ORAL AND OROPHARYNGEAL SQUAMOUS CELL CARCINOMA ASSOCIATED WITH PRECURSOR LESIONS: A STUDY OF CANCER DATA IN ONTARIO, CANADA

Abstract

<h3>Background</h3> Oral and oropharyngeal squamous cell carcinoma (OSCC) is commonly preceded by preinvasive lesions. These are collectively described as oral potentially malignant disorders (OPMDs). We hypothesized that OSCCs that are associated with a previously diagnosed OPMD have better clinical outcomes. <h3>Objective</h3> To determine the clinical characteristics and outcomes of OSCC diagnosed in Ontario and compare cases with or without previous biopsy-proven OPMD. <h3>Methods</h3> We searched for OPMD diagnosed from 2001 to 2015 in the databases of 4 pathology services in Ontario: Oral Pathology Diagnostic Services at University of Toronto, Western University, Mt. Sinai Hospital, and Sunnybrook Health Sciences Centre. The database was linked to the Cancer Care Ontario database (2005-2015) to identify OSCC cases with a preceding OPMD. Variables included age at cancer diagnosis, sex, geographic location of the patient's residence, cancer site, stage, and outcome. <h3>Results</h3> There were 11,213 patients diagnosed with OSCC between 2005 and 2015 and 390 of these patients had a preceding diagnosis of OPMD (3.48%). In addition, 17.12% of patients with OSCC with precursor lesions died of disease, compared with 31.87% of those without a precursor (<i>P</i> < .0001). Stage I disease predominated in patients with precursor lesions (46.71%) and Stage IV disease was more frequent in patients without precursor lesions (56.73%). The proportion of patients with cancer with previously diagnosed OPMD was influenced by the location of patients' residence (<i>P</i> < .0001), suggesting that differences in access to care play an important role. <h3>Conclusions</h3> Clinical and histopathologic diagnosis of OPMD is critical for early cancer detection and leads to improved clinical outcome.