BACKGROUNDBrain metastasis has become one of the most important factors of the failure of treatment of locally advanced non-small cell lung cancer (LANSCLC). There is no conclusion whether NSCLC patients should receive prophylactic cranial irradiation (PCI) or not. The aim of this study is to analyze the risk factors of brain metastasis of LANSCLC after surgery to find out the sign of PCI for LANSCLC.

METHODSA total of 223 patients with stage III NSCLC who received surgical resection were retrospectively analyzed. The risk factors of brain metastasis were determined to set up a mathematic model for brain metastasis.

RESULTSThe median survival time after surgery was 28.0 months. The 1-, 2- and 3-year survival rate was 84.3%, 56.9% and 44.8% respectively. The incidence of brain metastasis was 38.1% (85/223). Patients with extensive mediastinal lymph node metastasis, more node metastasis and non-squamous carcinoma showed significantly higher incidence of brain metastasis than those with limited mediastinal lymph node metastasis, fewer positive mediastinal lymph nodes and squamous carcinoma (P=0.000, P=0.000, P=0.013). The mathematic model of brain metastasis was: logit(P)=8.215-0.903×NPN-0.872×RT-0.714×HG-1.893×LE-0.948×HS-1.034×PC (NPN=No. of positive nodes, RT=resection type, HG=histology, LE=location and extent of mediastinal lymph node metastasis, HS=histologic stage, PC=postoperative chemotherapy). P≥0.44 meant high risk for brain metastasis.

CONCLUSIONSHigh risk factors of brain metastasis in LANSCLC patients after complete resection of the cancer include non-squamous carcinoma, extensive and more mediastinal lymph node metastasis. P≥0.44 may be considered a sign of PCI in clinical trial.