For patients with glioblastoma, short delays in the initiation of chemoradiotherapy after surgery did not appear to be linked to worse overall survival (OS) — yet initiation too soon after surgery was, found a study reported in Cancer.
The study included 30,414 patients from the National Cancer Database (NCDB) who had glioblastoma and underwent surgery followed by chemoradiotherapy between 2004 and 2013.
Receipt of chemoradiotherapy was categorized by week after surgery: 0 to 1 weeks, more than 1 to 2 weeks, more than 2 to 3 weeks, more than 3 to 4 weeks, more than 4 to 5 weeks, more than 5 to 6 weeks, more than 6 to 7 weeks, more than 7 to 8 weeks, and more than 8 weeks. Patients received chemoradiotherapy a median of 28 days (± 15.8 days) after surgery.
Patients were grouped according to the recursive partitioning analysis (RPA) classification system, derived from a pooled analysis of 4 Radiation Therapy Oncology Group (RTOG) clinical trials. Most patients were grouped as RPA class IV (68.6%) and the remaining as class III (17.3%) or class V (14.2%).
A multivariate analysis showed that receipt of chemoradiotherapy at any time interval beyond 5 weeks was not linked to worse OS, yet initiation of chemoradiotherapy within 1 week (hazard ratio [HR], 1.18; 95% CI, 1.02-1.35), more than 1 to 2 weeks (HR, 1.23; 95% CI, 1.16-1.31), and more than 2 to 3 weeks after surgery (HR, 1.11; 95% CI, 1.06-1.15) were linked to worse OS.
An additional multivariate analysis indicated that receipt of chemoradiotherapy within 3 weeks after surgery was consistently associated with worse OS across RPA classes III, IV, and V, “suggesting that it cannot be attributed entirely to patients with a poor prognosis,” the study authors wrote.
“This study is not advocating for delaying treatment as a new standard of care,” the study authors cautioned. These data, they explained, “favor avoiding the initiation of adjuvant therapy within the first 3 weeks after surgery if possible and could be used to reassure patients and providers in the scenario of unexpected delays.”
Press RH, Shafer SL, Jiang R, et al. Optimal timing of chemoradiotherapy after surgical resection of glioblastoma: Stratification by validated prognostic classification [published online April 28, 2020]. Cancer. doi: 10.1002/cncr.32797