Elective Neck Dissection Improves Regional Control in cN0 Minor Salivary Gland Carcinoma in the Oral Cavity

Abstract

Consensus regarding whether elective neck dissection (END) provides better outcomes than observation in clinically node negative minor salivary gland (MSG) carcinoma is lacking. Therefore, this study aimed to compare the impact of END with that of observation on regional control (RC) and overall survival (OS) and to detect the predictors for lymph-node metastasis in oral MSG carcinoma. A single-institution, retrospective cohort study was designed; it included patients with clinically node negative oral MSG carcinoma treated at a tertiary teaching hospital between January 2002 and January 2022. The primary predictor variable was END and primary outcome variables were RC and OS. The secondary outcome variable was lymph-node metastasis. Other covariates included demographic and pathologic features, TNM stage, and adjuvant treatment. The Kaplan-Meier method and Cox proportional hazards model were used to determine the effect of END on RC and OS. The chi-squared test and logistic regression models were used to identify independent predictors for lymph-node metastasis. A total of 268 patients (107 men and 161 women) with a mean age of 46.4±15.5years were included. The 5-year RC rate was statistically different between the observation and END groups (75%; 95% confidence interval [CI], 67%-83; 95% CI, 81%-93%, respectively; P=.014). Cox regression analysis confirmed that END (hazard ratio [HR] 2.395; 95% CI: 1.433-8.275; P=.034) was independently associated with a decreased risk of regional recurrence. The 5-year OS rates for the observation and END groups were 66% (95% CI, 56-76%) and 76% (95% CI, 66-86%), respectively, and the difference was not statistical (P=.057). Occult metastasis occurred in 24.6% of patients. Primary tumor location on the tongue/floor of the mouth (odds ratio [OR], 4.287; 95% CI, 1.773-9.125; P=.011), T3/4 stage (OR, 3.286; 95% CI, 1.228-8.253; P=.021), and high-grade disease (OR, 6.674; 95% CI, 2.199-14.326; P<.001) were independently associated with an increased risk of occult metastasis. RC was better with END than with observation, but OS was comparable with the two approaches. Primary tumor location on tongue/floor of the mouth, T3/4 stage, and high-grade disease were associated with an increased risk of lymph-node metastasis.