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.