When should patients with T1N0 oral squamous cell carcinoma be considered for elective neck dissection?

Aims: To identify adverse pathological features (APF) predicting nodal failure in clinically node negative T1 oral squamous cell carcinoma (OSCC). Methodology: This study evaluated patients with T1N0 (≤5 mm depth of invasion (DOI) and ≤2 cm diameter) oral cancers from a prospectively maintained database between 1988 and 2020. All patients underwent surgical excision of the primary lesion without neck dissection. Patients underwent three monthly clinical surveillance and salvage neck dissection was performed if nodal relapse was diagnosed. Results: Overall, 141 patients were included. Nodal relapse was reported in 16/141 (11.3%) patients. Factors impacting regional recurrence-free survival were DOI ≥3 mm (HR: 2.4, P < 0.001), maximum tumour diameter ≥12 mm (HR: 1.1, P = 0.009), perineural invasion (PNI) (HR 7.5, P = 0.002) and poor differentiation (HR 5.3, P = 0.01). Rates of nodal relapse increased from 2% amongst patients with no APFs to 100% for those with four APFs. Patients with two or more APFs had significantly poorer 5-year regional recurrence-free survival (94.8% vs. 56.3%, P < 0.001). Conclusion: Patients with T1N0 OSCC with two or more APFs (DOI ≥3 mm, diameter ≥12 mm, PNI or poor differentiations) should be considered for elective neck dissection.