279P Clinico pathological characteristics and survival outcome in oral cavity cancer with masticator space involvement (T4b): A retrospective single institutional experience

Abstract

Oral cavity cancer with the masticator space involvement is considered as very advanced localised disease and staged as T4b in AJCC 8th edition, along with the involvement carotid artery, base of skull or prevertebral fascia. NCCN treatment guidelines consider this as inoperable disease and advocate non-surgical options or palliative treatment. This study intends to compare the different treatment modalities in T4b oral cavity cancer and their impact on survival. This is a retrospective study of 150 patients with T4b oral cavity cancer, from 2013 to 2015 and follow up data till 31st July 2019 were collected. All patients had biopsy-proven SCC and CT evidence of masticator space involvement. Total of 150 patients were included. 102 patients had received curative treatment and 48 patients had received palliative treatment. 30% in the curative group and 42% in the palliative group were supra notch disease. In the curative group 84% were treated with surgery and adjuvant treatment, and the 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%. 2-year OS was 69% and 31% respectively, (p=0.001). The survival of supra notch disease was not different from infra notch disease either in the curative group (61% v/s 57%, p=0.452) or in the palliative group (10% v/s 14%, p=0.13). The surgically treated patients in the curative arm had significant survival advantage over the patients who had received only RT with or without chemotherapy, (63.5% v/s 34%, p=0.001). Curatively treated oral cavity cancer with masticator space involvement has good survival outcome. Clinicopathological spectrum of supra notch disease is not different from infra notch disease, and their prognosis is similar to infra notch disease, if margin-negative resection is attained. Radical intent treatment, preferably surgery should be offered to all patients with masticator space involvement, if negative margin is anticipated from preoperative imaging.