The clinical characteristics and prognostic factors of multiple lesions in glioblastomas

Multiple glioblastomas (GBM) are the uncommon presentation of the disease. We aimed to identify the variables associated with the survival of patients with multiple GBMs according to the updated WHO classification.

We retrospectively reviewed 173 patients with newly diagnosed GBM between January 2003 and December 2018 and analyzed patients with multiple lesions at the time of diagnosis. The clinical, radiographic, and biomarkers were evaluated for descriptive analysis. The median overall survival and the Kaplan-Meier curves of the multiple GBMs were estimated. Furthermore, the Cox proportional hazard regression was the estimated hazard ratio for death according to various factors. Moreover, Schoenfeld's global test was performed for estimating assumptions.

Of these, 30 (17.3%) of all GBMs were multiple GBMs, and multifocal and multicentric GBMs were found in 27 (90%) and 3 (10%), respectively. The median survival of the multiple GBMs was significantly shorter than solitary GBM (6 vs. 12 months, p = 0.003). Using Cox proportional hazards regression, the independent prognostic factors of multiple GBMs were concomitant Temozolomide with radiotherapy, wild-type IDH1, methylated MGMT promoter methylation in univariate analysis. In multivariable analysis, concomitant Temozolomide (TMZ) with radiotherapy (RT) was the strongest predictor associated with prognosis in multiple GBMs (0.40, 95%CI 0.16-0.97).

Multiple lesions are uncommon findings in glioblastoma with poor prognostic features. Concomitant TMZ with RT was the strongest predictor of prognosis. In the future., IDH1 mutation and MGMT promoter methylation should be further explored as prognostic factors.