Long-term outcome of adjunctive Gamma Knife radiosurgery in skull-base chordomas and chondrosarcomas: An Indian experience

•Skull-base Chordomas (CD) and Chondrosarcomas (CS) should be treated with radical safe surgical resection followed by adjunctive Radiotherapy (RT) for residual tumor.•Better 5-year progression-free survival (PFS) with Gamma Knife Radiosurgery (GKRS) in skull-base CD/CS is associated with CS histopathology, age < 45 years, margin dose > 16 Gy, tumor volume < 7 cm3 (p-value < 0.05) and gross total resection.•Brachyury positivity was associated with better 5-year PFS in skull-base CD.