Outcome analyses of unusual site neck recurrence in oral cavity cancer

Aim: To understand the frequency, clinical significance, and benefits of salvage therapy in oral cavity squamous cell carcinoma (OSCC) patients with regional nodal recurrence at unusual sites (prelaryngeal area, parotid area, and retropharyngeal area). Methods: We examined 178 patients with neck recurrence at levels I-V (usual group) and 26 patients outside levels I-V (unusual group). The 5-year survival rates served as the main outcome measure. Results: Of the 26 unusual group patients, the neck recurrence sites were as follows: 5 at the prelaryngeal area, 13 at the parotid area, and 8 at the retropharyngeal area. Multivariate analyses demonstrated that poor differentiation, pN2, extracapsular spread (ECS), tumor depth ≥10 mm, relapse time ≤10 months, local recurrence, neck recurrence at unusual sites, and distant metastases were independent prognostic factors for 5-year disease-specific survival (DSS), whereas pN2, ECS, tumor depth ≥10 mm, relapse time ≤10 months, neck recurrence at unusual sites, and distant metastases were independent prognostic factors for 5-year overall survival (OS). The 6-month and 18-month survival rates after the N-relapse date for the salvaged-usual group, the salvaged-unusual group, and the nonsalvaged patients were 73 %/46 %, 40 %/0 %, and 10 %/0 % (P < 0.0001), respectively [DSS: salvaged-unusual group (hazard ratio/95 % confidence interval), 2.060/1.058-4.008, P = 0.033; salvaged-usual group, 6.420/4.340-9.496, P < 0.001; OS: salvaged-unusual group, 2.100/1.080-4.081, P = 0.029; salvaged-usual group, 6.514/4.418-9.606, P < 0.001]. Conclusions: Our findings demonstrate that OSCC patients with regional nodal recurrence at unusual sites had poor outcomes.