Prophylactic neck dissection in early oral tongue squamous cell carcinoma 2.1 to 4.0 mm depth.

OBJECTIVE Regional recurrence is common following surgery for T1/T2 oral tongue squamous cell carcinoma (SCC). Tumor depth >4.0 mm is commonly assigned as an indication for prophylactic neck dissection to improve regional control. Prophylactic neck dissection may detect extracapsular extension, a poor prognostic sign where adjuvant chemotherapy is indicated. The hypothesis in this study is that regional recurrence is a significant problem in 2.1- to 4.0-mm-depth tumors, and detection of extracapsular extension may be important in this group. STUDY DESIGN Retrospective chart review. SETTING Australian tertiary referral center. SUBJECTS AND METHODS Review of all patients with T1/T2 oral tongue SCC treated surgically between January 1991 and January 2009 (n = 81). RESULTS Twenty-nine prophylactic and 5 therapeutic neck dissections followed for a median 34 months (range, 4-132 months). Tumor depths were 0 to 2.0 mm (n = 15), 2.1 to 4.0 mm (n = 18), 4.1 to 7.0 mm (n = 26), and >7.0 mm (n = 22). Tumors 2.1 to 4.0 mm depth had similar rates of occult nodes as 4.1 to 7.0 mm depth (25% vs 20%). Regional recurrence occurred in 31% overall, 44% in tumors 2.1 to 4.0 mm, and 27% in tumors 4.1 to 7.0 mm depth. Prophylactic neck dissection reduced regional recurrence (17% vs 43%, P = .02). Patients with pathologically negative necks had lower rates of regional recurrence than those with occult nodes (9% vs 50%, P < .01). Extracapsular extension increased regional recurrence (43% vs 7%, P = .02), including 25% of dissected necks with tumor depth 2.1 to 4.0 mm. CONCLUSIONS Regional recurrence is a significant problem in 2.1- to 4.0-mm-depth T1/T2 tongue tumors. Prophylactic neck dissection may improve regional control in patients with adequate primary resection margins and determine need for adjuvant therapies in 2.1- to 4.0-mm-depth tumors.