{'fraction_non_alphanumeric': 0.03311867525298988, 'fraction_numerical': 0.01839926402943882, 'mean_word_length': 5.359649122807017, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Chordomas of the craniocervical junction: follow-up review and prognostic factors.

OBJECT
Chordomas are rare tumors that arise from the remnants of the notochord. Because of their deep location, local infiltrative nature, and involvement of surrounding bone, treatment of chordomas is a challenge. In this study the authors analyze the data and prognostic factors obtained during the follow-up period (range 1-150 months, median 38 months) in 53 patients with craniocervical junction chordomas and 10 patients with chondrosarcomas.


METHODS
Several surgical approaches were used, and some tumor excisions required staged procedures. Survival was calculated according the Kaplan-Meier method. Statistical analysis was performed using Fisher exact, log rank and Kruskal-Wallis tests. Radical/subtotal resection was achieved in 77.8% of the patients. The mortality rate during the follow-up period was 14.3%. In patients harboring chondrosarcoma better 5-year recurrence-free survival (RFS) rates were demonstrated than in those with chordoma (100% and 50.7%. respectively). Histological patterns (typical or chondroid chordomas) and patient age at onset of symptoms had no effect on the RFS rates. Radical/subtotal resections were associated with better RFS rates than partial resection. Adjuvant proton-beam therapy was shown to increase the RFS rates compared with conventional radiotherapy (90.9% and 19.4%, respectively, at 4 years posttreatment). Karyotypically abnormal tumors were associated with the worst RFS rates compared with karyotypically normal lesions (44.5% and 90.3%, respectively, at 3 years). Cases of cranial nerve palsy followed by those with cerebrospinal fluid leakages were the most frequent postoperative complications. Permanent postoperative neurological deficit was observed in 28.6% of the patients.


CONCLUSIONS
A better prognosis was observed in patients with chondrosarcoma compared with those harboring chordoma. Histological pattern and patient age at symptom onset were not factors that influenced prognosis in cases of chordoma. Extensive resection and possibly adjuvant proton-beam therapy provided better prognoses for these patients.