. Kaplan-Meier's actuarial survival analysis was adopted, with Logrank test, to determine the significance of overall heterogeneity and trend. Cox proportional hazard model was also used for multivariate analysis.

RESULTS

Among all tested prognostic factors, staging had the highest significance (relative risk = 3.00, p < 0.001) and age had only a moderate one (relative risk = 1.04, p = 0.011). No other clinicopathological factor showed any statistical significance for prognosis.

CONCLUSIONS

Staging remains of greatest usefulness in predicting the biological behavior of thymoma. The effect of age requires more investigation. Other clinicopathological features have no definite influence in survival expectancy.