Certified Neuroscience Registered Nurse (CNRN) Practice Exam

Which primary malignant brain tumor is known to be responsive to chemotherapy?

1. Astrocytoma

2. Medulloblastoma

3. Oligodendroglioma

4. Glioblastoma

The correct answer is: Oligodendroglioma

Oligodendroglioma is recognized for its responsiveness to chemotherapy, particularly when associated with the presence of specific genetic alterations, such as co-deletion of chromosomal arms 1p and 19q. This genotype not only indicates a better prognosis but also makes oligodendrogliomas particularly sensitive to treatment with agents like procarbazine, CCNU (lomustine), and vincristine. In contrast, other primary malignant brain tumors, while they may have some response to treatment, are generally less responsive to standard chemotherapy regimens. For instance, glioblastoma, one of the most aggressive brain tumors, has a limited response to chemotherapy and is often treated with a combination of surgery, radiation, and the chemotherapeutic agent temozolomide, but the overall efficacy is modest. Astrocytomas can also demonstrate variable responses depending on their grade, but typically higher-grade astrocytomas like glioblastomas do not respond well to chemotherapy. Medulloblastomas, while pediatric tumors that can respond to chemotherapy, are not the best example of a primary malignant brain tumor in adults responsive to chemotherapy like oligodendroglioma. Thus, oligodendroglioma stands out due to its unique genetic characteristics, which