Nodal Disease Burden for Early-Stage Oral Cancer

Question  Does prophylactic neck dissection provide a survival advantage in patients with clinically node-negative (cN0) oral cancer?

Findings  In this population-based retrospective study, patients who received prophylactic neck treatment had no survival advantage compared with those who received local excision only, and a subgroup of patients at who developed neck disease at follow-up received salvage neck treatment and had the worst survival. Tumor depth of invasion of at least 4 mm was significant but had poor sensitivity and specificity in association with nodal disease.

Meaning  New objective markers are urgently needed to identify high-risk patients with cN0 oral squamous cell carcinoma who may benefit from prophylactic neck treatment.

Importance  Nodal disease has a significant effect on survival of patients with oral squamous cell carcinoma (OSCC). The decision for elective neck dissection for clinically node-negative (cN0) disease remains elusive.

Objectives  To determine the efficacy of prophylactic neck treatment and to assess the value of commonly used clinicopathologic factors associated with nodal disease for early-stage OSCC.

Design, Setting, and Participants  This retrospective study from a population-based cancer registry included patients diagnosed as having OSCC from January 11, 2001, to December 24, 2007, who were identified from the British Columbia Cancer Agency Registry. Comprehensive clinicopathologic data, treatment information, and time to outcome were collected. Five-year overall survival, disease-specific survival, and cumulative incidence of regional failure (RF) were analyzed. Receiver operating characteristic curve analysis with sensitivity and specificity was used to determine the association of these covariates with RF during follow-up. Data were analyzed from January 16 to June 30, 2015.

Interventions  Follow-up of patients with cN0 OSCC with or without prophylactic neck treatment (elective neck dissection [END] and or radiotherapy).

Main Outcomes and Measures  Patient demographic characteristics, clinicopathologic data, treatment data, and time from the initial surgery to last follow-up, the development of RF, or death due to oral cancer or other causes.

Results  Of the 469 patients with cN0 primary OSCC who underwent intent-to-cure surgery for the intraoral lesion, 447 received local excision (LE) for the primary tumor (256 men [57.3%] and 191 women [42.7%]; mean [SD] age, 63.3 [14.7] years). Patients who received prophylactic treatment of the neck (n = 125) compared with LE only (n = 322) had no survival advantage. The estimated 5-year overall and disease-specific survival rates were 61.9% (95% CI, 56.5%-67.8%) and 80.8% (95% CI, 76.1%-85.6%), respectively, for the LE-only group; 54.4% (95% CI, 45.9%-64.5%) and 73.1% (95% CI, 65%-82.3%), respectively, for the LE + END ± radiotherapy group; and 61.7% (95% CI, 52.3%-72.8%) and 80.3% (95% CI, 72%-89.4%), respectively, for the LE + END group. Among the patients with cN0 disease receiving LE only, 89 (27.6%; 95% CI, 23%-33%) developed RF at a median time of 10.8 months, and 71 of the RFs (79.8%) developed within 30 months. Tumor depth of invasion of at least 4 mm and tumor grade of 2 or 3 showed an association with RF but had poor sensitivity and specificity.

Conclusions and Relevance  Commonly used pathologic factors to decide neck dissection for cN0 OSCC are not effective and can cause overtreatment or undertreatment. The need for identification of new objective approaches for risk assessment of RF is urgent.