Neoadjuvant cisplatin plus temozolomide versus standard treatment in patients with unresectable glioblastoma or anaplastic astrocytoma: a differential effect of MGMT methylation

Patients with unresectable glioblastoma or anaplastic astrocytoma have a dismal prognosis. The role of neoadjuvant chemotherapy prior to irradiation in these patients has been studied primarily in non-randomized studies. We have compared the effect of neoadjuvant chemotherapy plus radiotherapy versus concomitant radiotherapy plus temozolomide in a retrospective analysis of two consecutive series of patients in whom surgery consisted of biopsy only. From 2003 to 2005, 23 patients received two cycles of temozolomide plus cisplatin followed by radiotherapy (Cohort 1), and from 2006 to 2010, 23 additional patients received concomitant radiotherapy and temozolomide followed by adjuvant temozolomide (Cohort 2). In Cohort 1, 91.3 % of patients received all planned chemotherapy cycles. Progression-free and overall survival were 3.3 and 8.5 months, respectively. In Cohort 2, progression-free and overall survival were 5.1 and 11.2 months, respectively. No differences between the two groups were observed in rate of completion of radiotherapy, progression-free or overall survival. MGMT methylation was assessed in 91.3 % of patients. In Cohort 1, patients without MGMT methylation showed a trend towards shorter progression-free survival (P = 0.09), while in Cohort 2, patients without MGMT methylation had longer progression-free survival (P = 0.04). In the overall patient population, neoadjuvant temozolomide plus cisplatin had neither a positive nor negative influence on outcome. However, our findings indicate that patients with methylated MGMT may derive greater benefit from neoadjuvant temozolomide than those with unmethylated MGMT.