Impact of biopsy-related variables on MRI assessment of tumor invasion in early oral squamous cell carcinoma

Objective: To evaluate the impact of incisional biopsy technique and biopsy-to-MRI interval on the concordance between radiological and pathological depth of invasion (DOI) in early-stage oral squamous cell carcinoma (OSCC). Methods: A retrospective cohort study included 47 patients with early-stage OSCC who underwent incisional biopsy, MRI, and surgical resection. After excluding non-invasive tumors and cases with unreliable radiological DOI (r-DOI) assessment, 22 patients were analyzed. r-DOI was independently measured by two radiologists and compared with pathological DOI (p-DOI) from surgical specimens. The effects of biopsy technique ("cold blade" vs. "forceps") and biopsy-to-MRI interval on DOI concordance were evaluated using Lin's concordance correlation coefficient, Bland-Altman analysis, and the Mann-Whitney test. Results: MRI overestimated DOI by a mean of 2.95 ± 2.71 mm compared with pathology (limits of agreement: -2.37 to 8.26 mm), showing weak-to-moderate concordance (Lin's CCC = 0.494, 95% CI: 0.23-0.69; Spearman's ρ = 0.563, 95% CI: 0.18-0.80). DOI discrepancy was not significantly associated with biopsy technique (p = 0.61) or biopsy-to-MRI interval (p = 0.79). Conclusions: MRI tends to overestimate DOI in early-stage OSCC irrespective of biopsy technique or imaging timing. Given the prognostic importance of prompt treatment, delaying MRI to reduce presumed biopsy-related overestimation appears unjustified. Clinical relevance: MRI systematically overestimates DOI compared with final histopathology, but this discrepancy does not appear to be influenced by biopsy technique or biopsy-to-MRI interval. Although larger, adequately powered studies are needed, these findings do not support delaying MRI solely to minimize presumed biopsy-related effects on DOI assessment.