OBJECTIVE
To investigate the effect of two fractionation regimens on survival in patients with Grade IV gliomas depending on rapid early progression (REP).
MATERIAL AND METHODS
Fractionation with prescribed doses of 2 and 3 Gy was alternately used in 140 patients with morphologically confirmed Grade IV glioma using a pairwise modeling strategy.
RESULTS
REP was diagnosed in 60 (42.9%) out of 140 patients with Grade IV gliomas and 55 (45.5%) out of 121 patients with glioblastomas. Fatal outcome was observed in 111 (79.3%) patients, 99 (70.7%) ones died from progression of glioma. In case of no REP, the median overall survival as of December 2023 was 32.20 (95% CI 25.7-38.7) months, with REP — only 16.03 (95% CI 13.5-18.6) months (p<0.0001). Median survival was slightly lower in patients with glioblastoma — 28.2 and 16.5 months, respectively (p<0.0001).
In patients with Grade IV gliomas and no REP, 3 Gy (n=40) fractionation regimen was followed by median overall survival 44.98 (95% Cl 15.3-74.6) months, 2 Gy (n=40) — 20.99 (95% CI 9.2-32.7) months (p=0.027). In case of glioblastoma, differences between fractionation regimes lose significance — medians 33.7 and 19.7 months, respectively (p=0.081). According to multivariate analysis, 3 Gy fractionation regimen is more effective than standard radiotherapy (p=0.009) in patients without REP, while significance of isoeffective doses <59.5Gy≥ is slightly lower (p=0.020). Radiotherapy on the background of temozolomide is equally important (p=0.007).
In patients with grade 4 gliomas and REP, 3 Gy (n=30) fractionation regimen was followed by median overall survival 17.18 (95% CI 14.2-20.2) months, 2 Gy (n=30) — 12.88 (95% CI 5.4-20.3) months (p=0.849). In case of glioblastoma, Cox model classification matrix looks as follows: fractionation variant (p=0.423), isoeffective dose <59.5Gy≥ (p<0.0001), temozolomide during radiotherapy (p=0.701), functional status (p=0.485).
CONCLUSION
In patients with Grade IV gliomas and no REP, 3 Gy fractionation regimen has significant advantages over standard radiotherapy regarding overall survival. In case of more aggressive course of tumor (REP), higher single dose does not improve treatment outcomes. Isoeffective dose ≥59.5Gy is of great importance.
