WHO dunnit.

Top Line: RTOG 9802 demonstrated that adding adjuvant procarbazine, lomustine and vincristine (PCV) after radiation for high-risk, low-grade glioma dramatically improved median overall survival from 7.8 to 13.3 years.

The Study: While IDH mutation status has been analyzed, this report gives a much more comprehensive genomic look at treatment outcomes according to WHO prognostic class. Close to half (46%, n=106) had tissue available for genomic analysis that specifically looked for mutations in IDH1-R132H, non-canonical IDH 1/2, ATRX, CIC, FUBP1, and TERT promoter, as well as the better known 1p19q codeletion and MGMT promoter methylation. This also allowed for classification into three WHO prognostic classes: IDHmut/codel (35%), IDHmut/non-codel (41%), and IDHwt (24%). From a prognostic standpoint, median overall / progression-free survival according to WHO class was 14 / 10 years for IDHmut/codel, 7 / 4 years for IDHmut/non-codel, and 2 / <1 years for IDHwt. The first two classes were also predictive of a benefit from PCV, while IDHwt patients saw no improvement with the addition of adjuvant PCV.

TBL: IDH-mutation and 1q19q co-deletion status are prognostic and predictive of treatment outcome with radiation and adjuvant PCV for high-risk, low-grade glioma. | Bell, J Clin Oncol 2020