The Treatment of Chordoma and Chondrosarcoma of the Skull Base with Particular Attention to Radiotherapy

Chordoma and Chondrosarcoma are rare, locally aggressive, tumors occurring in one third of cases in the base of the skull. Although the risk of distant metastasis is low, without adequate therapy, these tumors often recur locally with significant morbidity and mortality. The mainstay of treatment is maximal tumor debunking. A gross total resection, however, is difficult to achieve, often leaving residual tumor. Adjuvant radiation is considered a standard therapeutic option postoperatively to reduce the risk of local recurrence and increase survival. High doses of radiation are required, as these tumors are considered relatively radioresistant but the presence of several organs at risks a major challenge with respect to covering the target with the prescribed high dose. In this regards, protons, for their physical and dosimetric advantages, have become a standard of care. Even though some reports have shown clinical activity with the use of chemotherapy or biologic drugs, there is no role at the moment for medical treatment. Maurizio Amichetti*, Dante Amelio, Marco Cianchetti, Irene Giacomelli and Daniele Scartoni Department of Oncology, Azienda Provinciale per i Servizi Sanitari, Italy Maurizio Amichetti, et al., Clinics in Oncology Lung Cancer Remedy Publications LLC. , | http://clinicsinoncology.com/ 2017 | Volume 2 | Article 1195 2 on a case-by-case basis. Transphenoidal, transanal, trans maxillary, anterior cervical retro pharyngeal, and transanal approaches have been well documented [6]. Surgical results and clinical outcomes have improved throughout the years [7]. A variety of both open and endoscopic therapeutic approaches have evolved, with an emphasis on neurological preservation, increasing the rate of gross total resection and reducing morbidity. To exploit a total resection can be challenging because of difficult access, anatomic constraints, infiltrative nature of the lesion, and proximity to critical structures such as optic nerves, optic chiasm, cranial nerves, cochlea, brainstem, pituitary gland, and temporal lobes. Lateral extension of the disease often can be accessed with endoscopic nasal approaches [8]. The most challenging side effect with endoscopic approaches is the defect closure and prevention of Cerebrospinal Fluid (CSF) leak. With the increased experience with endoscopic skull-based techniques, improved instrumentation, and, if needed, the use of arterially based mucosal flaps for cerebrospinal fluid leak closure, the ability to approach resections of these lesions has significantly improved [9-12] permitting more thorough removal of tumor with less postoperative morbidity. Local Recurrence (LR) with surgery alone has been found very high (>50%) mainly in Chand can be associated with significant morbidity [13]. Chondrosarcoma appear to be more indolent than chordomas, which may lead to favoring a more conservative initial surgery. Some small tumors and other select cases may be addressed with observation alone if of low-grade. In these cases, residual tumor can be observed closely without adjuvant treatment; being local recurrence rates and ability to metastasize less than Chordoma. Considering the high rate of LR, postoperative radiotherapy plays a very important role in a global therapeutic approach; however, there is currently no clear consensus on the post-surgical radiation treatments that should be used after maximal resection. Patients sometimes can subsequently develop recurrent disease along the cervical skin incision due to surgical seeding: tumor seeding can occur anywhere along the operative route and is often outside the field of radiotherapy [14] even though the frequency of this occurrence is reported in less than 5% of cases and the need to include it in the radiotherapy field is controversial [15]. The use of novel clean oncologic techniques to minimize exposure may help limit tumor seeding.