In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 37, No. 15_suppl ( 2019-05-20), p. 2002-2002
Abstract:
2002 Background: This study sought to update the predictive significance of the three WHO-defined molecular glioma subgroups ( IDHwt, IDHmt/noncodel, and IDHmt/codel) in the subset of specimens available for analysis in NRG Oncology/RTOG 9802, a phase III trial of high-risk low-grade gliomas (LGGs) treated with radiation (RT) with and without PCV after biopsy/surgical resection. Notably, this is the first phase III study to evaluate the predictive value of the WHO subgroups in LGGs using prospectively-collected, well-annotated long-term overall survival data, in a post-hoc analysis. Methods: IDH1/2 mutation status was determined by immunohistochemistry and/or next-generation sequencing. 1p/19q status was determined by Oncoscan and/or 450K methylation data. Treatment effects on overall survival (OS) and progression-free survival (PFS) by marker status were determined by the Cox proportional hazard model and tested using the log-rank test in a secondary and exploratory analysis. Results: Of all the randomized eligible high-risk G2 patients (N = 251) in NRG Oncology/RTOG 9802, 106(42%) patients had tissue available with sufficient quality DNA for profiling. Of these, 80(75%) were IDHmut; 43(41%) were IDHmut/non-co-deleted, 37(35%) were IDHmut/co-deleted, and 26(24%) were IDHwt. Upon univariate analyses, no significant difference in either PFS or OS was observed with the addition of PCV in the IDHwt subgroup. Both the IDHmut/non-co-deleted and IDHmut/co-deleted subgroups were significantly correlated with longer PFS (HR = 0.32; p = 0.003; HR = 0.13; p 〈 0.001) and OS (HR = 0.38; p = 0.013; HR = 0.21; p = 0.029) in the RT plus PCV arm, respectively. Conclusions: Our analyses suggest that both IDHmut/non-co-deleted and IDHmut/co-deleted subgroups received benefit from treatment with PCV although sample size is limited and analyses are post-hoc. Our results also support the notion that IDHwt high-risk LGG patients do not benefit from the addition of PCV to RT. Funding: U10CA180868, U10CA180822, and U24CA196067. Also, R01CA108633, R01CA169368, RC2CA148190, U10CA180850-01, BTFC, OSU-CCC (all to AC). Clinical trial information: NCT00003375.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2019.37.15_suppl.2002
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2019
detail.hit.zdb_id:
2005181-5
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