A proposal for treatment of invasive thymoma.

Eleven patients with invasive thymoma were treated with radiotherapy. All patients had gross anterior mediastinal tumors that invaded the adjacent structures, four of whom showed intrathoracic dissemination. Before radiotherapy, only one had macroscopic complete resection of the tumor, and another had partial resection; the other nine patients underwent biopsy only. All 11 patients achieved complete remission after radiotherapy, eight of whom have been free from relapse for 31 to 202 months. Three patients experienced recurrence within the thorax but outside the radiation fields. Even after whole mediastinal irradiation, recurrence could occur in the pleural cavity. Therefore, extended radiation fields including the entire hemithorax is recommended. Intensive combination chemotherapy was administered for two patients with recurrence and they achieved complete remission. A possible role of intensive chemotherapy in induction phase for invasive thymomas is discussed.