Preoperative serum carcinoembryonic antigen level and computed tomographic findings are predictors of pathological N0 in clinical stage IB lung adenocarcinoma

Background: The standard intervention for resectable non-small cell lung cancer (NSCLC) has been lobectomy and systematic lymph node dissection. Recently, limited surgery with/without lymphadenectomy has been repeatedly evaluated in clinical stage IA NSCLC, and a clinical trial of wedge resection without lymph node dissection is now ongoing in Japan for clinical T1aN0M0 sub-solid tumors, organized by the Japan Clinical Oncology Group. However, few reports have analyzed the validity of limited surgery in clinical stage IB (cIB) NSCLC. We reviewed cIB pulmonary adenocarcinoma patients in an attempt to identify clinical and radiologic predictors of pathological N0 (pN0) disease. Methods: From 2002 through 2009, 224 consecutive patients with cIB adenocarcinoma who underwent complete resection with systematic lymph node dissection were enrolled. We reviewed their preoperative clinical data and computed tomographic scans, and evaluated the correlations between nodal involvement and the following factors: age, gender, smoking history, preoperative serum carcinoembryonic antigen (CEA) level (normal range: ≤ 5.0 ng/mL), and tumor disappearance ratio (TDR: 1- DM/DL; DM: maximum tumor diameter on mediastinal settings, DL: maximum tumor diameter on lung settings). Univariate and multivariate analyses were performed using logistic regression models. Results: There were 115 men and 109 women. The median age was 67 years (range: 37 - 85). There were 164 pN0 patients and 60 pN1-2 patients. In univariate analysis, a lower preoperative CEA level and a higher TDR were significant predictors of pN0 disease. In multivariate analysis, preoperative CEA level (OR: 0.032, 95%CI: 0.002 - 0.340) and TDR (49.32, 10.94 - 285.5) were significant independent predictors of pN0 disease. All of the 18 patients with a ≥ 0.9 had pN0 disease. Among 45 patients with a TDR ≥ 0.7 (pN0/pN1: 44/1), 33 patients with a normal preoperative CEA level had pN0 disease. Conclusion: Lymph node metastasis was not observed in cIB patients with a TDR ≥ 0.9 or in those with a normal preoperative serum CEA level and TDR ≥ 0.7. These patients may be successfully managed without systematic lymph node dissection.