Midterm prognosis and surgical implication for clival chordomas after extended transsphenoidal tumor removal and gamma knife radiosurgery

BACKGROUND: Treating chordoma through surgery alone is often ineffective. Thus, surgery often performed with irradiation, with a reported 5-year survival rate of 60–75%. The clinical course varies, and disease rarity prevents larger number of clinical investigations. METHODS: In total, 19 patients with clival chordomas were retrospectively extracted from our institutional database. They were initially treated with maximal tumor removal using the extended transsphenoidal approach between March 2006 and January 2021. When total tumor removal was achieved, prophylactic irradiation was not performed. If tumor remnants or recurrence were confirmed, Gamma Knife (GK) radiosurgery was performed. The mean follow-up period was 106.7 months (ranged 27–224 months). The clinical course and prognostic factors were investigated. RESULTS: Total removal was achieved in 10 patients, whereas 4 patients suffered recurrence and required GK. GK was applied to 11 patients with a 50% isodose of 13–18 Gy (mean: 15.4 Gy), and eight patients remained progression free, whereas three patients suffered repeated local recurrence and died of tumor-related complications. The mean overall progression-free interval was 57.2 months (range: 6–169 months). One male patient died of tumor un-related lung cancer 36 months after the initial treatment, and other patients survived throughout the observational periods. The mean overall survival was 106.7 months (range: 27–224 months). Thus, the 5-year survival rate was 94.7%. Statistical analysis indicated that sex (men), > 15 Gy of 50% isodose by GK, and screening brain examinations as prophylactic medicine were significant favorable prognostic factors. CONCLUSIONS: The favorable outcomes in this investigation suggest the importance of early detection and treatment. Surgery may enable better conditions for sufficient GK doses.