Multicenter retrospective study of the prognosis and treatment outcomes of Japanese oral squamous cell carcinoma patients with level IV/V metastasis

Background: The purpose of this study was to retrospectively describe the characteristics and outcomes of patients with oral squamous cell carcinoma and level IV/V metastasis and to compare patients who underwent no postoperative therapy with those who underwent postoperative radiotherapy (RT) and concomitant chemoradiotherapy (CCRT). Methods: We evaluated 669 patients. Clinicopathological data, postoperative therapy, and clinical course were investigated. Results: Sixty-one patients (9.1%) developed level IV/V metastasis. The 3-year cumulative overall survival rates of patients with and without level IV/V metastasis were 47.3% and 64.3%, respectively. Tongue tumors, pN2 or N3 classification, and moderate or poor differentiation were significantly associated with the development of level IV/V metastasis. The surgery+RT/CCRT group was associated with better 3-year cumulative disease-specific survival and overall survival rates than the surgery only group. Conclusion: Adjuvant therapy (RT alone or CCRT) after surgery is recommended for patients with level IV/V metastasis.