Lymphadenectomy for lung carcinoids: Which factors may predict nodal upstaging? A multi centric, retrospective study

Objective To investigate risk factors for nodal upstaging in patients with lung carcinoids and to understand which type of lymphadenectomy is most appropriate. Methods Data regarding patients with lung carcinoids, who underwent surgical resection and lymphadenectomy in five institutions from January 1, 2005 to December 31, 2019, were collected and retrospectively analyzed. Clinical and pathological tumor characteristics were correlated to analyze lymph node upstaging. Results The analysis was conducted on 283 patients. Pathology showed 230 typical and 53 atypical carcinoids. Nodal and mediastinal upstaging occurred in 33 (11.6%) and 16 (5.6%) patients, respectively. At the univariable analysis, nodal upstaging was significantly correlated with central location (p = 0.003), atypical histology (p < 0.001), pT dimension (p = 0.004), and advanced age (p = 0.043). The multivariable analysis confirmed atypical histology (odds ratio [OR]: 11.030; 95% confidence interval [CI]: 4.837-25.153, p < 0.001) and central location (OR: 3.295; 95% CI: 1.440-7.540, p = 0.005) as independent prognostic factors for nodal upstaging. Atypical histology (p < 0.001), pT dimension (p = 0.036), number of harvested lymph node stations (p = 0.047), and type of lymphadenectomy (p < 0.001) correlated significantly with mediastinal upstaging. The multivariable analysis confirmed atypical histology (OR: 5.408; 95% CI: 1.391-21.020, p = 0.015) and pT (OR: 1.052; 95% CI: 1.021-1.084, p = 0.001) as independent prognostic factors. Conclusion Atypical histology, dimension, and central location are associated with a high-risk for occult hilo-mediastinal metastases, and mediastinal radical dissection may predict nodal upstaging. Thus, we suggest radical mediastinal lymph node dissection in high-risk tumors, reserving sampling, or lobe-specific dissection in peripheral, small typical carcinoids.