Original Publication Date: 28 May, 2015
Publication / Source: Oncology Central
Authors: Marc C Chamberlain, University of Washington Seattle, WA, USA
The treatment of gliomas, regardless of the World Health Organization (WHO) grade, continues to evolve and recent studies suggest an improvement in patient outcomes as assessed by overall survival as well as an improved understanding of the molecular biology of gliomas. Several large glioma trials have been reported recently and in many instances have changed clinical practice.
Low grade gliomas (LGG), i.e., WHO grade II gliomas, are comprised of three classic histologies; astrocytoma, oligodendroglioma and oligoastrocytoma (an admixture of oligodendroglioma and astrocytoma). In addition, LGG are further characterized as either low risk or high risk wherein high risk is defined as either age of patient >40 years or having undergone an incomplete tumor resection. This later definition is based on the recently reported RTOG 9802 trial, which compared radiotherapy (RT) with RT + PCV (procarbazine, lomustine, and vincristine) chemotherapy . Previously, and based upon two large European studies, high risk was defined as a patient having three of five characters, including age >40 years, tumor >5 cm in diameter, tumor involving midline brain, astrocytic histology or focal neurological deficit preceding any tumor treatment .
RTOG 9802 changed practice by demonstrating that in patients defined as having high-risk LGG, the administration of RT + PCV improved both median progression-free survival (PFS) and overall survival (OS) by two fold. RTOG 9802 reported both PFS (4 vs 7.8 years) and OS (7.8 years vs 13.3 years) were significantly improved in the RT + PCV treatment arm. The mean follow-up in this study was 11.9 years and 55% of all enrolled patients had died. Furthermore, as the RTOG data matures as demonstrated by the 10-year OS data, the difference between treatment arms continues to separate, further favoring the combination treatment.