Aggressive surgical intervention in N2 non-small cell cancer of the lung. An aggressive attitude toward surgical treatment was taken in patients with N2 non-small cell lung cancer in the past 10 years. Computed tomographic scanning was employed in the diagnosis of N2 disease, and had a true-positive rate of 57%. Among patients with N2 disease detected by computed tomographic scanning, surgical intervention was attempted except for those with unresectable disease. Of 190 patients with clinical N2 disease, 115 underwent surgical exploration: 9 patients had only an exploratory thoracotomy, 53 patients underwent a curative operation, and 53 had a noncurative operation. The overall 5-year survival rate of these patients was 16% and that of curatively resected patients was 20%. There were 47 patients whose N2 disease was not recognized before operation. The 5-year survival rate of this group was 20% overall and 33% in curatively resected cases. The overall 5-year survival rate of patients with N2 disease who underwent resection (106 with clinical N2 disease and 47 with clinically unrecognized N2 disease) was 17%, and that of the 84 patients undergoing curative operations was 24%. An aggressive attitude toward surgical intervention can be advocated for patients with N2 disease on the basis of our present results. 