Clinical study of mode of invasion in tongue squamous cell carcinoma

Objective: The most commonly used system of classification for the evaluation of histological malignancy in oral squamous cell carcinoma is the Yamamoto-Kohama (Y-K) classification, which focuses on the shape of tumor cell cords at the tumor-host interface, an item also included in the Jakobsson and Anneroth classifications. In this clinical study, we investigated the relationship between mode of invasion as based on the Jakobsson and Y-K classifications and prognosis in patients with tongue squamous cell carcinoma treated at our department. Patients and methods: One hundred and sixty-eight of the 193 patients with tongue squamous cell carcinoma treated in at our department over an 11-year period between 2000 and 2010 were included in this study (25 were excluded as the mode of invasion could not be determined according to the Y-K classification). Results: According to the Jakobsson classification, 26, 33, 53, and 56 tumors were classified as grades 1-4, respectively. According to the Y-K classification, 26, 33, 53, 31, and 25 tumors were classified as grades 1-3, 4C, and 4D, respectively. Conclusion: Patients with grade 4C/4D tumors had many poor prognostic factors, including a pN-positive rate of 73.5%, mortality, recurrence, and late metastasis rate of 44.2%. The tumors in this group exhibited both endophytic and exophytic growth patterns, and the 5-year-survival rate was significantly lower than that in patients with other grade tumors. These results suggest that grade 4C/4D is a useful prognostic factor. (C) 2013 Asian AOMS, ASOMP, JSOP, JSOMS, JSOM, and JAMI. Published by Elsevier Ltd. All rights reserved.