Effect of Whole-Brain and Intensity-Modulated Radiotherapy on Serum Levels of miR-21 and Prognosis for Lung Cancer Metastatic to the Brain.

BACKGROUND The goal of the present study was to explore the influence of whole-brain radiotherapy (WBRT) and intensity-modulated radiotherapy (IMRT) on serum levels of miR-21 and prognosis for lung cancer that has metastasized to the brain. MATERIAL AND METHODS Two hundred patients with lung cancer metastatic to the brain were randomized, half to the control group and half to the observation group. The observation group received WBRT and reduced-field IMRT (WBRT+RF-IMRT) and the control group received conventional-field IMRT (CF-IMRT). The total effective rate after treatment was determined. Serum levels of miR-21 were measured before and after radiotherapy with reverse transcriptase-polymerase chain reaction. In addition, tumor marker levels were measured with enzyme-linked immunosorbent assay. The relationship between miR-21 levels and tumor marker levels was assessed with a Pearson correlation coefficient test. Five-year survival was estimated with Kaplan-Meier curves. RESULTS The total effective rate was higher in the observation group (86%) than in the control group (69%). Lower levels of miR-21 and tumor markers were seen in the observation group. Moreover, miR-21 levels were positively correlated with levels of tumor necrosis factor-a, neuron-specific enolase, SCC-Ag, and carcinoembryonic antigen. Low levels of miR-21 were associated with longer overall survival in patients with lung cancer metastatic to the brain. CONCLUSIONS WBRT+RF-IMRT is superior to CF-IMRT for lung cancer metastatic to the brain. MiR-21 may be a marker for prediction of the efficacy of radiotherapy in this disease setting.