Marginal Mandibulectomy in Oral Cavity SCC: Experience in a Tertiary Care Centre.

Abstract

Marginal mandibulectomy is indicated for oral cavity squamous cell carcinomas that involve floor of mouth, abut or minimally erode the mandible without gross invasion. Successful outcomes after Marginal mandibulectomy is predicated on accurate patient selection and appropriate adjuvant treatment based on specific host and tumor characteristics. To study the onclogical outcomes in terms of loco-regional recurrence free survival and disease specific survival of marginal mandibulectomy done for oral squamous cell carcinomas. Study Design-Retrospective study. Setting-The study was done from January 2018 to January 2021 at our tertiary care centre Madras Medical College, Chennai. Subjects-30 cases were included in our study who underwent Marginal Mandibulectomy for oral cavity SCC. Methods-The decision to perform a marginal mandibulectomy was taken based on preoperative clinical examination, contrast enhanced computed tomography (CECT) findings and intra-operative assessment under anesthesia. Disease-free survival, cause-specific survival, and local control rates were plotted using the Kaplan-Meier method. Oncologic outcomes in terms of Overall survival and Disease-specific survival at the end of 1 year and 3 years for the gingival, buccal, tongue, floor of mouth cancers were analyzed. Independent impacts including the site of tumor, T and N stage, microscopic bony invasion, grade of differentiation, adjuvant radiotherapy on the loco-regional control and cause-specific survival were evaluated using Kaplan meier method. Our study group was comprised of 20(66.67%) males and 10 (33.33%) females of mean age 54 years. None of them had prior radiotherapy to the head and neck region. A total of 7 (23.33%) marginal mandibulectomies were carried out for SCC in the gingival region, 11(36.67%) for buccal mucosa, 8(26.67%) for tongue, 2(6.67%) for floor of mouth SCC, 1(3.33%) involving lip, 1(3.33%) in Retromolar trigone. Clinically 2 (6.67%) patients had T1 cancer, 18 (54.54%) had T2, 6 (18.18%) had T3, 4(13.33%) had T4 tumor. Clinically Neck nodes were not palpable in 17 (56.67%) patients, 10 (33.33%) had N1 disease and 3 (10%) had N2 disease. T and N stage distributions for tongue/floor of mouth and gingival buccal complex cancers are summarized in the table and there were no statistically significant differences between the 2 groups. 19 (63.33%) had selective neck dissection (levels I-III), and 11 (36.67%) had comprehensive neck dissection. Well-differentiated tumors were encountered in 12 (40%) cases, moderately differentiated tumors in 16 (53.33%) cases, and poorly differentiated tumors in 2 (6.67%) cases. Bone was microscopically involved in 4 (13.33%) cases and mucosal margin of excision was less than 5 mm from the tumor in 2 (6.67%) cases. Cumulative hazard of local recurrence was not significantly affected by mandibular involvement. On histopathologic examination, positive nodes were seen in 6(20%) cases that included 3 (10%) with pN1 and the rest with pN2 disease. Adjuvant radiotherapy (56 to 64 Gy) was given to 13 (43.33%) patients. In carefully selected patients, marginal mandibulectomy in oral squamous cancer achieves good oncological outcome in terms of locoregional control and overall survival rates.