Prediction score for lymph node metastasis from cutaneous squamous cell carcinoma of the external ear

Abstract

Aims: The frequency of lymph node metastasis (LNM) is higher in cutaneous squamous cell carcinoma (cSCC) of the ear than in other head and neck cSCCs. Nodal dissemination is associated with a significantly worse prognosis and disease-specific survival. The aim of this study was to establish a prediction model for LNM in patients with cSCC of the ear.

Materials and methods: Tumour characteristics of 353 patients with ear cSCC were analysed to assess differences between those with and without LNM and to calculate a prediction score for LNM occurrence.

Results: Regional LNM occurred in 10.5% of patients. Five-year disease-specific survival was significantly lower in the LNM group than in the control group (59% vs. 99%; p < 0.001). Recurrence number, invasion of cartilage, tumour depth, and tumour grading were the most important predictors for LNM, with correct prediction of LNM in 94.0% of cases. Our prediction score stratified patients into high and low risk groups (p < 0.001) with a sensitivity of 89.2%, a specificity of 94.6%, and an overall accuracy of 94.1%.

Conclusion: Our new prediction model was able to accurately identify patients at high risk of LNM who may benefit from elective lymph node surgery.

Keywords: Ear neoplasms; Lymph node excision; Lymphatic metastasis; Prognosis; Squamous cell carcinoma.