Association of CK19 mRNA detection of occult cancer cells in mediastinal lymph nodes in non-small cell lung carcinoma and high risk of early recurrence☆

This study was designed to screen occult cancer cells by CK19 mRNA detection using reverse transcriptase-polymerase chain reaction (RT-PCR) in mediastinal lymph nodes stations (MLNS) in non-small cell lung carcinoma (NSCLC). In 49 NSCLC patients free of mediastinal adenopathy on computed tomograph, 254 MLNS were evaluated by histopathology, immunohistochemistry (IHC) and RT-PCR. Of 225 non-tumoral MLNS on histopathology, 32 (14.2%) were positive by RT-PCR. IHC did not provide significant additional results. Seventeen patients were without mediastinal tumoral extension on histopathology and RT-PCR (Group 1), 16 were upgraded by RT-PCR (Group 2) and 16 pN2 on histopathology (Group 3). The two-year cancer-related death survival in Groups 1 (100%) and 2 (64.5%) was significantly different (P = 0.04). The relative risk of recurrence in Group 2 compared with Group 1, evaluated by the Cox model multivariate analysis, was 5.61 (P = 0.02). In conclusion, CK19 mRNA detected by RT-PCR in MLNS was significantly associated with an increased risk of rapid recurrence.