Pathologic NO status in pulmonary adenocarcinoma is predictable by combining serum carcinoembryonic antigen level and computed tomographic findings

Objectives. It is not clear whether lymphadenectomy has therapeutic benefit in non-small cell lung, cancer management. To avoid unnecessary lymphadene ctomy, we attempted to identify clinical or radiologic predictors of pathol ogic NO disease in patients with peripheral adenocarcinoma. Methods: From August 1992 through April 1997, 269 consecutive patients with peripheral adenocarcinoma who underwent major lung resection and systemati c lymph node dissection were enrolled in this study. We reviewed their cont rast-enhancement computed tomographic scans and recorded the maximum dimens ion of tumors both on pulmonary (pDmax) and on mediastinal (mDmax) window s etting images, the largest dimension perpendicular to the maximum axis on b oth pulmonary (pDperp) and mediastinal (mDperp) window setting images, and the size of all detectable hilar-mediastinal lymph nodes. We defined a new radiologic parameter, tumor shadow disappearance rate (TDR), which is calcu lated with the following formula: TDR = 1 - mDmax x mDperp/pDmax x pDperp. Results: In multivariable analysis a lower serum carcinoembryonic antigen l evel and a higher tumor shadow disappearance rate were significant predicto rs of pathologic NO disease. Lymph node size on computed tomographic scanni ng was not a significant predictor. Among 59 patients with a normal preoper ative carcinoembryonic antigen level and a tumor shadow disappearance rate of 0.8 or more, 58 (98%) patients had pathologic N0 disease, and the other patient had pathologic N1 disease. Conclusions. Mediastinal lymph node involvement was not found in patients w ith a normal preoperative serum carcinoembryonic antigen level and a tumor shadow disappearance rate 0.8 or more. The patients who meet these criteria may be successfully managed with major lung resection without systematic m ediastinal lymphadenectomy.