Factors influencing the incidence and prognosis of second primary tumors in patients with oral squamous cell carcinoma

Background. Although second primary tumors are common in patients with oral squamous cell carcinoma (OSCC), their predisposing factors and treatment guideline remain uncertain. Methods. Three hundred ninety-four patients with OSCC who received radical surgery from January 2002 to December 2009 were retrospectively reviewed. Results. Forty-five patients developed oral second primary tumors. Areca quid chewing, tongue tumors, and nodal metastasis were risk factors for second primary tumors. Multivariate analyses revealed that no second primary tumor (hazard ratio [HR] = 5.046; 95% confidence interval [CI] = 3.704-12.246; p =.003), contralateral neck dissection for ipsilateral second primary tumors (HR = 6.254; 95% CI = 3.027-13.365; p =.007), and postoperative radiotherapy (RT; HR = 3.987; 95% CI = 1.099-10.381; p =.040) were independent favorable prognostic factors. Conclusion. Areca quid chewing, tongue tumors, and nodal metastasis predisposed patients with OSCC to second primary tumor development. Elective dissection of the contralateral neck in patients with second primary tumors ipsilateral to index tumors and postoperative RT for eligible patients should always be considered in the management of oral second primary tumors. (C) 2016 Wiley Periodicals, Inc.