Glioblastoma multiforme (GBM) is the most common, malignant primary brain tumor. Surgical resection followed by concurrent Chemoradiation (CCRT) and adjuvant chemotherapy is the standard treatment at this time. Unlike other tumors, the impact of the time to initiation of CCRT on outcome remains unclear. The aim of this analysis was to investigate the impact of time to initiation of CCRT on outcome in patients with GBM treated at King Fahad Medical City (KFMC), Saudi Arabia.
All adult patients treated with CCRT at KFMC from January 2008 until June 2016 were included. A data collection form was developed to collect patient demographics, pathology, radiotherapy and chemotherapy details, progression and survival outcomes. The interval to initiation of CCRT was determined from the time of surgical intervention. The impact of the time to initiation of CCRT on overall (OS) and progression-free (PFS) survival was evaluated by univariate Log-rank tests and multivariate Cox-regression analysis.
In this analysis, 100 patients treated with CCRT were included. Median age was 49 (18-81). 72% of included patients were male, and 89% underwent resection. The majority of patients, 79% received adjuvant Temozolomide (TMZ) with a median of 4 cycles. The median of time to initiation of CCRT was 5.1 weeks (1.4 to 12.8) with 33% of patient were started on CCRT beyond six weeks of surgery. In univariate and multivariate analyses, time to initiation of CCRT have no significant impact on either PFS (univariate, p = 0.81, multivariate, p = 0.96) or OS (univariate, p = 0.44, multivariate, p = 0.43). On multivariate analysis, the better survival rate was seen in patients received adjuvant TMZ (P = 0.001) and worse survival rates were associated with ECOG >2 (P = 0.009), the presence of comorbidities (P = 0.04) and residual disease (P = 0.004).
In this single-center retrospective study, no significant impact of the time to initiation of CCRT was demonstrated on the outcome of GBM patients. Prospective studies are needed to define the optimal timing of CCRT after surgical resection in GBM.
Ethical Committee- King Fahad Medical City -Riyadh -Saudi Arabia