# Surgery to chemoradiotherapy time may not impact outcomes in glioblastoma patients treated with modern techniques: a single-institution study

## TL;DR

This study found that delaying chemoradiotherapy after surgery for glioblastoma by more than 42 days does not significantly affect patient survival outcomes.

## Contribution

The study provides new evidence that modern treatment techniques may reduce the impact of treatment delays in glioblastoma.

## Key findings

- Delays in chemoradiotherapy beyond 42 days did not significantly affect overall or progression-free survival.
- ECOG performance score 1 and subtotal resection were associated with worse outcomes.
- No significant survival differences were found when analyzing the time to treatment by extent of surgery.

## Abstract

Surgery followed by chemoradiotherapy (CRT) with temozolomide is the standard
treatment for glioblastoma patients. But, the time between surgery and CRT
is still a controversial issue. This study investigated the impact of delay
in CRT after surgery on overall (OS) and progression-free survival
(PFS).

Patients aged ≥ 18 years with IDH-wild type glioblastoma, who received 60 Gy
concomitant CRT with temozolomide were included in the study. Exclusion
criteria include patients who underwent biopsy only, had an Eastern
Cooperative Oncology Group (ECOG) performance status > 1, or presented
with multicentric tumors. The interval between surgery and CRT was
categorized according to 42 days, and delays after this point were defined
as delayed treatment initiation. Statistical analyses included Kaplan-Meier
survival analysis and Cox regression models.

The median OS for the regular and delayed groups was 18 and 19 months, and
the PFS was 11.8 and 14.6 months, respectively. Delayed patients showed
better PFS, but no statistically significant difference was found between
the groups in terms of OS and PFS (p = 0.149, p = 0.076). In multivariate
analysis, ECOG performance score 1 and subtotal resection were associated
with poor prognosis for both OS and PFS (for OS p = 0.031, p < 0.001; for
PFS p = 0.038, p = 0.029). When the time from surgery to CRT was analyzed
according to the extent of surgery, no significant difference was observed
in OS and PFS (p = 0.068, P = 0.057).

Our findings showed that delays of more than 42 days in adjuvant CRT did not
affect OS or PFS. However, further studies are needed to evaluate the
effects of delayed adjuvant therapy in patients with subtotal resection.