[Treatment modalities and prognostic factors of chordoma in the skull base]

To investigate the clinical characteristics, treatment modalities and prognostic factors of chordoma in the skull base.

The data of 37 patients with chordoma in the skull base treated from 1970 to 2002 were retrospectively reviewed. Twenty-eighty received surgery plus radiotherapy, 8 radiotherapy alone and 1 surgery alone. The total dose of irradiation ranged from 30 - 75 Gy with a median of 60 Gy.

The rates of symptom relief and remarkable tumor regression at the end of radiotherapy were 86.5% and 48.6%, respectively. The nerve and endocrine function recovery was observed in some patients within six months to two years after treatment. The overall 1-, 3-, 5- and 10-year survival were 97.3%, 87.3%, 71.5% and 41.0%, respectively. The overall 1-, 3-, 5- and 10-year survival were 100.0%, 92.9%, 85.7% and 50.8% in patients with palsies of cranial nerves II-VIII, but 100.0%, 75.0%, 45.0% and 0 in patients with dysfunction of cranial nerves IX-XII, respectively (P = 0.04).

Surgery is the first option for chordoma, but resection with a safe margin is difficult to achieve due to the special anatomical location of the skull base. Local failure is the main cause of death. Radiotherapy is an important adjuvant for local control. The total dose should not be less than 60 Gy for prophylactic purpose, and more than 70 Gy should be given to patients with recurrence, residual lesions after surgery or those not operated. The injury of cranial nerves IX-XII suggests a poor prognosis.