Microsatellite analyses of recurrence or second primary tumor in head and neck cancer

Background: In head and neck squamous cell carcinoma, distinguishing second primary tumors and recurrences may help to orient clin. decisions concerning therapy. Patients and Methods: A panel of eight microsatellite markers was used to analyze the loss of heterozygosity and genomic instability in a selected group of 32 patients experiencing a recurrence after having undergone surgery for oral or oropharyngeal carcinoma, in order to establish the clonality and origin of the recurrence. Results: Twenty-three patients showed genetic changes in primary and/or relapsing tumor DNA: clonally-related patterns were detected in six cases, whereas the different patterns between paired tumors indicated the presence of a second primary tumor in 17 cases. None of the markers was informative in nine cases. Conclusion: Our observations suggest that only a small proportion of patients have primary and secondary tumors developing from a single contiguous altered field (thus indicating a common clonal origin), whereas the metachronous tumor arises in unrelated fields in the majority of cases.