Role of midline raphe in compartmental surgery for squamous cell carcinoma of the tongue

Abstract

Purpose: In the present study, we investigated how tumor distance from midline (TDFM) and depth of invasion (DOI) may affect survival outcomes after compartmental tongue surgery (CTS) for oral tongue squamous cell carcinoma (OTSCC). Methods: A retrospective series of cT2-T3 OTSCC treated with upfront CTS at our Department from 2010 to 2021 was evaluated. Radiological and pathological DOI and TDFM were correlated. The main outcomes were overall (OS) and loco-regional recurrence free survival (LRRFS). The linear relationship between DOI and TDFM with 2-year OS and LRRFS was tested. Survival estimates were obtained by the Kaplan-Meier method. Univariate analysis was performed for variables of interest, and results expressed in terms of hazard ratios and 95% confidence intervals. Results: A total of 64 patients underwent CTS and neck dissection. No significant difference was found between pathological (pDOI) and radiological DOI (rDOI) (p = 0.321) or between pathological (pTDFM) and radiological TDFM (p = 0.435). Two- and 5-year OS and LRRFS were 85.7% and 70.4%, 84.3% and 76.1%, respectively. A linear and significant relationship with OS (p = 0.020) and LRRFS (p = 0.013) was found for pDOI; although linear, the relationship between pTDFM was not statistically significant for either survival outcomes. Once categorized, the ideal cut-off for pDOI according to OS was set at 10 mm (p = 0.023). Conclusion: In patients undergoing CTS for primary OTSCC, magnetic resonance-derived rDOI represents an accurate estimate of pDOI, In contrast, TDFM was not associated with OS suggesting that the median raphe is a safe deep margin for CTS. protocol n.: BS/231,009 retrospectively registered.