ESTRO meets Asia 2024 - Abstract Book

S95

Interdisciplinary – CNS

ESTRO meets Asia 2024

We conducted a retrospective review of patients with brain metastases who received SIB-WBRT (whole brain tissue 40 Gy/20 fractions, tumor tissue boosted to 56-60 Gy/20 fractions) and local irradiation (prescription dose range of 20-60 Gy/2-25 fractions, most commonly delivered as 30 Gy/5 fractions, with a BED range of 28-100.8 Gy) at Peking Union Medical College Hospital. Patient outcome measures included intracranial progression-free survival (iPFS) and overall survival (OS). Propensity score matching analysis was performed to compare the two retrospective cohorts. Kaplan-Meier method was utilized to depict and estimate overall survival (OS), intracranial progression-free survival (iPFS), occurrence of new intracranial lesions, and tumor control. Cox regression analysis was conducted to assess the association between relevant factors and outcomes.

Results:

After propensity score matching, 124 patients were enrolled in the SIB-WBRT and local irradiation of brain metastases groups, respectively, with a median time to local progression of 6.9 and 10.1 months and local control rates of 76.5% and 58.9% months versus 92.8% and 67.1% at 6 and 12 months after treatment in both SIB-WBRT and local irradiation of brain metastases groups. The median time to new intracranial foci was 8.63 and 6.2 months, with control rates of 75% and 55.1% versus 74.3% and 43.9% at 6 and 12 months. The median time to iPFS failure was 7.43 and 6.4 months, and the 6- and 12-month iPFS were 67.7% and 45.2% versus 72.6% and 34.6%. Patient age (95% CI: 1.021- 1.077, p =0.004), radiotherapy modality (95% CI: 1.01- 1.486, p =0.0389), tumor volume (GTVvolume) (95% CI: 1.266- 1.618, p <0.0001) and extracranial lesion control (95% CI: 1.191- 4.165, p =0.0122) were strongly associated with local control. No difference was observed in the incidence of new lesions between the two groups (48.39 % vs 41.94%, p =0.5885).

Conclusion:

Local irradiation brain metastases was better than SIB-WBRT for local control of brain metastases, but the incidence of new lesions did not differ between the two groups. Factors affecting local control may be age, GTVvolume, and extracranial lesion status.

Keywords: metastases,radiotherapy, lung cancer

References:

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