RESUMO
<p><b>BACKGROUND</b>Sinonasal inverted papilloma (IP) is a rare benign tumor of the nasal cavities and paranasal sinuses. It is destructive or bone-remodeling, tends to recur after surgical resection, and has a significant malignant potential. The present study aimed to perform a retrospective analysis of patients with squamous cell carcinoma (SCC) arising from IP, including characteristics, survival outcome, and predictors of associated malignancy.</p><p><b>METHODS</b>The medical records of 213 patients diagnosed with IP from January 1970 to January 2014 were retrospectively reviewed. Eighty-seven patients were diagnosed with SCC/IP; their clinical characteristics, treatments, and survival outcomes were analyzed.</p><p><b>RESULTS</b>Of the 87 patients with SCC/IP, the 5- and 10-year overall survival outcomes were 39.6% and 31.8%, respectively. Twenty-nine of these patients received surgery and 58 received combined surgery and radiation. Of the patients with stages III-IV, the 5-year survival rate was 30.7% for those treated with surgery only and 39.9% for those given the combination treatment (P = 0.849). Factors associated with significantly poor prognosis were advanced-stage, metachronous tumors, or with cranial base and orbit invasion. Age, synchronous or metachronous tumors, and pathological stage were independent risk factors for mortality, shown by multivariate analysis.</p><p><b>CONCLUSION</b>Patients with SCC/IP had low overall survival outcomes. Advanced age, stage, and metachronous tumors are the main factors affecting prognosis. Treatment planning should consider high-risk factors to improve survival outcome.</p>