Worst Pattern of Invasion as a Predictor of Nodal Metastasis in Early-Stage Oral Squamous Cell Carcinoma.

Abstract

About one-third of early stage oral cancer patients have occult nodal metastasis. High grade worst pattern of invasion (WPOI) is associated with an increased risk of nodal metastasis and poor prognosis. However, it still remains unanswered whether to perform an elective neck dissection for clinically node-negative disease or not. This study aims to evaluate the role of histological parameters including WPOI in predicting nodal metastasis in early-stage oral cancers. This analytical observational study comprised 100 patients of early-stage, node-negative, oral squamous cell carcinoma, admitted in the Surgical Oncology Department from April, 2018 till the sample size was reached. The socio-demographic data, clinical history, and findings of clinical and radiological examination were noted. The association of nodal metastasis with various histological parameters like tumour size, degree of differentiation, depth of invasion (DOI), WPOI, perineural invasion (PNI), lymphovascular invasion (LVI) and lymphocytic response was determined. SPSS 20.0 statistical tool; student's 't' test and chi-square tests were applied. While the buccal mucosa was the commonest site, the rate of occult metastasis was highest in the tongue. Nodal metastasis was not significantly associated with age, sex, smoking and primary site. While the nodal positivity was not significantly associated with tumour size, pathological stage, DOI, PNI and lymphocytic response, it was associated with LVI, degree of differentiation and WPOI. Increasing WPOI grade correlated significantly with the nodal stage, LVI and PNI, but not with DOI. WPOI is not only a significant predictor of occult nodal metastasis but can also be a novel therapeutic tool in the management of early-stage oral cancers. In patients with an aggressive WPOI pattern or other high-risk histological parameters, the neck can be addressed with either elective neck dissection or radiotherapy after wide excision of the primary tumor; otherwise, an active surveillance approach can be followed.