The significance of DNA flow cytometry in predicting survival and delayed clinical manifestation of occult lymph node metastasis to the untreated neck in patients with oral squamous cell carcinoma

A total number of 116 clinically neck-negative patients with squamous cell carcinoma of the oral cavity who underwent radical primary tumour surgery w ithout simultaneous neck treatment mere entered into this prospective study . The 5 year overall survival rate was 87% :for patients with flow cytometr ically diploid tumours and 58% for the aneuploid group (P<0.05), By multiva riate survival analysis, tumour stage (P<0.05) and DNA ploidy (P<0.05) mere significantly associated with the outcome. The cumulative 3 gear rate of d elayed clinical manifestation of lymphnode metastasis to the previously unt reated neck mas 12.6% for patients with flow cytometrically diploid rumours and 41.3% for the aneuploid group (P<0.01), By multivariate analysis, the DNA ploidy status of the primary tumour was the only factor among tumour st age, localization and degree of histological differentiation predictive of occult metastasis development (P<0.05), Also, patients with T-1 tumours who frequently are not considered to benefit from elective neck dissection wer e at high risk of subclinical lymphnode involvement if the primary tumours were aneuploid (47%), whereas only 10% of the diploid T-1 sample showed occ ult neck disease. Particularly in patients with less extensive oral carcino mas, DNA aneuploidy is therefore an important decisive factor in elective n eck dissection.