Dataset Information

High-dose radiotherapy in newly diagnosed low-grade gliomas with nonmethylated O(6)-methylguanine-DNA methyltransferase.

ABSTRACT:

Background

Patients with low-grade gliomas (LGGs) harboring O⁶-methylguanine-DNA methyltransferase promoter nonmethylation (MGMT-non-pM) have a particularly short survival and are great resistance to chemotherapy. The objective of this study was to assess the efficacy of high-dose radiotherapy (RT) for LGGs with MGMT-non-pM.

Methods

268 patients with newly diagnosed adult supratentorial LGGs from the multicenter Chinese Glioma Cooperative Group (CGCG) received postoperative RT during 2005-2018. MGMT promoter methylation analysis was conducted by pyrosequencing in all patients. Univariate and multivariate analysis were performed using the Cox regression to determine the prognostic factors for overall survival (OS) and progression-free survival (PFS). RT dose-response on MGMT status defined subtypes was analyzed.

Results

On univariate analysis, the following were statistically significant favorable factors for both PFS and OS: oligodendrogliomas(p = 0.002 and p = 0.005), high-dose RT (> 54 Gy) (p = 0.021 and p = 0.029) and 1p/19q codeletion (p < 0.001 and p = 0.001). On multivariate analysis, RT dose (> 54 Gy vs. ≤ 54 Gy) and IDH mutation were independently prognostic markers for OS (HR, 0.47; 95%CI, 0.22-0.98; p = 0.045; and HR, 0.44; 95%CI, 0.21-0.96; p = 0.038, respectively) and PFS (HR, 0.48; 95%CI, 0.26-0.90; p = 0.022; and HR, 0.51; 95%CI, 0.26-0.98; p = 0.044, respectively). High-dose RT was associated with longer OS (HR, 0.56; 95%CI, 0.32-0.96; p = 0.036) and PFS (HR, 0.58; 95%CI, 0.35-0.96; p = 0.033) than low-dose RT in MGMT-non-pM subtype. In contrast, no significant difference in either OS (p = 0.240) or PFS (p = 0.395) was observed with high-dose RT in the MGMT-pM subtype.

Conclusions

High-dose RT (> 54 Gy) is an independently protective factor for LGGs and is associated with improved survival in patients with MGMT-non-pM.

SUBMITTER: Liu Y

PROVIDER: S-EPMC8375106 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundThe radiation dose for patients with low-grade gliomas (LGGs) is controversial. The objective of this study was to investigate the impact of the radiation dose on survival for patients with LGGs and especially for molecularly defined subgroups.MethodsThree hundred fifty-one patients with newly diagnosed LGGs from the multicenter Chinese Glioma Cooperative Group received postoperative radiotherapy (RT) in 2005-2018. The RT dose, as a continuous variable, was entered into a Cox regression model using penalized spline regression to allow for a nonlinear relationship between the RT dose and overall survival (OS) or progression-free survival (PFS). Inverse probability of treatment weighting (IPTW)-adjusted propensity scores were used to correct for potential confounders. Dose effects on survival within IDH mutation and 1p/19q codeletion defined subgroups were analyzed.ResultsThe risk of mortality and disease progression decreased sharply until 54 Gy. High-dose RT (≥54 Gy) was associated with significantly better 5-year OS (81.7% vs 64.0%; hazard ratio [HR], 0.33; P < .001) and PFS (77.4% vs 54.5%; HR, 0.46; P < .001) than low-dose RT (<54 Gy). IPTW correction confirmed the associations (HR for OS, 0.44; P = .001; HR for PFS, 0.48; P = .003). High-dose RT was associated with longer PFS (HR, 0.25; P = .002; HR, 0.21; P = .039) and OS (HR, 0.27; P = .006; HR, 0.07; P = .017) in IDH-mutant/1p/19q noncodeleted and IDH wild-type subgroups, respectively. No significant difference in survival was observed with high-dose RT in the IDH-mutant/1p/19q codeleted subgroup.ConclusionsHigh-dose RT (≥54 Gy) was effective in LGGs. Patients with an IDH mutation/1p/19q noncodeletion or IDH wild-type may need to be considered for high-dose RT.Lay summaryThe radiotherapy dose-response was observed in patients with low-grade gliomas, and high-dose radiotherapy (≥54 Gy) was associated with improved survival. Patients with an IDH mutation/1p/19q noncodeletion or wild-type IDH may have improved survival with the administration of high-dose radiotherapy.