Recurrent Skull Base Chordomas: Role of Surgery

Abstract

Skull base chordomas have a notorious tendency to recur even after wide radical removal of the soft tissue and osseous tumor and extensive drilling removal of surrounding bone. Their high recurrence rates warrant adjuvant high-dose radiation therapy. This combination of radical removal and high-dose radiotherapy delays the time of recurrence, but in most cases, the tumor eventually recurs locally. These recurrent cases present quite a challenge, particularly in the reconstruction intended to prevent CSF leak. Scar and radiation-induced angiopathy challenge tumor dissection and increase the risk of vascular injury, and tissue devitalized by prior surgery and radiation is less useful for closure and prevention of CSF fistulas. These considerations favor an approach for reoperation that differs from the original. Multiple and staged reoperations require thorough planning that considers potential extent of resection, possible complications, particularly poor wound healing and CSF leak, reconstruction, including donor sites of autologous tissue, and the patient’s health and likely recovery time. As a rule, the surgical treatment of recurrent chordomas should aim to achieve complete tumor removal. This requires the mastery and use of multiple skull base approaches and facility with all tools of the skull base surgical armamentarium, including intraoperative imaging and/or navigation.

Keywords

Chordoma, Clivus, Recurrent skull base tumors, Surgical approaches, Tumor excision

Outline
Introduction 393
Diagnosis of Recurrent Tumor 393
Decision-Making 395
Morbidity and Mortality of Reoperation 397
Conclusions 398
References 398

Introduction

Chordomas are unusual malignant dysontogenic neoplasms with a low incidence (less than 0.03 per 100,0000 person) and unpredictable growth rate. Chordomas are invasive and locally destructive. Their pathological diagnosis can only be confirmed by immunohistochemical stains. Midline origin from rather thin bone and bilateral extension through the base of the skull usually precludes en bloc oncological removal of clival chordomas. Even so, the role of radical resection is well established and is often undertaken. Even after wide radical removal of the soft tissue and osseous tumor and extensive drilling removal of surrounding bone skull base, chordomas have a notorious tendency to recur. Their high recurrence rates after surgery alone warrant adjuvant high-dose radiation therapy. This combination of radical removal and high-dose radiotherapy delays the time of recurrence, but in most cases, the tumor eventually recurs locally. These recurrent cases present quite a challenge, particularly in the reconstruction intended to prevent CSF leak. Scar and radiation-induced angiopathy challenge tumor dissection and increase the risk of vascular injury, and tissue devitalized by prior surgery and radiation is less useful for closure and prevention of CSF fistulas. These considerations favor an approach for reoperation that differs from the original. In this chapter we address the role of reoperation in the management of recurrent skull base chordomas ( Figs. 37.1–37.4 ).

Diagnosis of Recurrent Tumor

Chordoma recurrence presents clinically and radiographically. Postoperative follow-up must be regular and unlimited in duration. The extent of resection should be evaluated by CT and MR imaging within 48 h of the initial operation and then 3 and 6 months later. Immediate postoperative scanning is mandatory to assess the extent of surgical removal, to guide postoperative radiotherapy, and to provide a baseline for comparison with subsequent studies. Tumor recurrence, radiation tissue injury, infection, and craniospinal instability can cause new signs and symptoms. The surgical route should be carefully scrutinized for seeding of tumor. New symptoms without radiologic evidence of tumor presence are warning signs that should be closely followed. Despite the high resolution of MRI, recurrent tumor can be misinterpreted as surgical scar or radiation effects. CT is often valuable in revealing new invasion and erosion of the surrounding bone ( Figs. 37.5–37.7 ).