Incidence, treatment, and survival analysis in mediastinal malignant teratoma population

BACKGROUND: Mediastinal malignant teratoma, as a germ cell tumor, is rare and lacking of population-based study. This study aims to illustrate the incidence, treatment and prognosis of mediastinal malignant teratoma by using a population-based database. METHODS: We gathered clinicopathological data (1975–2016) of malignant teratoma from the Surveillance, Epidemiology and End Results (SEER) database. Then we conducted analysis on the incidence, treatment and prognosis of mediastinal malignant teratoma and other malignant teratomas. RESULTS: A total of 5,550 cases were in our study cohort, including mediastinal malignant teratoma (n=133) and other malignant teratomas (n=5,417). The incidence of mediastinal malignant teratoma in 2016 was 0.004 per 100,000 persons. Both overall survival (OS) and cancer-specific survival (CSS) of mediastinal malignant teratoma were significantly worse than those of other malignant teratomas (both P<0.001). Surgery significantly improved OS and CSS of either early-staged or all-staged patients with mediastinal malignant teratoma (all P<0.001). However, both chemotherapy and radiotherapy negatively influenced both OS and CSS of patients with mediastinal malignant teratomas (all P<0.001). Besides, compared with surgery alone, combinational therapies like surgery + chemotherapy or surgery + radiotherapy were more harmful to OS and CSS (all P<0.001) of patients with mediastinal malignant teratoma. CONCLUSIONS: Our population-based evidence showed that mediastinal malignant teratoma, a rare cancer, had worse prognosis compared with other malignant teratomas. Compared with chemotherapy and radiotherapy, surgery could yield more survival benefits for either early-staged or all-staged patients with mediastinal malignant teratoma. Adjuvant use of chemotherapy/radiotherapy to surgery cannot improve but potentially harm patient prognosis.