Clivus chordomas: a systematic review and meta-analysis of contemporary surgical management.
BACKGROUND
Chordomas are rare bony lesions arising from notochordal remnants. Technical advances in endoscopic surgery have allowed the median endonasal corridor to be used for a larger number of chordoma cases. However, very few studies have critically examined the data in support of the anterior midline approach (AMA), as compared to lateral and posterolateral transcranial corridors.


METHODS
A systematic search of the literature was done in March 2016 using EMBASE and PubMed for articles published between January 2006 and March 2016 to identify surgical series of clivus chordomas. Only articles describing chordomas cases arising from the clivus of craniocervical junction were included in the analysis.


RESULTS
Twenty-seven articles were included in this systematic review, amounting to a total of 1050 patients. The weighted mean rate of GTR was 39.9% (range 0-78.3%) in this patient population. The surgical approaches were described in 16 papers, with 6 series reporting on surgeries done exclusively through the midline corridor (116 patients). In the remaining 10 series (495 patients), the AMA was used in a mean of 56.8% of cases. In studies including patients operated solely through an AMA, a higher GTR rate was obtained (60.7% vs. 42.0%). Postoperative complications were also different between the two cohorts, with lower cranial nerves deficits and CNS infections but higher incidence of CSF leak in the AMA group than in mixed surgical series. In a weighted mean follow-up time of 52.1±21.9 months, recurrences were observed in 38.2% of the total population of patients. Among 423 patients, the weighted 5-year PFS was 49.9±12.1% and the 5-year OS was 73.9±11.2% (N.=391). A random effects model was performed, combining data from studies reporting recurrence rates in GTR and non-GTR (N.=610), with a total odds ratio of having a recurrence for patients who had GTR vs non-GTR of 0.289 (95CI 0.184-0.453).


CONCLUSIONS
In this systematic review and meta-analysis of studies published in the last decade, an estimated 5-year PFS of 49.9% and 5-year OS of 73.9% were obtained. The weighted mean GTR rate in the included study was 39.9%, with a significantly reduced occurrence of recurrence in complete resections. Although anterior midline approaches may allow for higher GTR rates and fewer neurological morbidity than traditional transcranial routes, their impact of long-term survival and disease control remains largely unknown.
Department of Neurosurgery, Hôpital Lariboisière, Paris, France - Sebastien.froelich@aphp.fr.
Moujahed
M
Labidi
Kentaro
K
Watanabe
Schahrazad
S
Bouazza
Damien
D
Bresson
Anne L
AL
Bernat
Bernard
B
George
Sébastien
S
Froelich
D002817:Chordoma / Q000601:surgery*; D003388:Cranial Fossa, Posterior / Q000473:pathology / Q000601:surgery*; D006801:Humans; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000601:surgery*; D011183:Postoperative Complications / Q000473:pathology / Q000601:surgery*; D019292:Skull Base Neoplasms / Q000601:surgery*; D016896:Treatment Outcome