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Updated: Jul 24, 2026
Combination Radiotherapy in an Orthotopic Mouse Brain Tumor Model
Published on: March 6, 2012
A retrospective propensity-matched study comparing whole-brain radiotherapy with simultaneous integrated boost to
Zheqing Liu1, Xiaojing Du1, Meiling Deng1
1Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Sun Yat-Sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, 510060, P.R. China.
Background:
The effectiveness of whole brain radiation therapy with simultaneous integrated boost (WBRT-SIB) in comparison to whole brain radiation therapy alone (WBRT-alone) is yet unknown, despite the fact that its use in clinic is growing. To investigate the variations in intracranial control and overall survival (OS) between the two approaches, we conducted a matching comparison for patients with brain metastases (BM).
Method:
From January 1, 2015, to December 31, 2019, a total of 245 BM patients were eligible for inclusion, including 154 patients who received WBRT-alone (30 Gy/10 fractions) and 91 patients who received WBRT-SIB (40-50 Gy/10 fractions). 1:1 propensity score matching was used to select the patients with balanced baseline characteristics. The intracranial control and OS condition were analyzed using Kaplan-Meier method, Log-rank test, and Cox proportional hazard regression model.
Results:
138 patients were matched into the WBRT-SIB group and the WBRT-alone group. Of these, 113 (81.9%) patients had BM originating from the lungs, and 124 (89.9%) patients had more than 3 intracranial lesions. After the initiation of radiotherapy, the WBRT-SIB group and the WBRT-alone group had respective 2-year intracranial progression-free survival (iPFS), local progression-free survival (iLPFS), and distant progression-free survival (iDPFS) of 46.2% and 24.5% (p = 0.017), 49.4% and 29.8% (p = 0.033), and 68.6% and 54.4% (p = 0.040). There was no significant difference in OS (22.2 vs. 19.0 months, p = 0.768). However, in the exploratory subgroup analysis of infratentorial with/without supratentorial metastases (n = 96), the WBRT-SIB group showed a significantly better OS than the WBRT-alone group (24.6 vs.17.2 months, p = 0.040). Furthermore, the Cox proportional hazard model of this subgroup revealed that WBRT-SIB (p = 0.039) and systemic therapy after radiotherapy (p = 0.002) were independent prognostic factors for OS. There was no difference in the incidence of grade 3-4 acute brain radiation reactions between the two groups (24.6% vs. 17.4%, p = 0.290).
Conclusion:
WBRT-SIB is a promising strategy for patients with BM. Compared to WBRT alone, WBRT-SIB can significantly prolong the intracranial PFS (including local and distant PFS). Additionally, while WBRT-SIB did not improve OS in the entire cohort, the OS benefit for patients with BM accompanied by infratentorial involvement warrants further exploration.
