Subcategorization of Resectable Non-Small Cell Lung Cancer Involving Neighboring Structures

Background Although the prognoses of patients with resectable lung cancer involving neighboring structures vary, the current tumor-nodes-metastasis (TNM) classification system does not elucidate criteria for tumor subcategorization. Methods We studied 196 consecutive patients who underwent resection of non-small cell lung cancer involving neighboring structures at the Aichi Cancer Center Hospital and were diagnosed as pathologic T3 diseases using the current staging system. Tumors were divided into six groups based on the involved neighboring structures: parietal or mediastinal pleura, subpleural soft tissue, ribs, main bronchus, pericardium, and diaphragm. Results The overall 5-year survival rate was 39.8%. The survival rates for the six groups were: pleura (n = 62), 54.8%; subpleural soft tissue (n = 50), 30.0%; rib (n = 25), 24.0%; main bronchus (n = 33), 48.5%; pericardium (n = 14), 21.4%; and diaphragm (n = 12), 33.3%. The combined pleura and bronchus groups (n = 95) demonstrated significantly better survival outcome than the other groups (n = 101): 52.6% and 27.7%, respectively (p = 0.0002). Furthermore, among 108 patients with pT3N0 (stage IIB) disease, the prognostic difference between the pleura and bronchus groups (n = 50) and the other groups (n = 58) was significant: 64.0% and 25.9%, respectively (p < 0.0001). Similar results were confirmed in patients with complete resection (n = 159). Conclusions Subcategorization of resectable lung cancer involving neighboring structures resulted in tumor groups infiltrating pleura or main bronchus, and those involving subpleural structures, pericardium, or diaphragm.