ASO Visual Abstract: Is the N 2A Category Still Necessary for Oral Cancer Patients After Extranodal Extension Upgrade?

The presence of single-node metastasis (Ns) sometimes could be encountered in patients with oral squamous cell carcinoma (OSCC). The survival outcome for different Ns should be worthy of discussion. Patients diagnosed with OSCC at the National Taiwan University Hospital between January 2007 and December 2018 were reviewed. All patients with Ns were classified into two groups: with and without extranodal extension (ENE). We analyzed 311 OSCC patients with Ns: 77 (24.76%) with and 234 (75.24%) without ENE. Lymph node (LN) >3 cm was the only significant factor associated with ENE (odds ratio 17.21, p < 0.001). The 5-year, disease-free survival of N1/N2A and N3B patients was 60.5% and 49.4%, respectively (p = 0.04), and the 5-year overall survival was 63.1% and 33.6%, respectively (p = 0.0001). Four fifths of Ns patients with LN >3 cm were upgraded to N3B category as ENE+. Postoperative radiotherapy (PORT) could provide significant benefit in regional control for Ns patients with (p = 0.03) and without (p = 0.0004) other adverse features. After multivariant Cox analysis, ENE+ was a modest and significant risk factor for disease-free (p = 0.08) and overall survival (p = 0.001). By contrast, the LN>3cm and N2A category were not significant risk factors for disease-free and overall survival. For OSCC patients with Ns, the survival outcome between N3B category and N1/N2A category was significantly different. After ENE+ upgrades (>80%), there were fewer N2A patients, and these patients became more comparable to N1 patients. PORT could significantly improve regional control for Ns patients.