IntroductionOral cavity cancer with the masticator space involvement is considered as very advanced localised diseas e and staged as T4b in AJCC 8th edition. NCCN guidelines consider this as inoperable. This study intends to compare the different treatment modalities in T4b oral cavity cancer and their impact on survival. Patients and methodsThis is a retrospective study of 150 patients with T4b oral cavity ca, from 2013to 2015 and follow up data till 31 st July 2019 were collected. All patients had biopsy proven SCC and CT evidence of masticator space involvement. ResultsTotal of 150 patients were included. 102 patients had received curative treatment and 48 patients had received palliative treatment. In the curative group 84% were treated with surgery and adjuvant treatment and remaining had received RT with or without chemotherapy. 90% patients in the surgically treated group had attained margin negative resection. 4 year OS in the curatively treated group was 58.9% and in the palliative group was 12%. The surgically treated patients in the curative arm had a significant survival advantage over the patients who had received only RT with or without chemotherapy, (63.5% v/s 34%, p = 0.001). ConclusionCuratively treated oral cavity cancer with masticator space involvement has survival outcome comparable to the published survival data of those without masticator space involvement. Radical intent treatment, preferably surgery should be offered to all patients with masticator space involvement, if negative margin is anticipated from preoperative imaging