Prognostic factors and outcomes in minimal access resections of skull base and sinonasal epithelial malignancy

Background: Sinonasal epithelial malignancies are uncommon tumours but represent a challenge to treatment given their close proximity to the orbit, brain and cranial nerves. Traditional external surgical approaches have potential for significant functional and cosmetic morbidity. An endoscopic approach provides the surgeon with good access for tumour removal and enables surveillance postoperatively. This study aimed to assess outcomes of an endoscopic approach to sinonasal epithelial malignancy and evaluate factors that may influence its utility. Methods: A case series was performed involving consecutive patients treated with endoscopic or endoscopic-assisted surgery for epithelial sinonasal malignancy. Stratification included TNM staging, histopathology, surgical approach, margin status, perineural involvement and adjuvant or neoadjuvant therapy. At follow-up, complications, local control, nodal status and evidence of distant metastases were recorded. Statistical analyses to identify risk factors for developing recurrence and survival differences were performed. Results: Thirty-five patients were assessed in this study (59.2 ± 11.4 years, 42.9% female). T stage at presentation was T1 in 11.4%, T2 in 17.1%, T3 in 22.9% and T4 in 48.6%. The 3 and 5 year disease specific survival were 91.3% (SE 5) and 71.1% (SE 10). The only factors to influence survival outcomes were perineural invasion of tumour and positive margins at the time of initial surgery. Large tumours did not limit the utility of an endoscopic approach. Conclusion: Endoscopic approach is a safe and oncologically equitable treatment approach to external approaches in the management of epithelial sinonasal malignancy. As with external approaches, perineural invasion of malignance is a poor prognostic factor.