2025 Proffered Presentations
S372: TWO DECADES OF SKULL BASE CHONDROSARCOMA MANAGEMENT: INSIGHTS FROM LARIBOISIÈRE HOSPITAL
Jonathan Chainey, MD, MSc; Konstantina Kavoura, MD; Jerold Justo, MD; Arianna Fava, MD; Thibault Passeri, MD; Sebastien Froelich, MD, PhD; Lariboisière Hospital, Assistance Publique-Hôpitaux de Paris, University of Paris
Objective: Chondrosarcomas (CS) are rare malignant tumors and represent only 6% of skull base tumors. Surgical resection and adjuvant radiotherapy are the main treatment options for this disease. In this study, the authors present their experience in managing skull base chondrosarcomas over a 21-year period.
Methods: A retrospective study of skull base chondrosarcomas surgically treated at Laribroisière Hospital from 2002 to 2023 was conducted. Patients’ demographics, clinical presentation, preoperative MRI characteristics, extent of resection (EOR), postoperative course and follow-up information were collected. This study focuses on factors influencing the extent of resection (EOR) and the predictors from tumor recurrence and patient survival.
Results: A total of 74 surgical procedures were performed in 67 patients (35F/32M). Mean age at diagnosis was 41 years-old and 46% of patients received previous treatment at another institution prior to our management. Based on volumetric MRI measurement, gross total resection (GTR), near-total resection (NTR), subtotal resection (STR) and partial resection (PR) was achieved in 18 cases (27%), 9 cases (13%), 17 cases (25%), and 14 cases (21%), respectively. EOR was not available for 9 cases (13%). Tumor location influenced the EOR (p = 0.018) and new or worsened postoperative cranial nerve palsy was significantly associated with higher EOR (p = 0.04). The average follow-up from diagnosis and surgery was 87.6 months and 47.4 months, respectively. Recurrence occurred in 17 patients, with a mean time to recurrence of 31.4 months and surgery was performed in 59% of the recurrence cases. The 5-year-progression-free survival (PFS) rate was 68.4%. Factors like age over 40, WHO grade 1, tumor locations, and the absence of postoperative adjuvant therapy (photons and protons radiotherapy) were factors associated with tumor recurrence (p = 0.013, p = 0.022, p = 0.0002, and p = 0.0352, respectively). In contrast, EOR did not affect recurrence rates. The overall survival (OS) rate was 87% and was improved for patients with chondrosarcoma WHO grade 2 and who received proton beam radiotherapy (PBRT) or a combination of photons and protons radiation therapy postoperatively (p < 0.0001 and p = 0.0222, respectively).
Conclusion: This study showed that while chondrosarcomas have a relatively low mortality rate, the risk of recurrence remains significant. The findings suggest that postoperative adjuvant combination of photos and protons radiation therapy can reduce recurrence risk. This study also questions the prioritization of EOR over quality of life due to the associated risks of cranial nerve injuries without clear benefits in reducing recurrence. Interestingly, higher WHO grades didn’t predict worse outcomes suggesting molecular markers might offer superior prognostic value than histological grading.
