Is there a role for adjuvant radiation in T1N0 squamous cell carcinoma tongue with adverse pathological features? Factors affecting local control and the development of a scoring system.

e17565 Background: The patterns of recurrence and the prognostic factors of early tongue lesions have been previously described in literature, often grouping T1 and T2N0 tongue lesions together. Adverse pathological features (APFs) have been used to predict nodal spread, but the prognostic factors predicting local recurrences in T1N0 tongue have seldom been described. We aim to evaluate the APFs associated with poor local control and the possible need for escalation of therapy. Methods: A retrospective analysis of 144 patients of pT1N0 squamous cell carcinoma tongue, extracted from our database of 598 patients of oral cavity who underwent wide local excision with neck dissection in a single institution between 2006-2014 were included in our study. Patients who received any adjuvant therapy were excluded. Results: APFs associated with local control were least margin 5 mm (p=0.004), infiltrative margin (p=0.403), depth ≥ 4mm (p=0.136), lymphovascular invasion (p=0.301) and perineural invasion (p=0.342). We derived a scoring system assigning a score to each of these factors out of a total 10 points, based on the hazard ratio for local failure. Patients with a score ≥ 5 points had a 5-year local control rate of ≤ 60%. Conclusions: Having least margin of 5 mm was the greatest predictor of local failure. This would suggest that all patients having a margin of 5 mm need revision, however if they do not have additional APF (score ≤ 4 points), they still have good local control rates (5-year local control rate of 88%) and may be observed. Those who have margins over 5 mm with a total score ≥ 5 may still benefit from adjuvant therapy for local control. Those with margins over 5mm have improved local control rates (p=0.029). [Table: see text]