The Cox model identified the RT-plus-PCV arm as a favorable prognostic variable for both OS (P = 0.001; HR, 0.56) and PFS (P < 0.001; HR, 0.46). Patients with mixed oligoastrocytoma versus oligodendroglioma had worse OS (P < 0.001; HR 2.06), as did those with astrocytoma compared with oligodendroglioma (P < 0.001; HR, 2.54); for PFS, the corresponding values were P < 0.001; HR, 1.87 and P < 0.001; HR, 2.18, respectively. Overall survival—but not PFS—was worse for males than females (P = 0.018; HR, 1.53).
Toxicity, although greater with the RT-plus-PCV combination, was acceptable, and similar to that seen with many combination chemotherapy regimens commonly in use. This included fatigue, weight loss, hematologic and gastrointestinal tract toxicity, and late radiotherapy toxicity.
“Severe cognitive impairment at 5 years, as measured by MMSE [mini-mental state examination], is infrequent,” he said. Categorical change in MMSE by treatment arm showed that at year 5, 12% of patients had a gain in score in the RT-plus-PCV arm compared with 5% in the RT-alone arm; 80% versus 96% had no change; and 8% and 0% had a decline, respectively.
“This trial could only have been accomplished through a publicly or philanthropically supported research network,” Dr. Bucker concluded, adding that future plans include assessment of treatment effect by histologic type; by molecular markers, including 1p/19q co-deletion, IDH mutations, and genomic analyses; and germline polymorphisms.
The discussant for this presentation, Martin J. van den Bent, MD, of Erasmus University Medical Center, Rotterdam, The Netherlands, said that as of 2014, the role of adjuvant chemotherapy after or with RT has been established in all diffuse glioma types and that understanding of the molecular subtypes that benefit from adjuvant chemotherapy has increased. The RTOG 9802 study, he said, “demonstrates benefit for low grade glioma ‘all-comers’.”
- Buckner JC, Pugh SL, Shaw EG et al. Abstract 2000. Presented at: 2014 American Society of Clinical Oncology (ASCO) Annual Meeting; May 30-June 3, 2014; Chicago, IL.