Peripheral small-sized (2 cm or less) non-small cell lung cancer with mediastinal lymph node metastasis; clinicopathologic features and patterns of nodal spread.

Abstract

Objective: The diagnosis of small-sized (2 cm or less) non-small cell lung cancer (NSCLC) has increased with the development of computed tomography (CT), whereas unexpected extensive multiple-level mediastinal involvement has been occasionally detected in this small-sized lung cancer. To establish the optimal surgical strategy, we retrospectively analyzed the clinicopathologic features, efficacy of preoperative investigations and lobe specific patterns of nodal spread in small-sized NSCLC with mediastinal involvement. Methods: Among 1550 resected lung cancer cases between 1981 and 2000, 267 (17.2%) had peripheral small-sized NSCLC. Of these, 29 patients (10.8%) with mediastinal lymph node involvement who underwent pulmonary resection and systematic nodal dissection were reviewed. Results: Among 29 patients, 27 patients (93.1%) were adenocarcinoma, and 51.7% (15/29) showed no lymph node enlargement on CT (cN0). Surgical pathology revealed multiple-level mediastinal involvement in 65.5% (19/29) of all patients and 60.0% (9/15) of cN0 patients. All of right upper lobe tumors (n=11) showed multiple-level involvement. Thallium-201 single photon emission computed tomography (201Tl-SPECT) was positive for increased focal uptake in the mediastinum in 72.7% (8/11) of patients. Conclusions: The vast majority of cases were adenocarcinoma, and two thirds of them showed multiple-level mediastinal involvement, even in cN0 patients. We thus recommend to perform systematic nodal dissection or meticulous sampling for accurate intrathoracic staging, especially for right upper lobe tumor. 201Tl-SPECT appears to be more sensitive preoperative investigation for mediastinal metastasis compared with CT scan.