Long-term survival and risk factors of synchronous bone metastasis in oral tongue squamous cell carcinoma patients

The objective of this study was to analyze the risk factors for synchronous bone metastases in patients with oral tongue squamous cell carcinomas (OTSCC). OTSCC patients were extracted from the Surveillance, Epidemiology and End Results database between 2014 and 2017. We examined the association between risk factors and synchronous bone metastases using Chi-squared tests. Predictors of survival rates were assessed using univariate and multivariate analyses. A total of 3902 patients were analyzed, which include 12 patients (0.3%) with synchronous bone metastases and 3890 patients without synchronous bone metastases (99.7%). Multivariate logistic regression analysis showed that highly differentiated disease, lower T classification, and lower N classification were associated with a significantly lower risk of bone metastases (P < 0.05, respectively). Unmarried and elderly patients who harbored with poorly differentiated disease, higher T or N classification, multiple sites of metastases, and no surgical therapy to primary tumor were more likely to influence patients' survival. By analyzing data from a large cohort, factors affecting bone metastases are primarily related to grade, T classification and N classification. Multivariable analysis showed that unmarried and elderly patients who harbored with poorly differentiated disease, higher T or N classification, multiple sites of metastases, and no surgical therapy to primary tumor were more likely to influence patients' survival. More accurate assessments of bone metastasis will be imperative for early diagnosis and treatment in poorly differentiated disease, higher T classification or N classification patients.