The indications for adjuvant therapy in resected oral tongue cancers are based on both clinical and pathological factors, with clear evidence for adjuvant radiation in patients with pathologically positive neck lymph nodes, positive margins, and extracapsular extension, but the data for patients with no nodal disease are sparse.

To investigate determinants of failure and survival in patients with node-negative oral tongue cancer.

Medical records for patients with oral tongue cancer treated with definitive surgery from 2003 to 2013 were reviewed. All patients were cN0 negative and classified as pathologically node-negative (pN0) if a neck dissection was performed. Patients received adjuvant radiotherapy (RT) or chemoradiotherapy (CRT) based on standard clinical and pathological determinants.

Kaplan-Meier and multivariable (MVA) logistic regression and Cox proportional hazard regression analyses were performed to identify patient, tumor, and treatment characteristics predictive of locoregional control (LRC) and overall survival (OS).

A total of 180 patients met entry criteria, with a median follow-up time of 4.9 years (range, 0.9-12.5 years); 102 patients (56.7%) were female and 42 patients (23.3%) were younger than 45 years at diagnosis. One hundred fifty-three patients (85%) had T1/T2 tumors, and 112 patients (62%) had elective neck dissections with confirmed pN0. Lymphovascular space invasion (LVSI) was present in 36 patients (20%). On MVA, LVSI (OR, 0.06; 95% CI, 0.02-0.19; P < .01) was associated with worse LRC. Elective neck dissection (odds ratio [OR], 2.99; 95% CI, 1.16-7.73; P = .02) and receipt of RT (OR, 7.74; 95% CI, 2.27-26.42; P < .01) were associated with improved LRC. Three-year LRC rates were significantly lower for patients with LVSI (38.8%; 95% CI, 22.8%, 54.6%) than those without LVSI (81.9%; 95% CI, 74.4%, 87.4%). On MVA, only LVSI (hazard ratio, 2.20; 95% CI, 1.19-4.06; P = .01) and age greater than 44 years (hazard ratio, 4.38; 95% CI, 1.34-14.27; P = .01) were associated with worse OS. Three-year OS rates were significantly lower in patients with LVSI (71.3%; 95% CI, 53.2%-83.4%) than those without LVSI (90.3%; 95% CI, 83.8%-94.3%).

Lymphovascular space invasion in patients with node-negative oral tongue cancer treated with upfront definitive surgery is associated with worse LRC and OS. Node-negative oral cavity cancers with LVSI warrant consideration of further adjuvant therapy, which should be further evaluated in a prospective setting.