Oral squamous cell carcinoma is one of the most frequent types of head and neck cancers in Japan. Although recent reports have shown positive results of non-surgical treatment for advanced head and neck squamous cell carcinoma, including tongue cancer, no clear treatment strategies have been established for oral cancers, except for tongue cancer. To assess appropriate therapies, we conducted a retrospective chart review of 114 Japanese patients with oral cancers that were pathologically diagnosed as squamous cell carcinoma, excluding tongue cancers. The overall and the disease specific 5-year survival rates were 53% and 61%, respectively. Univariate and multivariate analyses revealed a lower stage (I, II, or III) and non-surgical treatment as good and poor prognostic factors of oral squamous cell carcinoma, respectively, based on their hazard ratios of 0.17 (95% CI 0.045-0.60, p = 0.0061) and 5.3 (95% CI 2.7-11, p < 0.0001). Furthermore, impact of surgery was well documented in the operable stage IVa cancers (p = 0.00015). The surgical treatment consisted of the wide resection of the primary tumor and the neck dissection for stage III or IV tumors. The present data also suggest that adjunctive therapy, such as post-operative radiation therapy or post-operative chemo-radiation therapy, shows no survival benefit compared to the surgery alone. We therefore recommend the surgical treatment for advanced oral squamous cell carcinoma in Japanese patients. These results would be helpful in future clinical trials, especially in non-surgical treatment studies of oral squamous cell carcinoma in Japan.
2011 Tohoku University Medical Press