OP192: Perineural invasion in T1 oral sqauamous cell carcinoma indicates the need for aggressive elective neck dissection

Abstract

Purpose Management of cN0 neck remains controversial for T1-2 OSCC (oral squamous cell carcinoma). Perineural invasion (PNI) has been a poor prognostic factor for OSCC, but its significance in T1 OSCC remains unclear. This study investigated the role of PNI, focusing on the controversial issues of neck management in T1 OSCC patients. Materials and methods PNI status was re-evaluated under hematoxylin and eosin staining in tumors of 307 consecutive T1-2 OSCC patients who received surgical treatment. Oncologic and survival outcomes were compared between T1 and T2 patients. Impacts of PNI in T1 OSCC were analyzed by univariate and multivariate analyses. Results The presence of PNI correlated with cervical LN metastasis in both T1 and T2 OSCC, and PNI-positive rate was significantly lower in T1 (17.1% versus 36.6%; P P P P P = 0.399 and P = 0.1478). Of the 146 patients with T1 OSCC, PNI remained independently predictive of cervical LN metastasis, neck recurrence and poor DSS. Elective neck dissection significantly reduced neck recurrence in PNI-positive ( P = 0.001) but not in PNI-negative patients ( P = 0.114). Elective neck dissection also improved the 5-year DSS rate more obvious, although not statistically significant, in PNI-positive than in PNI-negative patients (16.2% versus 5.4%). Conclusions PNI independently predicts poor prognosis in patients with T1 OSCC who are potentially curable but tend to be treated conservatively. Elective neck dissection should be performed for T1, PNI-positive patients for its efficacy in improving neck recurrence and survival.