The current state of carinal resection and role of minimally invasive techniques

Lung cancer is a leading cause of cancer-related mortality in the United States with over 235,000 new cases in 2021 and nearly 132,000 deaths. Primary malignant tracheal neoplasms are rare tumors with an annual incidence of 0.1/100,000 and account for 0.1% of all cancer deaths (1,2). The most common histological types are squamous cell carcinoma (36–45%) and adenoid cystic carcinoma (31–40%) (3). Surgical resection is generally considered the best curative option for early-stage lung cancer as well as in a reasonable proportion of patients with clinical stage IIIb and stage IV disease (4). Adenoid cystic carcinoma has a tendency for submucosal spread and is associated with microscopically positive margins in 55% of patients (5). Therefore, R0 resection may be difficult to achieve without excessive anastomotic tension. In the surgical treatment of bronchogenic carcinoma, resection of the trachea-bronchial bifurcation is performed in less than 1% of patients with non-small cell lung cancer (NSCLC) and other low-grade neoplasms. Primary tracheal tumors are the main indication for a carinal resection with subsequent reconstruction (6). Carinal resection is a technically challenging procedure. Although it has been performed for over 70 years, only recently have acceptable morbidity and mortality rates been achieved. The 5-year survival rate after carinal resection for bronchogenic carcinoma varies from 21% to 44% and is highly dependent on the stage and the histology: 62% for adenoid cystic carcinoma and 46% for squamous cell carcinoma in N0 disease, 32% in N1, and 12% in N2/N3 disease (7-11). Carinal resection for bronchogenic carcinoma is usually indicated for centrally located tumors within one centimeter of either main bronchi or invading the carina. Carinal resection can either be performed in isolation or be combined with parenchymal resection. The reported mortality for isolated carinal resection ranges from 3% to 12.7% in high volume centers compared to initial reports with 40% mortality rate (8,10,12). Severe complications after carinal resections are mainly attributable to non-cardiogenic pulmonary edema with subsequent acute respiratory distress syndrome (ARDS) as well as anastomotic leak or stenosis, both of which remain a leading cause of postoperative mortality. The reported rate ranges between 2% and 8.5% (8). The incidence of anastomotic complications varies from 11% to 17% (11). The higher morbidity and mortality rates associated with carinal pneumonectomy, compared to isolated procedure, are due to the higher incidence (up to 14% of cases) of post pneumonectomy pulmonary edema and ARDS (11). Sleeve resection of the bronchus, the pulmonary artery or both provides complete tumor resection while avoiding pneumonectomy in centrally-located malignancies (13). In light of the above, accurate staging is crucial in the preoperative setting. In addition, preoperative evaluation should include a full staging workup and careful physiologic assessment. Thorough bronchoscopy with multiple biopsies allow adequate assessment of the extent of neoplastic infiltration, which must be less than 2.0 cm of the distal Editorial Commentary