Advances in radiation therapy in malignant brain tumors

Abstract

Radiation therapy (RT) plays a key role in the optimal management of a range of primary and secondary brain tumors. RT has evolved from conventional radiotherapy to three-dimensional (3D) conformal, intensity-modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), stereotactic techniques such as stereotactic radiosurgery or fractionated stereotactic radiotherapy to particle beam therapies such as the proton beam therapy (PBT) and carbon ion therapy. Further, there is increased evidence of molecular-based approach in the treatment of malignant brain tumors. Tumors such as the high-grade gliomas tend to have inferior outcomes as compared to the low-grade gliomas. Pediatric brain tumors tend to do better, in terms of local control, progression-free survival, and overall survival. In such scenarios, sparing of critical structures is essential as it tends to reduce the dose to the normal brain tissue, thereby improving neurocognitive outcomes, reduces hormonal impairment and risk of secondary malignant neoplasms. Modern techniques such as the IMRT, VMAT, and PBT, especially image-guided intensity-modulated proton therapy, spare the critical structures to bare minimum, which in turn leads to superior dose distribution without any low dose spillage to the nearby areas. These advanced techniques not only behave therapeutically but are also cost-effective, resulting in improved quality of life.