Prevalence of occult cervical lymph nodes metastasis in CN0 in oral squamous cell carcinoma (OSCC)

Occult metastasis is not easily detected clinically or radiographically. Various methods have been applied for neck control for clinically N0 via elective neck dissection (END), wait and watch (W&W) and sentinel lymph node biopsy (SLNB). The main aim of this study is to investigate the prevalence of occult cervical lymph nodes metastasis in cN0 in oral squamous cell carcinoma, to investigate and compare the disease-free state and overall survival rate between occult metastasis and the non-occult group that presented at the oral and maxillofacial surgery clinic, Faculty of Dentistry, Universiti Malaya. This is a retrospective study involving 48 patients with complete data from 2008 to 2019. Data collected includes socio-demographic and clinicopathologic factors. Descriptive analysis was performed and Kaplan-Meier analysis was used to compare disease-free status and overall survival period between occult and non-occult metastases groups. The prevalence of occult metastasis in oral squamous cell carcinoma (OSCC) was low at 8.3 % but it became 100 % on OSCC tongue. The main tumor site for occult metastasis originated from the oral tongue with T2 size. Non-occult group had better overall survival rate comparing to occult metastasis group and the advanced group. Therefore, END is recommended particularly for N0 OSCC tongue.