Session moderator Howard A. Fine, MD, the Anne Murnick Cogan and David H. Cogan Professor of Oncology and Director of the Brain Tumor Center at New York University Cancer Institute, shared his enthusiasm over the findings of the RTOG 9802 study. “I don’t know of any other tumor type where the addition of chemotherapy has had such a profound extension of survival in a disease we usually think of as chemotherapy-resistant,” he said. “That is remarkable.”

Management Questions

Martin J. van den Bent, MD, Professor of Neuro-oncology at Erasmus Cancer Center in the Netherlands, was the study’s formal discussant at the ASCO Annual Meeting. He said that a number of management questions remain for low-grade gliomas. What is the role of “watch and wait” and when should radiotherapy and chemotherapy be initiated? Since starting radiotherapy prematurely can lead to more harm than good, many specialists tend to postpone radiotherapy when possible, sometimes using chemotherapy first, but acknowledging that only a minor response is expected, he said.

According to RTOG 9802, the trade-off may be a reduction in survival, he said. “Today, this study helps answer some of these questions…. We can safely conclude that adjuvant PCV after radiotherapy improves overall survival in patients with low-grade, high-risk (age > 40, subtotal resection) gliomas,” he said. “There are not many studies in which such a magnificent increase in survival has been reported.”

While this study demonstrated benefits in “all comers,” of interest will be the analysis by histology and molecular status, he said.

Question of Relevance

Dr. van den Bent further noted that the restuls of RTOG 9802 are in line with two other adjuvant PCV trials that initially reported a negative overall survival endpoint (despite increases in progression-free survival), but with long-term follow-up achieved at least a 40% reduction in deaths. “This was due to a striking similarity in the late separation of the curves 4 to 6 years after randomization,” he pointed out.

But in spite of three positive PCV trials, the question of relevance must be raised, Dr. van den Bent said. “Most of us have moved on to temozolomide. Is it equivalent to PCV? We assume so, and we agree it is less toxic and better tolerated, but we don’t have the data.”

To help answer this, the CODEL study is comparing PCV to temozolomide in anaplastic oligodendrogliomas with codeletions of 1p/19q. ■

Disclosure: Dr. Fine reported no potential conflicts of interest. Dr. van den Bent is on the speakers bureau of MSD.