[Whole mediastinal irradiation with or without entire hemithoracic irradiation for invasive thymoma]

We retrospectively reviewed the case histories of 45 patients with invasive thymoma who underwent postoperative or definitive radiotherapy. Patients in stage II or stage III were classified according to the treatment volume as follows: a) those who received irradiation confined to the primary tumor site with a generous margin (involved field group, n = 17) and b)those who received prophylactic whole mediastinal irradiation with or without entire hemithoracic irradiation (prophylactic group, n = 21). Seven recurrences were observed among the involved field group, while all patients in the prophylactic group were relapse-free and alive after a median follow-up interval of 50 months. Major side effects were observed in two patients who received entire hemithoracic irradiation. One developed severe pneumonitis resulting in lung fibrosis that required hospitalization, while the other developed nephrotic syndrome of unknown cause. We conclude that whole mediastinal irradiation with or without entire hemithoracic irradiation can be used as a treatment of choice for postoperative invasive thymoma.