Prediction of recurrence by microsatellite analysis in head and neck cancer

We examined the possibility of using microsatellite alterations as markers to detect clonal tumor-derived cell populations in histopathologically nega tive surgical margins and cervical lymph nodes from head and neck cancer (H NC) patients. We used polymerase chain reaction (PCR)-based microsatellite analysis DNA to analyze primary tumors, paired surgical margins, and cervic al lymph nodes from 41 HNC patients. Samples were scored for alterations as defined by the presence of new alleles (shifts) or loss of heterozygosity (LOH) at each of 10 markers. We identified 25 (61%) patients with primary H NC who appeared to have had a complete resection on the basis of the histop athological assessment and who were informative regarding microsatellite al terations in tumor tissue. In 11 of these 25 (44%) cases, PCR analysis of s urgical margins showed the same microsatellite alterations as in the primar y tumors. In 7 of these 11 patients, the carcinoma recurred locally, as com pared with 1 out of 14 patients with negative margins (log rank test, P = 0 .0049). Conversely, we were unable to detect clonal neoplastic cells in his topathologically negative lymph nodes examined by molecular analysis. Cox r egression analysis showed that molecular positive margins were an independe nt prognostic factor (P = 0.04) for recurrence. This study demonstrates tha t microsatellite analysis may be a valuable tool for evaluating the risk of local recurrence. (C) 2000 Wiley-Liss, Inc.