Conventional external radiotherapy in the management of clivus chordomas with overt residual disease

Cranial chordomas are uncommon tumors accounting for less than 1% of all intracranial neoplasms. Although they are slowly growing, rarely metastasizing tumors, cranial chordomas are challenging to treat due to their critical location, invasive nature and aggressive recurrence. The aim of this retrospective study was to evaluate the role of conventional irradiation in the treatment of clival chordomas with overt residual disease after incomplete surgery. Between January 1979 and December 1997, 18 patients with histologically confirmed clival chordoma were treated with radiotherapy. Median age at the time of diagnosis was 32 years. The mean duration of the symptoms before diagnosis was 33.9 months. Median tumor diameter at initial presentation was 5 cm (range, 3-7 cm). The type of surgical procedure was subtotal excision in 11 patients and biopsy in 7. Radiation treatment was delivered with megavoltage units, and total doses between 50 Gy and 64 Gy (median, 60 Gy) were administered with conventional daily fractions. One patient received additional 12.50 Gy with linear accelerator-based stereotactic radiosurgery after subtotal excision and external irradiation. The mean follow-up time was 43.2 months. Overall survival at 5 years was 35%. Eleven patients showed progression after radiotherapy. The median time to progression after radiotherapy was 40.8 months (38.4-43.2) with a 5-year progression-free survival of 23%. Five patients (29.4%) showed symptomatic relief after radiotherapy while persistent symptoms were recorded for 6 patients. Incomplete surgery and conventional external radiotherapy with a dose of around 60 Gy seem to be inadequate in the treatment of clival chordomas.