Evaluation of resection margins in oral squamous cell carcinoma

Abstract

Introduction: Surgery is the primary treatment modality for oral squamous cell carcinoma. The purpose of the surgical procedure is complete removal of the tumor with a sufficient margin of healthy tissue in its surroundings. Resection margins represent an important factor for planning further treatment and for estimation of the disease prognosis. Resection margins can be divided into negative, close and positive. Positive resection margins are considered a prognostically unfavorable factor. However, the prognostic significance of close resection margins is not entirely clear. The aim of this study was to evaluate the relationship between resection margins and disease recurrence, disease-free survival and overall survival.

Material and methods: The study included 98 patients who underwent surgery for oral squamous cell carcinoma. During histopathological examination, resection margins of each tumor were evaluated by a pathologist. The margins were divided into negative (> 5 mm), close (0-5 mm), and positive (0 mm). Disease recurrence, disease-free survival and overall survival were evaluated according to the individual resection margins.

Results: Disease recurrence occurred in 30.6% of patients with negative, 40.0% with close, and 63.6% with positive resection margins. Significantly shorter disease-free survival and shorter overall survival in patients with positive resection margins was proven. The five-year survival rate was 63.9% in patients with negative, 57.5% with close, and only 13.6 % with positive resection margins. The risk of death was 3.27times higher in patients with positive resection margins compared to patients with negative resection margins.

Discussion: Positive resection margins represent a negative prognostic factor, which was also confirmed in our study. There is no unequivocal consensus on the definition of close and negative resection margins and also on the prognostic significance of close resection margins. Factors that may contribute to inaccuracy in the evaluation of resection margins include tissue shrinkage after excision and after fixation of specimens before the histopathological examination.

Conclusion: Positive resection margins were associated with a significantly higher incidence of disease recurrence, shorter disease-free survival and shorter overall survival. When comparing the incidence of recurrence, disease-free survival, and overall survival between patients with close and negative resection margins, the differences were not statistically significant.

Keywords: oral squamous cell carcinoma; pathological examination; prognostic factor; resection margins; survival.