Is the N Category Still Necessary for Oral Cancer Patients After Extranodal Extension Upgrade?

Background: 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.

Methods: 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).

Results: 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 N/N and N 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 N 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 N category were not significant risk factors for disease-free and overall survival.

Conclusions: For OSCC patients with Ns, the survival outcome between N category and N/N category was significantly different. After ENE+ upgrades (>80%), there were fewer N patients, and these patients became more comparable to N patients. PORT could significantly improve regional control for Ns patients.