Clinicopathologic Determinants of Outcome in Pathologic T4a (pT4a) Squamous Cell Carcinoma of the Gingivobuccal Subsite of the Oral Cavity

Carcinoma of the gingivobuccal complex is one of the most common cancers in India and patients usually present in an advanced stage. There is limited data in literature regarding the factors predicting outcome in pathological T4a patients. In this study, we aimed to study the clinic-pathological factors which may influence treatment outcomes in pT4a patients. This is a retrospective study of 121 patients who underwent surgery for oral squamous cell carcinoma between August 2011 and December 2016, staged pT4a. Overall survival (OS) and disease-free survival (DFS) were analyzed for variables including age, depth of invasion, margin status, differentiation, nodal status, extranodal spread, lymphovascular and perineural spread, and adjuvant treatment. The study cohort comprised 93 males with mean age 60.28 years (S.D. 11.25). Median DFS was 21 months (range 9 to 2374 days) whereas median OS was 24.5 months (range 9 to 2374 days). On univariate analysis, lymphovascular invasion, perineural invasion, cervical nodal metastasis, and extranodal extension had a statistically significant effect on both DFS and OS. On multivariate analysis, age ( p = 0.014) and adjuvant radiotherapy ( p = 0.010) were the statistically significant factors affecting OS. None of the factors affected DFS on multivariate analysis. Patients staged pT4a with cervical nodal metastasis, extranodal extension, lymphovascular invasion, and perineural invasion have reduced OS and DFS. On multivariate analysis, lower age at presentation and adjuvant radiation improved patient outcome.