Skull base chordomas: efficacy of surgery followed by carbon ion radiotherapy

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

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. Sub-total resection (resection of >90% of the pre-operative tumour volume) was achieved in 24 out of 59 (40.7%) operations. After surgical excision, 9/32 (28.1%) patients underwent adjuvant carbon ion radiotherapy. The patients were followed up for a mean period of 36.3 months (range, 3-93 months) from the initial presentation.

Fifty percent of the patients had to be re-treated due to tumour regrowth during the follow-up period. Thus far, 3 patients have died from the neoplasms. The overall 7 year survival rate of 9 patients who underwent carbon ion radiotherapy was 85.7%. The rate was higher compared to that of others (76.4%). The 3 year recurrence free survival rates of carbon ion therapy treated group was 70.0%, being higher than that of the other groups treated with radiotherapy or untreated (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 untreated group (P = 0.001146).

Surgical removal of the tumour around the brainstem and the optic nerve combined with post-operative carbon ion radiotherapy will improve the survival rate and quality of life of patients with complicated skull base chordomas.