IDH mutation and MGMT promoter methylation are associated with the pseudoprogression and improved prognosis of glioblastoma multiforme patients who have undergone concurrent and adjuvant temozolomide-based chemoradiotherapy.

PURPOSE

This study aimed to investigate the potential association between IDH mutation and O-methyl-guanine methyl transferase (MGMT) gene promoter methylation and pseudoprogression disease (psPD) in glioblastoma multiforme (GBM) patients after concurrent temozolomide (TMZ)-based chemoradiotherapy.

METHODS

A total of 157 GBM patients who received concurrent TMZ-based chemoradiotherapy were included in this retrospective study. The association between psPD and a number of demographic and genetic factors, including IDH mutation and MGMT promoter methylation, were analyzed based on logistic regression, Cox regression, and multivariate analysis.

RESULTS

Of the 157 GBM patients, 145 (92.36%) patients, including 38 patients with psPD, 38 patients with early progression (ePD), and 69 patients with non-progression (non-PD), were followed up for six to 56 months. We identified a higher rate of MGMT promoter methylation and IDH1 mutation in psPD patients compared with ePD patients (P=0.002). In addition, MGMT promoter methylation and IDH1 mutation predicted a high probability of psPD development in GBM patients (P=0.001 and P<0.001, respectively). MGMT promoter methylation, IDH1 mutation, Karnofsky performance score (KPS) ≥70, and psPD were associated with a significantly longer overall survival of GBM patients (P=0.001, 0.001, 0.002, and P<0.001, respectively). Both of MGMT promoter methylation and IDH mutation had a cumulative effect on the OS of GBM patients. GBM patients with psPD (39.2±2.1months, P<0.001) had a longer median survival (MS) than GBM patients with ePD (11.9±1.1months) or with non-PD (24.4±2.4months).

CONCLUSION

MGMT promoter methylation and IDH1 mutation were associated with PsPD and predicted a longer median survival in GBM patients after TMZ-based chemoradiotherapy. Genetic analyses of the MGMT promoter and IDH1 may allow us to effectively treat GBM patients.