Primary mediastinal malignancies: findings in 219 patients

The purpose of this study was to determine the demographics, histology, methods of treatment, and survival in primary mediastinal malignancies. We did a retrospective review of the statewide New Mexico Tumor Registry for all malignant tumors treated between January 1, 1973 and December 31, 1995. Benign tumors and cysts of the mediastinum were excluded. Two hundred nineteen patients were identified from a total of 110,284 patients with primary malignancies: 55% of tumors were lymphomas, 16% malignant germ cell tumors, 14% malignant thymomas, 5% sarcomas, 3% malignant neurogenic tumors, and 7% other tumors. There were significant differences in gender between histologies (P < 0.001). Ninety-four percent of germ cell tumors occurred in males, 66% of neurogenic tumors were in females; other tumors occurred in males in 58% of cases. There were also significant differences in ages by histology (P < 0.001). Neurogenic tumors were most common in the first decade, lymphomas and germ cell tumors in the second to fourth decades, and lymphomas and thymomas in patients in their fifth decades and beyond. Stage at presentation (P = 0.001) and treatment (P < 0.001) also differed significantly between histologic groups. Five-year survival was 54% for lymphomas, 51% for malignant germ cell tumors, 49% for malignant thymomas, 33% for sarcomas, 56% for neurogenic tumors, and 51% overall. These survival rates were not statistically different (P > 0.50). Lymphomas, malignant germ cell tumors, and thymomas were the most frequently encountered malignant primary mediastinal neoplasms in this contemporary series of patients. Demographics, stage at presentation, and treatment modality varied significantly by histology. Despite these differences, overall five-year survival was not statistically different.