Quantitative analysis of modes of invasion and lymph node metastases in oral squamous cell carcinoma

The mode of tumor invasion has been suggested to have a relationship to the occurrence of cervical metastasis and to prognosis in oral squamous cell c arcinoma (OSCC). However, a tumor usually does not have a single mode of in vasion, and the importance, if any, of the relative proportions of differen t modes for metastatic potential has not been studied. Forty two cases of O SCC resected with cervical lymph nodes were selected, 20 of which had nodal metastases and 22 which had not. The mode of invasion in the tumor-host in terface was classified as: I- pushing borders, II- bands, III- thin cords, IV - single cells and analyzed in 20 consecutive medium power fields. Also studied were other morphological parameters: perineural and angiolymphatic invasion, tissue eosinophilia, mitosis and intensity of inflammatory infilt rate at the tumor-host interface. The majority of the cases (95.2%) showed two or more modes of invasion. Modes I, II and III occurred with similar fr equency in cases with and without metastases. Mode II was the commonest and most extensive in both groups. No mode of invasion was significantly assoc iated with metastases, independent of its extension. The other morphologica l parameters were neither significantly associated with cervical metastasis . In conclusion, OSCC usually shows two or more modes of tumor invasion if a large extension of tumor-host interface is analyzed. However, the relativ e proportions of the modes have no correlation with the metastatic potentia l.