Skull base chordomas: clinical outcome in a consecutive series of 45 patients with long-term follow-up and evaluation of clinical and biological prognostic factors

Abstract

OBJECTIVE Skull base chordomas (SBCs) are rare dysembryogenetic invasive tumors with a variable tendency for recurrence. According to previous studies, the recurrence rate seems to be affected by both clinical variables and tumor biological features. The authors present the results of treatment of SBCs in a large series of patients and investigate the role of 1p36 chromosomal region loss of heterozygosity (LOH) as a prognostic factor. METHODS Between 1990 and 2011, 45 patients were treated for SBCs. The mean follow-up was 76 months (range 1-240 months). An LOH analysis was performed in 27 cases. Survival analysis was performed to determine clinical and biological parameters correlating with clinical outcome. RESULTS The 5- and 10-year overall survival rates were 67% and 57%, respectively. Five- and 10-year progression-free survival rates were 58% and 44%, respectively. Multivariate analysis showed that extent of resection, adjuvant radiation therapy, and absence of rhinopharynx invasion were positive independent predictors of overall survival. The latter 2 variables and a younger patient age were positive independent predictors of progression-free survival. Twenty-one patients showed 1p36 LOH. All events of recurrence and death clustered in the group of patients with 1p36 LOH; however, this biological marker was not statistically significant on multivariate analysis. CONCLUSIONS Resection is the treatment of choice in primary and recurrent SBC. Patient age, rhinopharynx invasion at diagnosis, extent of tumor removal, and postoperative radiation therapy influence SBC prognosis. Genetic analysis, even while showing interesting results, did not reveal 1p36 LOH as an independent predictor of clinical outcome.

Keywords: CCJ = craniocervical junction; GKRS = Gamma Knife radiosurgery; KPS = Karnofsky Performance Scale; LOH = loss of heterozygosity; OS = overall survival; PFS = progression-free survival; SBC = skull base chordoma; chordoma; clivus; loss of heterozygosity; radiation therapy; skull base surgery.