The role of radiation therapy in the management of ependymomas of the spinal cord.

Twenty patients with biopsy-proven ependymomas of the spinal cord were treated between 1960 and 1984-7 with surgery only, 3 with radiation therapy only, and 10 with surgery and postoperative radiation therapy. Of these, 2 patients developed recurrent tumor at the primary site, 3 developed a recurrent tumor in the thecal sac, and 1 developed distant metastasis. The absolute 5- and 10-year survival rates were 95% (19/20) and 86% (12/14), respectively. None of 13 patients who were treated with radiation therapy only or combined surgery and postoperative radiation therapy developed recurrent tumor at the primary site, and none of 7 patients who received thecal sac irradiation developed thecal sac recurrences. In contrast, 2 of 7 patients (29%) treated with surgery alone developed recurrent tumor at the primary site, and 3 of 13 patients (23%) who received no thecal sac irradiation developed a recurrent tumor in the thecal sac. The failure rates following surgery were greatest in patients who had tumor removed in a piecemeal fashion (43%, 6/14). The results show that radiation therapy is probably not necessary if the tumor has been removed completely in an en bloc fashion. However, radiation therapy is needed if the tumor has been incompletely removed or removed in a piecemeal fashion. If the tumor has been removed in a piecemeal fashion, the radiation portals should be extended to include the thecal sac. Histologic subtypes influenced the pattern of recurrence. Myxopapillary ependymomas and high grade cellular ependymomas appear to be more likely to recur in the thecal sac. However, no big difference could be detected in local recurrence.