The clinical predictive factors for subsequent distant metastasis in patients with locoregionally advanced oral squamous cell carcinoma

Abstract

Only a small portion of the patients with locoregionally advanced oral squamous cell carcinoma (OSCC) experience subsequent distant metastasis. This study is to evaluate the occurrence of distant metastasis after curative treatment and to explore the predictive factors for subsequent distant metastasis in patients with locoregionally advanced OSCC. The medical records of all patients with locoregionally advanced OSCC without distant metastasis at the time of diagnosis (AJCC stage III, IV but not IVC) who underwent curative surgery with or without adjuvant radiation between 2004 and 2009 were retrospectively reviewed. A total of 628 patients were enrolled, including 562 male and 66 female patients. The 5-year distant metastasis rate was 13.2%. The 5-year disease-free and overall survival rates were 57.0% and 60.3%, respectively. Multivariate analyses revealed that poorly differentiated tumors (HR=2.3 (1.16-4.53), p=0.02) and contralateral neck metastasis (HR=7.55 (3.20-17.83), p<0.001) were independent adverse factors for distant metastasis-free survival. The 5-year distant metastasis rates of 447 patients with well-differentiated tumors, 140 patients with moderately differentiated tumors and 41 patients with poorly differentiated tumors were 12.1%, 18.2%, and 34.1%, respectively. The 5-year distant metastasis rates of 227 patients without neck metastasis, 350 patients with ipsilateral neck metastasis and 51 patients with contralateral neck metastasis were 6.7%, 15.1%, and 55.3%, respectively. Poorly differentiated tumors and contralateral neck metastasis were independent factors for subsequent distant metastasis in patients with locoregionally advanced OSCC.