Predictors of locoregional recurrence in early stage oral cavity cancer with free surgical margins.

Locoregional recurrence in patients with early stage oral cavity squamous cell carcinoma (ESOSCC) after surgery remains a problem and can affect their survival. We sought to identify new high-risk factors in these patients, who need further adjuvant therapy. We retrospectively reviewed records for 148 patients who underwent surgery for ESOSCC between 2002 and 2006 with negative surgical margins. The primary endpoint was locoregional recurrence. Recurrence-free survival (RFS) and overall survival (OS) were calculated by the Kaplan-Meier method. Univariate and multivariate analyses were used to identify independent predictors of locoregional recurrence. All patients were grouped into the low- and high-risk groups according to the odds ratios (OR) of the predictors. Recurrence rates of the low- and high-risk groups were then predicted. Recurrence was observed in 17 of 148 (11.5%) patients at the end of this study. None of the patients received postoperative radiotherapy or chemotherapy. At 3 years, the RFS rate was 89.7% and the OS rate at 3 years was 84.1%. Univariate analysis of the RFS revealed three significant prognostic factors: lymphovascular permeation (LVP, p<0.001), perineural infiltration (PNI, p=0.08), and non-T4 muscular invasion (non-T4MI, p<0.005). Multivariate analysis demonstrated that LVP (p=0.007, OR=10.7) and non-T4 MI (p=0.001, OR=8.347) were independent predictors. The recurrence rate was 1.96% in patients without LVP or non-T4MI, and it increased to 26.47% in patients with non-T4MI, to 50% in patients with LVP, and to 50% in patients with both. According to the status of LVP and non-T4MI, patients were divided into two groups: low-risk (no factors present) and high-risk (one or both factors present) groups. The 2-year RFS was lower in the high-risk group (84.13%) than in the low-risk group (93.91%); the 3-year RFS was also lower in the high-risk group (70.49%) than in the low-risk group (91.99%) (p=0.008). Subgroup analysis revealed that elective neck dissections did not affect the outcome or change the pattern of failure. For patients with elective neck dissections, the RFS was lower in the high-risk group than in the low-risk group (p=0.03). In ESOSCC (pT1-2N0), LVP and non-T4MI significantly increased the recurrence rate. The presence of one or both factors (LVP and/or non-T4MI) should be considered as a high-risk condition for locoregional recurrence, and adjuvant therapy is needed in such cases.