Chordomas are slow-growing malignant neoplasms. Determination of histopathologic prognostic factors using a large cohort study has been limited by their low incidence. In this retrospective study, we investigated the clinical, histopathologic, and immunohistochemical prognostic factors in 287 chordomas from 111 patients assessed by central pathologic review. Expression patterns of a variety of markers, including vascular endothelial growth factor (VEGF), mTOR pathway, c-kit, HER2, epidermal growth factor receptor (EGFR) and STAT3, and KRAS, BRAF, EGFR, and PIK3CA mutations were analyzed. On univariate analysis, the results confirm surgery as the best treatment, as judged by patient progression-free survival (PFS) and overall survival (OS). Proton therapy, the presence of a dedifferentiated component, mitotic figures, and Ki67 and p53 labeling indices correlated with PFS . Necrosis and apoptosis correlated with OS. Based on these findings, we propose a histopathologic grading system that correlates with PFS and OS. On multivariate analysis, extent of resection, tumor grade, and proton therapy were independent prognostic factors of PFS; extent of resection, tumor location, and grade were independent prognostic factors of OS. Based on the expression of EGFR, pSTAT3, VEGF, and mTOR pathway proteins, (in 85.9%, 79.1%, 85.7%, and 46% of chordomas, respectively), and 2 new mutations in the PIK3CA gene, we also provide evidence for potential therapeutic targets.

Many different pathologies derived from the notochord can be observed: some are remnants, some may be precursors of chordomas and some have similar features but are probably not genuine chordomas. To-day, immuno-histological studies should permit to differentiate them from real chordomas. Improving knowledge of molecular biology raises hopes for complementary treatments but to date the quality of surgical resection is still the main factor of prognosis. Complementary protontherapy seems useful, especially in skull base chordomas, which have better overall results than those of the craniocervical junction and of the cervical spine. However, we are still lacking an intrinsic marker of evolution to differentiate the slow growing chordomas with an indolent evolution from aggressive types leading rapidly to recurrence and death on which more aggressive treatments should be applied.

Pediatric chordomas are rare malignant neoplasms, and few data are available for optimizing therapeutic strategies and outcome. This study aimed at evaluating how best to manage them and to identify prognostic factors. This multicentric retrospective study included 40 children diagnosed with chordomas between 1966 and 2012. Clinical, radiological, and histopathological data, treatment modalities, and outcomes were reviewed. The median age was 12 years old. Most chordomas were histologically classical forms (45.5%) and were mostly located at the skull base (72.5%). The overall survival (OS) was 66.6% and 58.6%, and progression-free survival (PFS) was 55.7% and 52% at 5 and 10 years, respectively. Total resection was correlated with a better outcome (p = 0.04 for OS and PFS, log-rank). A histopathological/immunohistochemical grading system recently crafted for adults was applied. In a multivariate analysis, it significantly correlated with outcome (PFS and OS, p = 0.004), and the loss of BAF47 immunoexpression appeared to be a significant independent prognostic factor (PFS, p = 0.033). We also identified clinical and histopathological parameters that correlated with prognosis. A new grading system combined with the quality of surgical resection could help classify patients to postpone radiotherapy in case of low risk. Targeted therapy and reirradiation at recurrence may be considered as potential therapeutic strategies.

These oncological and functional results of awake glioma surgery during the learning curve are comparable to results from established centers. The use and utility of resection probability maps are well demonstrated. The return to work level is high.

In this paper, we show that Klinger dissection with preservation of pial membranes provides a realistic model of insular surgery, allowing surgeons to learn and train on this highly specialized surgery.