Application of magnetic resonance diffusion-weighted imaging combined with serum tumor markers in brain metastases of small cell lung cancer / 肿瘤研究与临床

ABSTRACT

Objective To investigate the value of magnetic resonance diffusion-weighted imaging (DWI) in combination with peripheral serum tumor markers in the diagnosis and therapeutic evaluation of small cell lung cancer (SCLC) brain metastases.Methods Retrospective analysis of 368 SCLC cases diagnosed by histopathology or cytology from February 2009 to February 2012 in Shanxi Provincial Cancer Hospital was made.All patients underwent pathological examination of progastrin-releasing peptide (ProGRP),neuron-specific enolase (NSE) and brain DWI,and measured the apparent diffusion coefficient (ADC) of DWI sequences of brain metastases.The difference between the positive rates of ProGRP and NSE in patients with or without brain metastases was compared by the X2 test,and the diagnostic efficiency of ProGRP,NSE,DWI and combined detection for brain metastases were analyzed.The Kruskal-Wallis H test was used to compare the changes of ADC value,ProGRP and NSE before and after brain irradiation therapy in brain metastases of SCLC.Pearson correlation analysis was made to evaluate the correlation between the changes of ADC value and the levels of ProGRP and NSE in SCLC patients with brain metastases before and after treatment.Results The median expression of serum ProGRP in 169 SCLC patients was 2 664.7 pg/ml (98.4-4 876.8 pg/ml),with a positive rate of 98.2 ％ (166/169).The median expression of NSE was 41.9 μg/L (9.4-264.3 μg/L),with a positive rate of 70.4 ％ (119/169).The median expression of serum ProGRP level was 514.3 pg/ml (3.9-2 899.3 pg/ml) in 199 SCLC patients without brain metastasis,the positive rate was 89.4 ％ (178/199).The median expression of NSE was 40.4 μg/L (0.3-176.1 μ,g/L),with a positive rate of 64.8 ％ (129/199).The difference of ProGRP level between the two groups was statistically significant (u =121.47,P ＜ 0.001),but there was no significant difference in NSE level (u =1.35,P =0.12).The sensitivities of ProGRP,NSE,DWI,ProGRP+DWI and NSE+DWI were 68.4 ％,41.2 ％,66.7 ％,92.2 ％,and 82.4 ％,and the specificities were 52.9 ％,35.3 ％,76.5 ％,94.1％,and 88.2 ％.The sensitivity and specificity of ProGRP+DWI and NSE+DWI were higher than those of single test,and the differences were statistically significant (all P ＜ 0.001).One hundred and fifty-six SCLC patients with brain metastases were treated with whole brain radiotherapy.Pearson correlation analysis showed that ADC values were negatively correlated with ProGRP and NSE levels (r =-0.945,P ＜ 0.001;r =-0.995,P ＜ 0.001).Conclusion DWI combined with ProGRP and NSE can provide objective evidence and clinical guidance for the diagnosis of SCLC brain metastases and the evaluation of whole brain radiotherapy.