A Systematic Review of Risk Factors for Brain Metastases and Value of Prophylactic Cranial Irradiation in Non-Small Cell Lung Cancer

Background: The incidence of brain metastases (BM) varies in patients with non-small cell lung cancer(NSCLC), calls into question the value of prophylactic cranial irradiation (PCI). It is possible that clinicopathologiccharacteristics are associated with the development of BM, but these have yet to be identified in detail. Thus,we conducted the present meta-analysis on risk factors for BM and the value of PCI in patients with NSCLC.
Methods: Eligible data were extracted and the risk factors for BM and the value of PCI in patients with NSCLCwere analyzed by calculating the pooled odds ratio (OR). Heterogeneity was detected using Q and I-squaredstatistics, and publication bias was tested by funnel plots and Egger’s test.
Results: Six randomized controlledtrials with a focus on the value of PCI and 13 eligible studies with a focus on risk factors for BM were included.PCI significantly reduced the incidence of BM in patients with NSCLC (p=0.000, pooled OR=0.34, 95% confidenceinterval = 0.37-0.59). Compared with non-squamous cell carcinoma, squamous cell carcinoma was associatedwith a low incidence of BM in patients with NSCLC (p=0.000, pooled OR=0.47, 95% confidence interval =0.34-0.65). The funnel plot and Egger’s test suggested that there was no publication bias in the current meta-analysis.
Conclusions: This meta-analysis provides statistical evidence that compared with non-squamous cell carcinoma,squamous cell carcinoma can be used as a predictor for BM in patients with NSCLC, and PCI might reduce theincidence of BM in patients with NSCLC, but does not provide a survival benefit.