Locoregional Recurrence via Mucus-Mediated Extension Following Lung Resection for Mucinous Tumors

Background: Clinically, locoregional recurrences following mucinous tumor resection are often experienced. However, it is unclear whether mucinous tumors directly affect local recurrence or not, and if so, what the mechanism is. Therefore, we investigated whether mucinous tumors are associated with locoregional recurrence after pulmonary resection and whether mucus extension is a risk factor for locoregional recurrence. Methods The data of 90 patients who underwent pulmonary resection for metastases were reviewed. If mucus was partially or wholly present in the tumor based on macro- or microscopic identification, we assigned the tumor as mucinous. In mucinous tumors, if mucus was identified within the air spaces in the normal lung parenchyma, beyond the edge of the tumor, we assigned the tumor as positive for “mucus extension.” Results The 5-year cumulative incidence of locoregional recurrence in patients with mucinous tumors was 80.3%, which was significantly higher than the 15.5% observed in patients with non-mucinous tumors. Within the mucinous tumor, presence of mucus extension beyond the tumor edge was an independent risk factor for locoregional recurrence after pulmonary resection (hazard ratio, 8.08; P  = 0.049). Conclusion During the resection of mucinous cancer, surgeons should maintain sufficient distance from the tumor edge to prevent locoregional recurrences.