Background & objective: Regional lymph node micrometastasis, which can not be found by routine pathologic examination, may be detected by immunohistochemistry after radical operation of tumors. This study was to investigate regional lymph node micrometastasis in non-small cell lung cancer (NSCLC) and its impact on prognosis.
Methods: The expressions of cytokeratin (CK) in 684 specimens from 78 stage pT1-2N0M0 NSCLC patients, treated from Jan. 1996 to Dec. 2003, were detected by EnVision method using anti-CK antibody AE1/AE3. The correlation of CK expression to prognosis was analyzed.
Results: The overall detection rate of CK was 26.9%û the detection rates were 5.9% in stage p-IA patients and 32.8% in stage p-IB patients. The 1-, 3-, 5-, and 8-year survival rates were significantly higher in non-micrometastasis group than in micrometastasis group (90.80% vs. 60.00%, 69.70% vs. 48.48%, 55.76% vs. 29.09%, and 37.17% vs. 0, P=0.008)û the median survival time were 87 months and 23 months, respectively. CK and KPS score were independent prognostic factors of NSCLC (P=0.014, P<0.001). Compared with surgery alone, surgery plus postoperative radiochemotherapy prolonged survival, but the difference was not significant (P=0.063).
Conclusions: The detection rate of lymph node micrometastases may be increased with the progression of NSCLC. Micrometastasis is an independent prognostic factor of NSCLC.