Tumor Volume Changes During and After Temozolomide Treatment for Newly Diagnosed Higher-Grade Glioma (III and IV).

Background: A standard post-concomitant radiochemotherapy involving adjuvant temozolomide (TMZ) was stopped after 6 cycles for high-grade gliomas (HGG). Several studies demonstrated that prolonged TMZ treatment increased survival for these patients.

Methods: This retrospective study aimed to compare changes in tumor volume during and after adjuvant TMZ treatment and overall survival (OS).

Results: There were 90 patients were administered adjuvant TMZ treatment. Comparing average tumor volume changes during TMZ treatment and after TMZ was stopped, a significant decrease in tumor volume was observed during TMZ treatment in the total patient population, the anaplastic astrocytoma (AA) group, and the glioblastoma multiforme (GBM) group (P ≤ 0.001, P = 0.042, and P = 0.005, respectively). Median overall survival was 78.4 weeks, which was significant regarding the surgical tumor resection rate (r = 0.241; P = 0.04) and total TMZ treatment cycles (r = 0.631; P ≤ 0.001).

Conclusions: During adjuvant TMZ treatment, tumor volume decreased significantly (P = 0.042, and P = 0.005, respectively) in patients with GBM and AA. Prolonged TMZ administration improved OS, without increased toxicity.