Peer-Review ReportSkull Base Chordoma and Chondrosarcoma: Influence of Clinical and Demographic Factors on Prognosis: A SEER Analysis
Introduction
Chordomas and chondrosarcomas are rare skull base tumors with a combined incidence of 0.02/100,000 a year, with similar radiographic and clinical presentations (32). Although rare, these tumors comprise a large proportion of skull base tumors and are locally invasive (4). Chondrosarcomas are thought to carry a better prognosis; however, data for outcomes of both tumors are varied, and comparative natural history data also are limited 1, 4, 9, 18, 23. The rarity of these skull base tumors limits understanding of the natural history of these tumors and hinders prospective study of antitumoral therapies.
Although the 2 have not been compared in rigorous studies, chordomas of the skull base generally are reported to have worse prognosis than chondrosarcomas 4, 18. For both tumors surgical resection remains the accepted primary treatment, and there are many reports that maximizing the extent of resection reduces recurrence risk and improves survival 1, 18, 23, 28. Postoperative radiation frequently is used in these tumors, particularly in cases of incomplete resection, and has been reported to reduce the risk of recurrence 5, 16. No randomized trials of radiation therapy in skull base chordomas or chondrosarcomas have been completed, and the variability in patterns of care in single-center series presents a challenge for meta-analytic methods in determining the impact of postoperative radiation therapy on outcome in these rare and frequently slow-growing tumors.
The Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute is a population-based registry that contains tumor data for approximately 10%–26% of the U.S. population. The goal of this study was to better understand the clinical and demographic factors influencing survival for skull base chordomas and chondrosarcomas by use of the SEER database to enable more informed clinical management of these lesions and to identify knowledge gaps to guide future trial design.
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Patient Selection
Patients with a diagnosis of chordoma and chondrosarcoma were identified using the SEER database. Patients from the 1983–1988, 1988–2003, and 2004–2009 data sets were screened for a diagnosis of chordoma, chondroid chordoma, dedifferentiated chordoma, chondrosarcoma, chondroblastoma, myxoid chondrosarcoma, mesenchymal chondrosarcoma, and clear cell chondrosarcoma including histology codes 9220–9242 and 9370–9372. Chordomas and chondrosarcomas involving the skull (C41.0), brainstem (C71.7),
Results
A total of 685 patients were included in the study; 416 patients had chordomas and 269 had chondrosarcomas. Chordoma and chondrosarcoma patients were similar with regard to age, race, and sex (Table 1). Chondrosarcomas were more likely to be larger; 68.9% of chondrosarcomas were ≥4 cm at presentation compared with only 41.2% of chordomas (P < 0.0001). The rate of radical resection was slightly greater for patients with chondrosarcoma (36.8%) than those with chordoma (29%), although this
Discussion
Recent systematic reviews of the literature estimate the overall 5-year survival for patients with skull base chondrosarcoma to be 89% and progression-free survival 80% 4, 5. These rates compare favorably to the 5-year rates reported in a recent meta-analysis by Di Maio et al. (18) of patients with skull base chordoma of 78% overall survival and 51% progression-free survival. Surgery remains the initial treatment of choice for patients with skull base chordomas and chondrosarcomas. Di Maio
Conclusion
A study of the SEER data for patients with skull base chordomas and chondrosarcomas confirms the improved survival of patients with chondrosarcomas, despite the similarities in clinical presentation and radiographic appearance of these 2 tumors. In chondrosarcomas, older age, earlier decade of diagnosis, and mesenchymal subtype were associated with worse overall survival. In chordomas, older age and larger tumors were associated with worse prognosis. In both tumor types, survival was markedly
References (32)
- et al.
Proton beam therapy in skull base pathology
Otolaryngol Clin North Am
(2011) - et al.
A systematic review of intracranial chondrosarcoma and survival
J Clin Neurosci
(2009) - et al.
Challenges in linear accelerator radiotherapy for chordomas and chondrosarcomas of the skull base: focus on complications
Int J Radiat Oncol Biol Phys
(2012) - et al.
Proton radiation therapy for chordomas and chondrosarcomas of the skull base
Neurosurg Clin N Am
(2000) - et al.
Effectiveness of carbon ion radiotherapy in the treatment of skull-base chordomas
Int J Radiat Oncol Biol Phys
(2007) - et al.
Carbon ion radiotherapy of skull base chondrosarcomas
Int J Radiat Oncol Biol Phys
(2007) - et al.
Chordoma: current concepts, management, and future directions
Lancet Oncol
(2012) - et al.
Results of spot-scanning proton radiation therapy for chordoma and chondrosarcoma of the skull base: the Paul Scherrer Institut experience
Int J Radiat Oncol Biol Phys
(2005) - et al.
Chordoma and chondrosarcoma: similar, but quite different, skull base tumors
Cancer
(2007) - et al.
Proton therapy in chordoma of the base of the skull: a systematic review
Neurosurg Rev
(2009)
Cranial chondrosarcoma and recurrence
Skull Base
Current clinical evidence for proton therapy
Cancer J
Photon-based fractionated stereotactic radiotherapy for postoperative treatment of skull base chordomas
Am J Clin Oncol
Intracranial chordomas: a clinicopathological and prognostic study of 51 cases
J Neurosurg
Chordomas and chondrosarcomas of the cranial base: results and follow-up of 60 patients
Neurosurgery
Gamma knife surgery for skull base chordomas and chondrosarcomas
J Neurosurg
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2022, World NeurosurgeryCitation Excerpt :However, most studies had focused solely on 1 tumor type. Skull base chondrosarcomas were thought to result in a better prognosis than chordomas.2,10 However, the survival of patients with chondrosarcoma versus chordoma in other locations has been less well explored.
Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.