Gamma Knife Surgery For Skull Base Chordomas And Chondrosarcomas

Toshinori Hasegawa1, Yoshida Kida.2

1Komaki, Japan 2Komaki City Hospital, Komaki, Japan.

Keywords: chondrosarcoma, gamma knife, chordoma, skull base, outcome

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       Clinical outcomes for chordomas and chondrosarcomas are limited.
     To evaluate radiosurgical outcomes of skull base chordomas and chondrosarcomas, plus determine which tumors are appropriate for stereotactic radiosurgery as adjuvant therapy following maximum tumor resection.
     Thirty-seven patients (48 lesions) were treated using gamma knife surgery (GKS).
     The patients were treated using gamma knife surgery (GKS),including 27 chordomas, 7 chondrosarcomas and 3 radiologically diagnosed chordomas. Mean tumor volume was 20 cm3. Mean maximum and marginal doses were 28 and 14 Gy, respectively.
     Mean follow-up period was 97 and 59 months from diagnosis and GKS, respectively. The actuarial 5- and 10-year survival rate from GKS was 80% and 53%, respectively. The actuarial 5- and 10-year local tumor control (LTC) with single or multiple GKS sessions was 76% and 67%, respectively. A tumor volume of less than 20 cm3 significantly affected the high rate of LTC (p=0.0182). No patients had adverse radiation effects, other than one patient with worsened facial numbness despite successful tumor control.
     This is a retrospective study.
     GKS after surgical resection is a reasonable option as adjuvant treatment for selected patients harboring skull base chordomas or chondrosarcomas with a residual tumor volume of less than 20 cm3.
      Dose planning with a generous treatment volume to avoid marginal treatment failure should be made at a marginal dose of at least 15 Gy to achieve long-term tumor control.


Project Roles:

T. Hasegawa (), Y. Kida. ()