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Griff Harsh, editor. Thieme: New York. 2003 384 pp. $179 0-86577-985-6.
In Chordomas and Chondrosarcomas of the Skull Base and Spine, Griff Harsh has accomplished the major task of assembling a renowned group of surgeons, pathologists, radiologists, and radiotherapists who have contributed their specialized knowledge gained through hard-earned experience with these uncommon but intriguing tumors of the skull base and spine.
Chordomas and chondrosarcomas are rare tumors that arise from notochordal remnants and from primitive mesenchymal cells, respectively. They involve the skull base, sacrum, and (less frequently) the remaining vertebral column. Because of their critical location, local aggressiveness, and high recurrence rate, these tumors often demonstrate a malignant course, and their management requires a multidisciplinary approach. They are considered together in this review because of their similarities in radiologic and histologic appearance, and their similar biology and prescribed treatments. Harsh’s volume is the first to address in a comprehensive manner the embryology, pathology, imaging, presentation, and diagnosis of chordomas and chondrosarcomas, as well as the various surgical and radiation therapy options for patients with these tumors. The authors and contributing advisers are all experts in their fields and have significantly contributed to the literature prior to this publication.
The book is well organized into seven separate parts. Part I, Embryology and Pathology, includes a discussion of the role of the notochord in embryogenesis and the various histologic variants of chordomas (chondroid, conventional, and dedifferentiated) and chondrosarcomas.
In Part II, the differential diagnosis chapter demonstrates the breadth of possible disease entities occurring in the base of the skull that typically negate a biopsy to rule out pathologies that are best treated by nonsurgical modalities (e.g., nasopharyngeal carcinoma, lymphoma). Once a diagnosis of a skull base chordoma or chondrosarcoma is established, a preoperative plan needs to address what can and cannot be safely removed by surgery and to determine the desired approach. In that respect, the chapter in Part III by Rhoton and Seone, “Surgical anatomy of the skull base,” with its superb illustrations, will serve as a reference. Parts III, IV, and V present a variety of well-described surgical approaches, categorized as anterior (subfrontal, transfacial) and lateral (anterior and posterior petrosectomies) approaches. Anterior approaches are best for midline extradural tumors and are limited by the carotid arteries and jugular foramens. In contrast, lateral approaches are best for eccentric tumors with significant intradural extension. The authors’ recommended “best” approach is frequently dependent on the experience and versatility of the surgical team. In all cases, the authors recommend a maximal safe resection followed by radiation therapy.
The most promising form of irradiation, according to the authors in Part VI, appears to be fractionated proton beam radiotherapy, which has shown local recurrence-free survival of 73% and 98% of chordomas and chondrosarcomas at 5 years and 54% and 94% at 10 years, respectively. However, none of the studies described in this book are randomized, and therefore other forms of radiotherapy—such as stereotactic radiosurgery, stereotactic fractionated radiotherapy, and 3-D modulated conformal X-ray therapy—are also rational choices.
The authors opine that for spinal chordomas and chondrosarcomas an en bloc resection with negative margins offers the best disease-free survival and chance for a cure. For practical purposes, this can be achieved primarily in sacral tumors by posterior, anterior, or combined approaches. The authors also recommend and describe a total spondylectomy for tumors of the mobile spine. In the majority of cases, an anterior and posterior spinal reconstruction and stabilization are required. All approaches and related anatomy are very well described and illustrated. In sacral tumors, bladder and bowel dysfunction arising from aggressive surgical resection is a “small price to pay,” considering the high recurrence rate of incomplete resections. Similar to their skull base counterparts, chordomas and chondrosarcomas of the spine and sacrum are best treated by postoperative high-dose radiotherapy to reduce the rate of local recurrence. Recent technological advances allow better radiation delivery and targeting, with reduced toxicity to nearby normal tissues.
In conclusion, this book represents a comprehensive compilation of current literature, approaches, techniques, and therapeutic options for patients with chordomas and chondrosarcomas of the skull base and spine. Including 20 tables and 427 illustrations, the book is also appropriately priced and should appeal not only to neurosurgeons but also to orthopedic spine surgeons and radiation therapists who treat patients with these tumors.