Skull Base Chordomas: Efficacy of Surgery Followed by Carbon Ion Radiotherapy

Background: Skull base chordomas are challenging to treat because of their invasive nature, critical location, and aggressive recurrence. We verified the effectiveness of combined radical skull base surgery with carbon ion radiotherapy for treating skull base chordomas.

Methods: Between November 1996 and August 2007, 32 patients (12 males and 20 females; mean age at initial presentation, 41.4 years; range, 10–75 years) with skull base chordomas underwent 59 operations. Subtotal resection (resection of > 90% of the preoperative tumor volume) was achieved in 24 out of 59 (40.7%) operations. After the surgical procedure, 9 of 32 (28.1%) patients underwent adjunctive carbon ion radiotherapy. The patients were followed up for a mean period of 36.3 months (range, 3–93 months) since their initial presentation.

Findings: Fifty percent of the patients had to be re-treated due to tumor regrowth during the follow-up period. Thus far, 3 patients have died of the tumor. The overall 7-year survival rate of the 9 patients who underwent carbon ion radiotherapy was 85.7%. The rate was higher compared with that of the surgical group alone (76.4%). The 3-year recurrence-free survival rates of the carbon ion therapy treated group was 70.0%, which was higher than that of other radiotherapy treated groups and the surgical group alone (57.1% and 7.1%, respectively). Log-rank analysis showed a significant difference in the recurrence-free survival rates between the group treated with adjunctive carbon ion radiotherapy and the group that was not treated with adjunctive radiotherapy (P = 0.001146).

Conclusions: Combined treatment—surgical removal of the tumor around the brainstem and the optic nerve plus postoperative carbon ion radiotherapy to the skull base structures—will improve the survival rate and quality of life of patients with complicated skull base chordomas.