Clinical relevance of circulating tumour cells in the bone marrow of patients with SCCHN

Background: Clinical outcome of patients with head and neck
squamous cell carcinoma (SCCHN) depends on several risk factors
like the presence of locoregional lymph node or distant metastases,
stage, localisation and histologic differentiation of the tumour.
Circulating tumour cells in the bone marrow indicate a poor
prognosis for patients with various kinds of malignoma. The present
study examines the clinical relevance of occult tumour cells in
patients suffering from SCCHN. Patients and Methods: Bone marrow
aspirates of 176 patients suffering from SCCHN were obtained prior
to surgery and stained for the presence of disseminated tumour
cells. Antibodies for cytokeratin 19 were used for
immunohistochemical detection with APAAP on cytospin slides. Within
a clinical follow-up protocol over a period of 60 months, the
prognostic relevance of several clinicopathological parameters and
occult tumour cells was evaluated. Results: Single CK19-expressing
tumour cells could be detected in the bone marrow of 30.7% of the
patients. There is a significant correlation between occult tumour
cells in the bone marrow and relapse. Uni- and multivariate
analysis of all clinical data showed the metastases in the
locoregional lymph system and detection of disseminated tumour
cells in the bone marrow to be statistically highly significant for
clinical prognosis. Conclusion: The detection of minimal residual
disease underlines the understanding of SCCHN as a systemic
disease. Further examination of such cells will lead to a better
understanding of the tumour biology, as well as to improvement of
diagnostic and therapeutic strategies.