Focal conformal fractionated radiotherapy vs. radiosurgery for lung cancer patients with limited brain metastases.

Background: For lung cancer (LC) patients with limited brain metastases (LBM), radiosurgery (RS) was the current preferred strategy. We aimed to report our experience regarding an alternative strategy (focal conformal fractionated radiotherapy, FCFRT) for these patients in this cohort study.

Methods: We identified LC patients with LBM treated with either FCFRT or RS within 2016-2019 without prior brain local treatment via in-house databases. The characteristics of patients, disease, treatment, and outcome were retrospectively obtained via chart review and peer review. The 1st day of FCFRT or RS was the index date. Overall survival (OS) was calculated from the index date to the last date of contact or death via the Kaplan-Meier method. Log-rank test was used in univariate analyses (UVA) whereas Cox regression method was used in the multivariate analyses (MVA). The incidence of local progression (LP) or distal brain metastases (DBM) was estimated by the competing risk approach with death as the competing risk.

Results: We identified 23 eligible patients. The median dose/fractionation for FCFRT was 36 Gy/10 fractions. The median dose for RS was 20 Gy. The Lung-molGPA prognostic groups' distribution for these two groups was not statistically different. After a median follow-up of 8 months (range, 1-38 months), the OS was not statistically different in UVA [P value 0.9]. The adjusted hazard ratio of death was 0.96 when FCFRT was compared to RS in MVA (95% CI, 0.21-5.22). There was also no statistical significant difference in LP (P value 0.79) or DBM (P value 0.88).

Conclusions: For LC patients with LBM, the OS was not statistically different for definitive FCFRT or RS. There was also no statistical difference in LP or DBM. Further studies should be considered to clarify the indication of FCFRT.