Patterns of care and outcomes of multi-agent versus single-agent chemotherapy as part of multimodal management of low grade glioma

For high-risk low-grade gliomas (LGGs), adjuvant radiotherapy (RT) with procarbazine/lomustine/vincristine (PCV) chemotherapy increases overall survival (OS) over RT alone. However, in practice, temozolomide (TMZ) is often used instead of PCV. Using the National Cancer Data Base (NCDB), we provide the first investigation of practice patterns and outcomes of chemoradiotherapy with single-agent chemotherapy (SAC, analogous to TMZ) or multi-agent chemotherapy (MAC, analogous to PCV) for LGG. Patients with high-risk Grade II LGGs were queried in the NCDB. Inclusion was limited to patients treated with definitive RT and chemotherapy. Patients were divided into cohorts receiving SAC or MAC. Kaplan-Meier analysis compared overall survival (OS), and Cox proportional hazards models determined variables independently associated with OS. Of 1029 patients, 989 (96.1%) received SAC, while 40 (3.9%) received MAC. Patients treated more recently (2010-2012) were less likely to receive MAC (p = 0.029). No differences in median OS were observed between patients treated with MAC and SAC (45.3 vs. 59.2 months, p = 0.861). Independent predictors of worse OS included age >40, high Charlson-Deyo index, other governmental/unrecorded insurance status, biopsy only, astrocytoma histology, Western geographical region, and higher income. Substuting MAC with SAC had no impact on OS (p = 0.804). There is a significantly greater utilization of SAC compared to MAC in the US. There were no differences in OS between patients receiving SAC and MAC, nor did this factor impact OS on multivariate analysis, suggesting that the practice of substituting MAC with SAC for management of LGG may not adversely affect outcome.