Clinical evaluation of a new molecular method for detection of micrometastases in head and neck squamous cell carcinoma.

OBJECTIVE To better detect occult cervical metastases. DESIGN RNA from 153 cervical lymph nodes was analyzed for the presence of squamous cell carcinoma using quantitative cytokeratin (CK) 14 real-time reverse transcription polymerase chain reaction (RT-PCR). Detection of CK RNA in pathologically negative nodes was further analyzed by semi-step sectioning and CK immunohistochemistry. Subjects Thirteen consecutive patients with head and neck squamons cell carcinoma (HNSCC) presenting to the Department of Otolaryngology/Head and Neck Surgery of the University of North Carolina at Chapel Hill for neck dissection. RESULTS Cytokeratin detection was deemed nonspecific if expressed at fewer than 50 molecules of CK 14 RNA per nanogram total RNA. Of 35 HNSCCs, 33 expressed CK 14 RNA, and 15 lymph nodes with routine pathologically positive metastasis were also positive for CK 14 RNA. Four lymph nodes that were pathologically negative nodes were positive for CK 14 RT-PCR, with 2 containing metastases detected by semi-step sectioning. CONCLUSIONS Cytokeratin 14 RT-PCR is very sensitive for detecting micrometastasis in lymph nodes that are negative by routine pathological examination, with a relatively high false-positive rate. Quantitative CK 14 RT-PCR could be used to identify nodes negative for tumor by standard pathological analysis that should be examined by step sectioning and CK immunohistochemistry. Identification of micrometastases in patients with HNSCC will allow for appropriate and aggressive treatment of patients with metastatic disease.