The importance of lymph node ratio for patients with mandibular infiltration of oral squamous cell carcinoma.

PURPOSE

Lymph node ratio (LNR) essentially improves assessment of prognosis and therapeutic decision making for patients with oral squamous cell carcinoma, as it considers both the number of positive lymph nodes and the number of dissected lymph nodes. Mandibular infiltration by oral squamous cell carcinoma is a vital clinicopathological feature, significantly worsens prognosis. However, to the best of our knowledge, data on the influence of LNR on prognosis for patients with OSCC and mandibular infiltration are not available.

MATERIALS AND METHODS

A retrospective chart review of 89 patients with treatment-naive oral squamous cell carcinoma and histopathologically proven mandibular infiltration (pT4a) was performed. Exclusion criteria were primarily curative intended surgery (radical tumor resection, neck dissection and segmental mandibulectomy) with negative resection margins. Exclusion criteria were neoadjuvant chemoradiotherapy, erosive infiltration of the mandible, T4b classification, perioperative death, unresectable disease, synchronous malignancy, follow-up <3 months, and inadequate information to correctly determine clinicopathological characteristics.

RESULTS

We observed a significant correlation on univariate analysis between locoregional recurrence and pathologic N classification (p = 0.004), perineural invasion (p = 0.005) and lymph node ratio (p < 0.001). On multivariate analysis, lymph node ratio (p = 0.028) was shown to be an independent indicator for locoregional recurrence.

CONCLUSION

LNR predicted locoregional recurrence better than the conventional nodal staging system and therefore might serve as a more precise risk stratification tool. LNR >7% led to a 11.419-fold higher risk for locoregional recurrence of patients with mandibular infiltration due to OSCC.