Micrometastatic tumor detection in patients with head and neck cancer: A preliminary report

Objective To apply a new immunocytochemistry (ICC) assay to peripheral blood samples for micrometastatic circulating tumor cell detection in patients with head and neck squamous cell cancer (HNSCC). Design The ICC assay uses established monoclonal antibodies that bind to tumor-associated antigens combined with an enrichment system that uses positive selection with anti-human epithelial antigen (EpCAM antibody) to detect circulating tumor cells. Subjects Eighteen consecutive patients newly diagnosed as having HNSCC are described. Results Of the 18 patients, 8 (44%) demonstrated circulating tumor cells using the ICC assay. The numbers of patients positive for circulating tumor cells per stage are as follows: stage I, 1 of 1; stage II, 0 of 2; stage III, 2 of 5; stage IV, 5 of 6; and unknown stage, 0 of 4. The numbers of patients positive for circulating tumor cells per location are as follows: oral cavity, 1 of 2; oropharynx, 3 of 4; glottic area, 3 of 5; supraglottic area, 1 of 3; and unknown primary 0 of 4. Conclusions Circulating tumor cells were identified in almost half of the patients using the ICC assay. In a literature review, we were not able to identify previous reports of circulating tumor cell detection in patients with HNSCC from peripheral blood samples using ICC or identify any study that has attempted to quantify circulating tumor cell levels. Although the clinical implications of circulating tumor cells in micrometastatic tumor detection in patients with HNSCC are still unknown, they may be significant. Long-term follow-up may help elucidate the patients in whom conventional treatment may fail and, thus, those who may benefit from different treatment; it may also assist with the detection of recurrence with a simple blood collection.