RESUMO
OBJECTIVE: to compare the rate of occult contralateral neck metastases (OCNM) in oral and oropharyngeal squamous cell carcinomas (SCC) reaching or crossing the midline and to identify risk factors for OCNM. MATERIALS AND METHODS: we conducted a single-center retrospective study of oral and oropharyngeal SCC with contralateral cN0 neck. The cohort was divided into a midline-reaching (MR; approaching the midline from up to 10 mm) group and a midline-crossing (MC; exceeding the midline by up to 10 mm) group. Clinical N-status was assessed by a radiologist specializing in head and neck imaging. All patients underwent contralateral elective neck dissection (END). RESULTS: A total of 98 patients were included in this study, 59 in the MR group and 39 in the MC group. OCNM were present in 17.3% of patients, 20.3% in the MR group and 12.8% in the MC group (p = 0.336). In multivariable analysis, MR/MC status as well as distance from the midline (in mm) were not identified as risk factors for OCNM. Conversely, oropharyngeal primary and clinical N-status above N1 were significantly associated with a higher risk of OCNM, with odds ratios (OR) of 3.98 (95% CI = 1.08-14.60; p = 0.037) and 3.41 (95% CI = 1.07-10.85; p = 0.038) respectively. CONCLUSION: in patients with oral and oropharyngeal SCC extending close to or beyond the midline, tumor origin and clinical N-status should carry the most weight when dictating the indications for contralateral END, rather than the midline involvement in itself.