HYPOFRACTIONATED RADIOTHERAPY FOR GLIOBLASTOMA: A RETROSPECTIVE, SINGLE-CENTRE, 12-YEAR EXPERIENCE

Abstract AIMS Hypofractionated radiotherapy is used in older and less fit patients with glioblastoma; however, there have been no head-to-head trials comparing dose/fractionation schedules. Here, we present real-world data from patients treated at our centre with 30Gy in 6# or 40.05Gy in 15#. METHODS Retrospective analysis of patients treated between 2011 and 2023. Patients treated with 30Gy in 6# were split into 2 groups: before (30Gy-pre) and after (30Gy-post) 40.05Gy was used, following publication of the Perry et al. (2017) trial. Differences were assessed using the Kruskal-Wallis or Fisher’s test. Overall survival (OS) was calcu- lated using the Kaplan-Meier method. The Bonferroni correction resulted in a pre-determined significance level of p<0.016 for pair-wise log-rank tests. Univariate and multi-variate cox regression analyses were performed to identify prognostic factors. RESULTS 79 patients were included: 26 in the 30Gy-pre group, 24 in the 30Gy-post group and 29 in the 40.05Gy group. A higher proportion of patients in the 40.05Gy group commenced adjuvant chemotherapy; however, there were no other significant differences in baseline characteristics. Patients treated with 40.05Gy had the longest me- dian OS (9.8 months), followed by the 30Gy-pre group (8.7 months) and then 30Gy-post (6.9 months); however, pairwise comparisons demonstrated these differences were not statistically significant (40.05Gy vs. 30Gy-pre, p=0.16; 40.05Gy vs. 30Gy-post, p=0.03; 30Gy-pre vs. 30Gy-post, p=0.55). Univariate analysis demonstrated ra- diotherapy dose with 40.05Gy (HR: 0.56; 95% CI: 0.32–0.92), tumour methylation (HR 0.58; 95% CI: 0.34–0.96), adjuvant chemotherapy (HR 0.36; 95% CI: 0.21–0.59), and increased steroids following radiation (HR 2.93; 95% CI: 1.74–4.94) were associated with OS. Multivariate analysis demonstrated adjuvant chemotherapy (HR 0.27; 95% CI: 0.12–0.58) and increased steroids (HR 3.10; 95% CI: 1.74–4.94) were independent prognostic factors. CONCLUSION Our results demonstrate no significant differences in OS between hypofractionated schedules. Adjuvant chemotherapy was associated with improved OS. Multi-centre and prospective data are required to validate these findings.