The prediction of lymph node metastases from oral squamous carcinoma.

In an attempt to predict which cases of oral and oropharyngeal squamous carcinoma are likely to metastasize to regional lymph nodes a series of 898 cases was grouped according to site, size, grade of histological differentiation, and presence or absence of histologically confirmed regional lymph node metastases. The results were analysed by a logistic multiple regression analysis. They showed that the sites may be divided into three clusters, Cluster 1 consists of tumors of lip, floor of mouth, cheek mucosa, hard palate, and gingiva. These are not significantly different as regards metastasis rate. Cluster 2 consists of tumors of the anterior two-thirds of tongue and has a higher tendency to metastasis than those in Cluster 1. Lesions of the posterior third of tongue and oropharynx form Cluster 3 which exhibits the greatest tendency to metastasis. Sizes of primary lesions are clustered in groups of lesions less than 3 cm, those 3 to less than 4 cm, and those 4 cm or larger, in ascending tendency to metastasis. Well-differentiated and moderately differentiated tumors are not significantly different in their tendency to metastasize and may be reduced to a single cluster, whereas poorly differentiated tumors have a markedly higher metastasis rate. Using these clusters it has been possible to predict the logistically transformed probability of metastasis to a high degree of accuracy (R=0.9398). From this we conclude that if for a given tumor we know to which site, size or differentiation cluster it belongs, we can then estimate its probability of metastasising.