RTHP-29. HYPOFRACTIONNATED RADIOTHERAPY FOR REFRACTORY SKULL BASE CHORDOMA

Abstract

Abstract OBJECTIVE Skull base chordoma is difficult to be totally excised by surgery because of the complex anatomical structures of skull base. Postoperative radiotherapy is one of the most important treatment options for skull base chordoma. However, the response of chordoma to conventional fractionation radiotherapy is poor. Therefore, it is of great value to explore the therapeutic effects of hypofractionnated radiotherapy for refractory skull base chordoma. METHODS A retrospective analysis was performed on the clinical data of patients with refractory skull base chordomas who were admitted to Guangdong Sanjiu Brain Hospital from 2007 to April 2019. The characteristics of the selected cases and prognosis-related factors were analyzed with Kaplan-Meier method. RESULTS A total of 21 patients were enrolled in this study, including 11 male (52.4%) and 10 female (47.6%). Twenty patients received surgery, including gross total resection in 5 cases (25%), subtotal resection in 14 cases (70%) and biopsy in 1 case (5%). Among 18 patients who received radiotherapy, 17 (94.4%) received radiotherapy after the first diagnosis; 1 (5.6%) were treated with radiotherapy after tumor recurrence; and 3 (16.7%) received the secondary radiotherapy after tumor recurrence. The median overall survival of 11 patients receiving hypofractionnated radiotherapy (45-60Gy/8-20F) and 7 patients receiving conventional fractionation radiotherapy (40-60Gy/20-30F) reached 33 months (7–130) and 68 months (27–105), respectively. The results of Kaplan-Meier analysis revealed that the overall survival of patients who were treated with hypofractionnated radiotherapy was significantly longer than that of those receiving conventional fractionation radiotherapy. No one suffered from radiation-induced acute brain injury (≥grade 3), and only 1 patient who received hypofractionnated radiotherapy developed radiation-induced brain necrosis at 3 years after hypofractionnated radiotherapy. CONCLUSION Hypofractionnated radiotherapy for refractory skull base chordoma can not only achieve a therapeutic effect, but also reduce the risk of radiation-induced necrosis.