The Indications for Elective Neck Dissection in T1N0M0 Oral Cavity Squamous Cell Carcinoma.

PURPOSE

The management of the clinically node-negative neck in T1 oral cavity squamous cell carcinoma (SCC) is controversial. The purpose of this study was to investigate tumor characteristics of surgically managed patients with T1N0 oral cavity SCC and determine the possible benefits of elective neck dissection (END).

MATERIALS AND METHODS

A retrospective cohort study was conducted assessing outcomes for patients with stage I oral SCC at Waikato Hospital, New Zealand, between 2008 and 2018. Clinical staging was based on the American Joint Committee on Cancer Cancer Staging Manual, 8 Edition. Patients with T1N0 SCC either had an END or had the neck observed. These data were used to determine the rate of occult nodal disease, recurrence rate, and survival. Data collected included patient demographics, location, tumor characteristics including differentiation, depth of invasion (DOI), perineural invasion (PNI), lymphovascular invasion, closest histologic margin, management of the neck, the number of pathologic lymph nodes, adjuvant treatment, recurrence, and survival.

RESULTS

A total of 70 patients were included in the study (40 male, 30 female; age range 30 to 91; mean age 65 years). Twenty-seven (38.6%) patients underwent END, whereas 43 patients (61.4%) were observed. Occult nodal metastases were diagnosed in 6 of 27 (22.2%) patients who underwent END. Regional relapse occurred in 7 of 43 (16.3%) patients who were observed. Risk factors for nodal disease included increasing DOI ≥ 3 mm (P = .049), poor tumor differentiation (P = .003), and presence of PNI (P = .002). Negative prognostic factors for overall survival included male gender (P = .02, hr = 3.55, CI for HR (1.18, 10.65)), presence of PNI (P = .001, hr = 4.52, CI for HR (1.77, 11.57)), and locoregional recurrence (P < .005, hr = 6.55, CI for HR (2.69, 15.98)). Six of the 7 tumors that relapsed in the neck after observation had a primary tumor DOI < 3 mm.

CONCLUSIONS

There is little data published for management outcomes of the node-negative neck in stage I oral squamous cell carcinoma. Given salvage neck dissection carries a poorer prognosis, END should be recommended for all T1N0 oral SCC with DOI ≥ 3 mm. In cases of DOI < 3 mm undergoing primary ablation only, a staging neck dissection as a second procedure should be considered in the presence of poor tumor differentiation or PNI on final histology.