Effects of Radiotherapy Alone Versus Concomitant Radiotherapy With Temozolomide Chemotherapy on the Outcome of IDH-wildtype Glioblastoma Patients.

Background: Isocitrate dehydrogenase [IDH]-wildtype glioblastoma is an aggressive brain cancer associated with high recurrence and poor overall survival.

Aim: Our study aims to explore the prognostic effects of radiotherapy [RT] alone versus concomitant RT with temozolomide [TMZ].

Methods: A multicentre retrospective study included a cohort of 244 patients diagnosed with IDH-wildtype glioblastoma, and it was analysed from 2013 to 2020. All patients underwent complete surgical resection of the tumour followed by standard postsurgical therapies, including RT alone [group A] or concomitant RT with TMZ chemotherapy [group B]. Intra-statistical cohort data analysis was performed.

Results: The mean age of the patients was 53.9 years [SD 16.3 years], with 87 [35.7%] females and 157 [64.3%] males. Group "A" patient [n = 67, 27.5%] received RT alone, and group "B" patient [n = 177, 72.5%] received concomitant RT with TMZ chemotherapy. All patients' mean progression-free survival [PFS] was 391.8 days (13.1 months). There was a statistically significant difference in PFS between the two treatment groups [P value<0.0001]. The hazard ratio [HR] for PFS in group "b" compared with group "a" was 0.48 [95% CI: 0.36-0.64, P < 0.001] in the univariable analysis, indicating a significant benefit of the combined treatment. This benefit was maintained in the multivariable analysis with an HR of 0.50 [95% CI: 0.37-0.67, P < 0.001]. Age was found to be a significant factor in PFS, with each additional year of age increasing HR by 2% in the univariable analysis [HR: 1.02, 95% CI: 1.01-1.03, P < 0.001] and the multivariable analysis (HR of 1.01 [95% CI: 1.01-1.02, P < 0.001)].

Conclusions: Concomitant RT with TMZ chemotherapy significantly increased PFS beyond that observed from isolated RT in patients with IDH-wildtype glioblastoma.