Skull base chordoma

Abstract

Chordomas are malignant primary bone neoplasms. Although chordomas are generally slow growing neoplasms, they present complex management challenges. Surgical cure is uncommon because of local invasion. The primary goal of treatment is to prevent tumor progression that might compromise survival and quality of life. Almost all chordomas are best treated by a combination of radical surgical resection and high-dose radiotherapy. High doses of radiation are required for long-term local control of chordomas, which were once thought to be radioresistant. Adding high-dose radiation treatment to surgery improved the local control rate. However, the morbidity caused by tissue injury as a result of radiation treatment increases with escalating radiation dose. The Bragg peak effect of charged particles allows delivery of high doses to a treatment volume with limited effect on the surrounding tissue. The cost and subsequent limited availability of proton beam therapy prompted a search for other safe ways to deliver high dose radiation. New radiation delivery techniques, such as the CyberKnife (CK), have achieved dose distributions and patient outcomes similar to those of proton beam radiotherapy. Our current approach is to target residual chordoma and surrounding areas at risk of recurrence with as high a dose (up to 80 Gy equivalent) as permitted by the radiation tolerance of surrounding neural structures. CK stereotactic radiosurgery is a safe, effective treatment for primary or recurrent clival chordomas.