Clinical Impact of Surgical Margin Status on Local Control and Survival Following Oral Cancer Surgery

Abstract

Background:

Surgical margin status is one of the most important prognostic determinants in oral squamous cell carcinoma (OSCC), influencing local tumor control and long-term survival. Despite advances in surgical techniques, close and positive margins remain associated with unfavorable oncological outcomes. This study evaluated the impact of surgical margin status on recurrence and survival in patients undergoing curative surgery for oral cancer.

Materials & Methods:

A retrospective observational study was conducted on 180 patients with histopathologically confirmed OSCC who underwent primary curative surgical resection. Patients were categorized into three groups according to final histopathological surgical margin status: negative margin (n = 60), close margin (n = 60), and positive margin (n = 60). Baseline demographic characteristics, tumor stage, nodal status, local recurrence, disease-free survival (DFS), overall survival (OS), and overall oncological outcomes were compared among the three groups. Continuous variables were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's Honestly Significant Difference (HSD) post hoc test, whereas categorical variables were analyzed using the Chi-square test. Univariate Cox proportional hazards regression analysis was performed to identify prognostic factors associated with adverse oncological outcomes. A p-value <0.05 was considered statistically significant.

Results:

Baseline demographic characteristics were comparable among the three groups (age, p = 0.721; gender, p = 0.842). Advanced tumor stage (p = 0.018) and nodal involvement (p = 0.024) were significantly associated with close and positive surgical margins. Local recurrence increased progressively from 13.3% in the negative margin group to 26.7% in the close margin group and 45.0% in the positive margin group (p < 0.001). Mean DFS was significantly higher in patients with negative margins (48.20 ± 10.60 months) than in those with close (38.90 ± 11.40 months) and positive margins (28.50 ± 12.20 months) (F = 43.281, p < 0.001). Similarly, mean OS was significantly greater in the negative margin group (56.40 ± 8.90 months) compared with the close (47.80 ± 10.10 months) and positive margin groups (36.20 ± 12.80 months) (F = 52.014, p < 0.001). Tukey's HSD analysis demonstrated significant differences between all pairwise comparisons (p < 0.001). Univariate Cox regression identified positive surgical margins (HR = 3.18, 95% CI: 2.01–5.02), advanced tumor stage (HR = 2.64), positive nodal status (HR = 2.31), perineural invasion (HR = 2.05), close margins (HR = 1.91), poor differentiation (HR = 1.82), and lymphovascular invasion (HR = 1.74) as significant predictors of poor oncological outcomes (all p < 0.05). Patients with positive margins exhibited the highest recurrence and mortality rates and the lowest disease-free and overall survival.

Conclusion:

Surgical margin status is a strong independent prognostic indicator in OSCC. Histologically negative surgical margins are associated with significantly lower recurrence rates and superior DFS and OS, whereas close and positive margins adversely affect long-term oncological outcomes. Achieving adequate margin clearance during primary surgical resection remains essential for optimizing prognosis in patients with oral cancer.