Clinical characteristics of a second small nodule(s) associated with cT1-2N0M0 non-small-cell lung cancer.

When a patient with cT1–2N0M0 stage non-small-cell lung cancer (NSCLC) has a second small nodule(s), the treatment plan and prognosis depend largely on whether the nodule is benign or malignant. However, the incidence of malignancy of nodules associated with N0 and M0 NSCLC is unknown. Furthermore, predictive factors of malignancy have not been defined. Thus, we evaluated the nature of nodules that were less than 15 mm in diameter associated with stage T1–2N0M0, and tried to identify clinical and radiologic factors predictive of malignancy. The study population consisted of 39 patients with T1–2N0M0 NSCLC and a second nodule(s) less than 1.5 cm and who had received curative resection. Medical records and radiologic findings, including CT scans of the chest, were retrospectively reviewed. Nodules were finally diagnosed as benign in 85% and malignant in 15%. No significant differences in terms of gender, age, preoperative carcinoembryonic antigen (CEA) level, cell type, pathologic stages, shape, size, location and number of nodules, or the presence of calcification around nodules was observed between benign and malignant groups. We suggest that if primary NSCLC is resectable, an effort should be made to confirm the pathologic diagnosis of nodules. If histologic findings in nodules are not available, surgical resection should be actively considered, especially when nodules < 1.5 cm are associated with N0 or M0 NSCLCs.