The role of segmental nodes in the pathological staging of non-small cell lung cancer

Background: Segmental nodes are not examined routinely in current clinical practice for lung cancer, the role of segmental nodes in pathological staging of non-small cell lung cancer after radical resection was investigated. Methods: A total of 113 consecutive non-small cell lung cancer patients who underwent radical resection between June 2009 and December 2011 were retrospectively reviewed. All the operations were performed by the same group of surgeons. N2 nodes, hilar nodes, interlobar nodes and some lobar nodes were collected during surgery. The removed lung lobes were dissected routinely along lobar and segmental bronchi to collect lobar nodes and segmental nodes. The collected lymph nodes were separately labeled for histological examination. Results: The detection rates of hilar nodes, interlobar nodes, lobar nodes and segmental nodes were 61.1%, 85.0%, 75.2% and 80.5%, respectively. The metastasis rates of hilar nodes, interlobar nodes, lobar nodes and segmental nodes were 5.3%, 10.5%, 16.8% and 14.2%, respectively. There were 68 cases of N0 disease, 16 cases of N1 disease and 29 cases of N2 disease. If an analysis of segmental lymph nodes had been omitted, six patients (37.5% of N1 disease) would have been down-staged to N0, and two cases of multiple-zone N1 disease would have been misdiagnosed as single-zone N1 disease, one patient would have been misdiagnosed as N2 disease with skip metastases. Conclusion: Segmental nodes play an important role in the accurate staging of non-small cell lung cancer, and routinely dissecting the segmental bronchi to collect the lymph nodes is feasible and may be necessary.