Nanocarrier based Targeted Drug Delivery for Treatment of Brain Tumor

Brain tumors refer to a heterogeneous group of primary and metastatic neoplasms in the central nervous system and are one of the life-threatening diseases which are characterized by low survival rate (1). According to GLOBOCAN 2018, nearly 296,851 new cases of brain and nervous system tumors and 241037 deaths are diagnosed in 2018 worldwide. In India 28142 new brain tumor cases annually are reported while deaths were 24003 in 2018 (2). The estimated incidence, mortality and 5 year prevalence of brain tumor among men in India is approximately 11855, 9574 and 17251 respectively which represents 2.5%, 2.7% and 2.6% of Indian population respectively while for women it is 6976 (1.3%), 5578 (1.7%) and 10157 (1%) respectively. More than 120 types of brain tumors are identified till date and depending on the origin of tumor, most common tumors are grouped as tumors of neuroepithelial tissue, tumors of cranial and spinal nerve, tumors of meninges, heamopoitic origin neoplasm and lymphomas, tumor of sellar region, germ cell tumors and cysts (3,4). The most prevalent brain tumors are intracranial metastases from systemic cancers, meningiomas, and gliomas, specifically, glioblastoma (1,5). Glioma is the most frequent primary brain cancer which accounts for 29% of all primary brain and CNS tumors and 80% of alignant brain tumors. These malignant gliomas are primary tumors that are derived from glial origin and account for approximately 70% of new primary brain cancer diagnosis. The classification, grading, and treatment of this diverse group of tumors have been primarily based on morphological criteria, which introduced a certain degree of interpretative subjectivity and moreover provided only suboptimal accuracy for the prediction of treatment response (6). WHO has classified glioma in three category viz. astrocytoma, oligodendrogliomas and mixed gliomas (oligoastrocyotomas). Amongst gliomas, glioblastomamultiforme (GBM) which is a grade IV astrocytoma according to the World Health Organization (WHO) classification, is the most common and aggressive form of glioma in nature (3,6). The median survival for glioblastoma is 14 months (7). The high mortality rate due to GBM can be attributed to specific properties of glioma which includes highly infiltrative nature and lack of clear margin. The existing therapy for GBM is nonspecific and almost fails to prevent reoccurrence of disease.