Gene diagnosis and prognostic significance of lymph node micrometastasis after complete resection of histologically node-negative non-small cell lung cancer

Background The purpose of the present study was to investigate the prevalence of lymph node micrometastasis (LNMM) based on the detection of MUC1 mRNA, and assess the impact of these micrometastases on prognosis after resection of pathologic N0 (pN0) non-small cell lung cancer (NSCLC). Methods The subjects were 89 patients who underwent complete resection of pN0 NSCLC at our department between January 2000 and January 2002. All lymph nodes (402 stations) obtained from these patients were re-evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) to detect MUC1 mRNA. The diagnosis of LNMM was based on the detection of MUC1 mRNA. The Kaplan-Meier method was used to calculate the survival rate, and Cox regression multivariate analysis was performed to determine independent prognostic factors. Results Micrometastases were detected in 36 lymph node stations (9.0%) from 21 patients (23.6%). The TNM staging of these 21 patients was upregulated from stage IA-IIB to stage IIIA. The 5-year survival rate of patients with LNMM was significantly lower than that of patients without LNMM (23.8% versus 44.1%; p < 0.05). The results of multivariate analysis confirmed that T status, histology, and LNMM were independent prognostic factors. Conclusions The prevalence of LNMM in patients with pN0 NSCLC was 23.6% (21/89). T status, histology, and LNMM were independent prognostic factors.