Vivien Fung1, Valentin Calugaru2, Stéphanie Bolle3, Hamid Mammar2, Claire Alapetite2, Philippe Maingon4, Ludovic De Marzi2, Sébastien Froelich5, Jean-Louis Habrand6, Rémi Dendale2, Georges Noël7, Loïc Feuvret8. 1. Department of Radiation Oncology, Institut Curie - Centre de protonthérapie d'Orsay (CPO), France; Department of Radiation Oncology, CHU Amiens site SUD, France. Electronic address: fungvivien100@hotmail.com. 2. Department of Radiation Oncology, Institut Curie - Centre de protonthérapie d'Orsay (CPO), France. 3. Department of Radiation Oncology, Gustave Roussy, Villejuif, France. 4. Department of Radiation Oncology, groupe Pitié-Salpêtrière (Assistance Publique - Hôpitaux de Paris), France. 5. Department of Neurosurgery, Hôpital Lariboisière (Assistance Publique - Hôpitaux de Paris), France. 6. Department of Radiation Oncology, Centre François Baclesse, 14000 Caen, France. 7. Department of Radiation Oncology, Centre Paul Strauss, Strasbourg Cedex, France. 8. Department of Radiation Oncology, Institut Curie - Centre de protonthérapie d'Orsay (CPO), France; Department of Radiation Oncology, groupe Pitié-Salpêtrière (Assistance Publique - Hôpitaux de Paris), France.
Abstract
BACKGROUND AND PURPOSE: To evaluate clinical results and safety of a dose adaptive protocol based on tumor volume coverage and critical structure constraints, for the treatment of skull base chordomas. MATERIAL AND METHODS: Between May 2006 and October 2012, 106 patients with skull base chordoma were treated by combined photon and proton irradiation. Prescribed dose levels were 68.4, 70.2, 72 and 73.8 Gy(RBE) in once daily fractionation of 1.8 Gy(RBE). Dose level and dosimetric constraints to organs at risk depended on postoperative residual Gross Tumor Volume (GTV) coverage. Local control (LC) and overall survival (OS) were evaluated using the Kaplan-Meier method. RESULTS: With a median follow-up of 61 months, the 2-year, 4-year, and 5-year LC rates were 88.6%, 78.3%, and 75.1%, respectively. GTV > 25 mL (p = 0.034, HR = 2.22; 95%CI 1.06-4.62) was an independent unfavorable prognostic factor of LC. The 2-year, 4-year, and 5-year OS rates were 99%, 90.2%, and 88.3%, respectively. Grade 3-5 late toxicity was observed in 7 patients, resulting in 93% 5-year freedom from high-grade toxicity. CONCLUSIONS: This study suggests that the probability of LC of skull base chordomas depends on postoperative GTV. The dose adaptive protocol achieves acceptable local control. Future studies should investigate whether further dose escalation to doses in excess of 74 Gy(RBE) would achieve better results.
BACKGROUND AND PURPOSE: To evaluate clinical results and safety of a dose adaptive protocol based on tumor volume coverage and critical structure constraints, for the treatment of skull base chordomas. MATERIAL AND METHODS: Between May 2006 and October 2012, 106 patients with skull base chordoma were treated by combined photon and proton irradiation. Prescribed dose levels were 68.4, 70.2, 72 and 73.8 Gy(RBE) in once daily fractionation of 1.8 Gy(RBE). Dose level and dosimetric constraints to organs at risk depended on postoperative residual Gross Tumor Volume (GTV) coverage. Local control (LC) and overall survival (OS) were evaluated using the Kaplan-Meier method. RESULTS: With a median follow-up of 61 months, the 2-year, 4-year, and 5-year LC rates were 88.6%, 78.3%, and 75.1%, respectively. GTV > 25 mL (p = 0.034, HR = 2.22; 95%CI 1.06-4.62) was an independent unfavorable prognostic factor of LC. The 2-year, 4-year, and 5-year OS rates were 99%, 90.2%, and 88.3%, respectively. Grade 3-5 late toxicity was observed in 7 patients, resulting in 93% 5-year freedom from high-grade toxicity. CONCLUSIONS: This study suggests that the probability of LC of skull base chordomas depends on postoperative GTV. The dose adaptive protocol achieves acceptable local control. Future studies should investigate whether further dose escalation to doses in excess of 74 Gy(RBE) would achieve better results.
Authors: Stella K Yoo; Ben A Strickland; Gabriel Zada; Shelly X Bian; Adam Garsa; Jason C Ye; Cheng Yu; Martin H Weiss; Bozena B Wrobel; Steven Giannotta; Eric L Chang Journal: J Neurol Surg B Skull Base Date: 2020-01-14
Authors: Adam L Holtzman; Ronny L Rotondo; Michael S Rutenberg; Daniel J Indelicato; Alexandra De Leo; Dinesh Rao; Jeet Patel; Christopher G Morris; William M Mendenhall Journal: Int J Part Ther Date: 2021-06-25