Predictive Factors for Submandibular Gland Involvement in Oral Cavity Squamous Cell Carcinoma—a Prospective Study from a Tertiary Cancer Center

The oncological necessity of submandibular gland removal during neck dissection for oral cavity squamous cell carcinoma surgery has remained controversial. This study was aimed to determine the rate of SMG involvement and assess the feasibility of submandibular gland (SMG) preservation. We present a prospective study conducted at a tertiary cancer center from June 2017 to May 2019. All patients of oral squamous cell carcinoma who underwent primary surgery with neck dissection were included and analyzed for incidence and predictive factors for incidence of level IB nodal and SMG involvement as per CAP guidelines. A total of 60 patients were inducted in the study, wherein 63 neck dissections were performed including bilateral dissection in three cases. There was involvement of SMG in 6 patients with two cases each in floor of mouth cancer, gingivo-buccal, and alveolar lesions. The SMG was involved by direct contiguous spread from the primary lesion in two cases, extra-capsular extension from level IB lymph nodes in one and by both mode of spread in three glands. Perineural invasion was seen in 83.33% (n = 5) patients with SMG involvement (p- < 0.001), while 66.67% (4/6) patients had lympho vascular invasion (p-0.006) and all the cases with SMG involvement had extra-capsular extension (p < 0.001), suggesting PNI, LVI, and ECE as the strongest predictors of SMG involvement. This study demonstrates that oral cavity squamous cell carcinoma has low potential to metastasize to the SMG; however, high-risk factors include primary tumor site in floor of mouth or tongue, heavy level IB nodal burden, presence of LVI, PNI, and ECE. In the absence of these high-risk factors, SMG preservation with complete nodal clearance in level IB is a promising technique for reducing future complications.