[Treatment of primary mediastinal germ cell tumors]

Primary mediastinal germ cell tumors are clinically classified into mature (benign) teratomas and malignant germ cell tumors. Mature teratomas should be surgically excised after diagnosis, because unnecessary delay may result in the rupture of tumors or in malignant degeneration. The prognosis after surgical removal of tumor is good and there is no recurrence of tumor after complete excision. Malignant germ cell tumors are therapeutically classified into seminomatous and nonseminomatous germ cell tumors. Nonseminomatous germ cell tumors comprise immature teratoma, teratocarcinoma (malignant teratoma), embryonal carcinoma, yolk sac (endodermal sinus) tumor and choriocarcinoma. Treatments for patients with them require an multidisciplinary therapeutic approach with radiotherapy or chemotherapy combined with surgical intervention. The prognosis of patients with these tumors are poor, however seminomatous germ cell tumors have a better prognosis than that of nonseminomatous tumors, because they are responsive to radiotherapy or chemotherapy and long survivals over five years after treatment are not rare among them. An aggressive cisplatin-based combination chemotherapy is performed for patients with nonseminomatous tumors who have mostly the elevated serum levels of AFP or beta-HCG as tumor marker. The serum levels of tumor markers reflect precisely the biological behavior of nonseminomatous tumors. Patients with the normalised serum levels of tumor markers after an medical intervention may have a good long prognosis following radical resection of tumors, although the sustained high serum levels of tumor markers after treatment indicate a poor prognosis. Long survivals over five years after therapy are extremely rare among them.