[DNA content analysis and prognostic evaluation of thymoma]

To assess the prognostic value of DNA content, we performed flow cytometric studies using paraffin-embedded archiaval material from 52 patients who underwent surgical resection due to thymoma from 1961 to 1989. The results showed clinical stage and DNA content were prognostic factors independent of each other (P = 0.034 and P = 0.026). The 5- and 10-year survival rates of the patients with diploid (100% and 98%) were better than those of aneuploid (85% and 44%) (P < 0.01). The aneuploid patients with DI (DNA Index) < 1.2 had more favorable 5-year survival rate (100%) than those with DI > 1.2 (74.1%) (P < 0.01). Pathohistological type, myasthenia gravis and PI were not related to prognosis (P > 0.05). The DNA content and PI of the three recurrent thymomas which were all aneuploid had no statistical variation between two operations (P > 0.05).