A 31-year-old woman with a transformed low-grade glioma

Low-grade gliomas in adults have an incidence of 0.8 to 1.2 per 100,000, and their causes are unknown. Despite their histological classification as low-grade, they cannot be cured by any current treatment mode, and no class I evidence exists to guide initial treatment of these tumors. Median survival ranges between 7.5 years and 10 years, with a 5-year survival probability between 55% and 86%. The prognosis depends on age, World Health Organization (WHO) tumor grade, Karnofsky performance score, cytological type (oligodendroglioma vs astrocytoma), and, potentially, the extent of resection. Oligodendrogliomas with loss of heterozygosity on chromosomes 1p and 19q have a distinctly more favorable prognosis and therapeutic response rate. Low-grade tumors progress to high-grade gliomas with aggressive biological behavior at increasing frequency with advancing age. Ms P is a young woman with a previously treated oligodendroglioma, WHO grade II, with loss of heterozygosity on chromosomes 1p and 19q, which at a third resection had transformed into an oligodendroglioma of WHO grade III. She wants to know her current and future therapeutic options.