Lymph Node Metastasis in Squamous Cell Carcinoma of the Lip.

Background
Squamous cell carcinoma (SCC) is the second most common skin cancer in Australia. The lip is a high-risk site for lymph node metastasis given the ease of accessing the rich lymphatic system in the muscle beneath. It may be difficult to define the origin of lip tumours as either mucosal or cutaneous, which impacts on treatment with respect to the nodal basin. The most important prognostic factor for overall survival is lymph node metastasis – which can reduce five-year survival by half. The primary aim of the study was to identify factors associated with lymph node metastasis. Recurrence and overall survival were analysed as secondary outcomes. This was performed to identify which patients were high risk and attempt to highlight who would benefit from elective treatment of the nodal basin.

Methods
A retrospective analysis of all lip resections performed over two tertiary hospitals over a five-year period was performed. Data on known risk factors was collected and analysed using univariate and multivariate analyses, as well as cox-proportional hazard modelling.

Results
A total of 290 lip resections were included in the study. 25 patients (25/290, 8.6%) had lymph node involvement at any point in time. Significant risk factors for lymph node metastases were size, depth of invasion and muscle invasion. Recurrence was associated with size, depth of invasion and differentiation grade. Overall survival was significantly reduced by increasing age, immunosuppression and nodal involvement at presentation.

Conclusion
This research is one of the largest studies involving lip SCC and lymph node metastases. Significant factors for each of the outcomes were consistent with previous studies, however there were some differences. It provides a baseline dataset for comparison to establish elective treatment of the nodal basin in high-risk patients with lip SCC.

Craniomaxillofacial/Head and Neck

PSTM 2024