VALIDITY OF ENLARGED MEDIASTINAL NODES AS MARKERS OF INVOLVEMENT BY NON-SMALL-CELL LUNG-CANCER

To assess the validity of enlarged mediastinal nodes as markers of involvement for staging in non-small cell lung cancer, we studied the records of 167 consecutive patients who underwent thoracotomy for this disease in the last 4 yr in our center. Careful search for both hilar (N1) and ipsilateral mediastinal nodes (N2) was done in every case. All nodes found at thoracotomy (regardless of their size) were either removed or sampled and then sent to the pathology department for examination. We found enlarged nodes (larger than 10 mm) in 131 of the 167 patients included in the study (72%). Of these patients, 58 had enlarged nodes at the hilar level (presumably N1 disease, 38%), and 73 were considered as presumably N2 at thoracotomy, before pathologic examination (62%). Only 12 of 58 patients with presumably N1 disease had true neoplastic involvement at this level (21%), whereas there was true N2 disease in only 18 of 73 patients with enlarged mediastinal nodes (25%). The positive predictive value for N2 in epidermoid carcinoma was 23%, and it was even lower with adenocarcinoma (18%). We conclude that open surgery with careful sampling is the method of choice for evaluation of mediastinal nodes in non-small cell lung cancer if evidence of malignant involvement cannot be proven histologically before thoracotomy.