This is the first study to evaluate the feasibility of mediastinal lymph node dissection (MLND) based on sentinel lymph node (SLN) status during pulmonary metastasectomy. A total of 22 patients (16 men, 6 women; age 63.3 ± 7.01 years) who were candidates for metastasectomy through segmentectomy or lobectomy with MLND owing to cancers metastatic to the lung were enrolled in this study. Radiotracer was administered at the peritumoral region before surgery or soon after initiating surgery. During the operation, the radioactivity of the lymph nodes (ex vivo) was counted with a handheld gamma probe after MLND. Lobectomy was performed in 17 patients, and segmentectomy, in 5 patients. The number of dissected lymph nodes per patient was 14.4 ± 8.69 (range, 5-36). In all patients, the SLN could be detected, and the number of SLNs identified was 2.0 ± 1.15 (range, 1-5) per patient. Lymph node metastasis was identified in 3 of the 22 patients (13.6%), and none of the 3 patients with N1 or N2 disease had false-negative SLNs. SLN identification might be an indicator of whether or not MLND should be performed during pulmonary metastasectomy. However, further large-volume and multi-institutional studies are needed.
Keywords: Cancers metastatic to the lung; Mediastinal lymph node dissection; Metastasectomy.