Flow cytometric cellular DNA content and lymph-node metastasis in squamous-cell carcinoma of the oral cavity

This prospective DNA flow cytometric study on 386 primary squamous cell carcinomas of the oral cavity showed that only 18% of the patients with diploid primary tumors had lymph node metastasis on admission compared to 52% of those with aneuploid carcinomas. The aneuploid group without evidence of lymph node involvement at the time of primary tumor treatment carried a 3-fold increased risk for developing late metastasis (23%) compared with the diploid group (8%). The clinical manifestation of occult metastasis in patients with diploid carcinomas was delayed by about two years compared to the aneuploid group. These ploidy-specific differences of the metastatic behaviour held true even if stratified with respect to tumor stage, histological grade and tumor localization. These results provide substantial evidence that cells with gross DNA content aberrations have a significantly higher probability of successfully producing a metastatic colony than flow cytometrically diploid tumor cells. An excellent 5-year survival rate of 90% in the diploid NO group in contrast to 52% in aneuploid NO cases and an even worse survival rate of 21% in patients with lymph node involvement at presentation underline the clinical importance of these findings.