Mucosal Margin Shrinkage in Oral Cavity Cancer: A Systematic Review

Introduction: Tissue shrinkage can make planning of surgical margins difficult due to variability between planned in vivo margins and final ex vivo margins on histopathology. While shrinkage of resected oral cavity mucosa is a well-described phenomenon, current data quantifying these effects are variable.

Methods: PubMed, Embase, Web of Science, and Cochrane Library were searched from inception to October 2024. The search strategy was crafted with the assistance of a medical librarian to find studies reporting post-resection shrinkage of surgical margins in oral cavity cancer using a combination of keywords and subject headings. Cohort studies reporting mean percent change in margin size in patients who underwent primary resection for oral cavity cancer with no prior radiation were included. Data extraction and quality assessment were performed by two independent reviewers.

Results: The search identified 10 studies that met inclusion criteria, accounting for 308 patients who underwent primary resection of oral cavity cancer. Mean percent margin shrinkage from pre- to post-resection ranged from 14.9-22.7%, from post-resection to post-fixation ranged from 3.7-25.6%, and from pre-resection to post-fixation ranged from 11.3-59.0%. In studies reporting pre-resection, post-resection, and post-fixation margins (2 studies), shrinkage of margins from pre- to post-resection was significantly larger than shrinkage between post-resection to post-fixation. In studies that reported shrinkage by T stage (2 studies), shrinkage in T1/T2 tumors was significantly larger than in T3/T4 tumors. In studies that reported shrinkage by tumor subsite (4 studies), there was no significant difference between shrinkage of buccal mucosa, oral tongue, and other subsites.

Conclusions: Oral cavity tissue undergoes shrinkage both after surgical resection and after fixation with formalin, with the most significant shrinkage occurring immediately after resection. Given the change from in vivo margins to final histopathologic margin evaluation, tissue shrinkage should be an important consideration in the planning of surgical margins.