Preoperative staging of lung cancer: accuracy of computed tomography versus mediastinoscopy

Forty-four patients coming to surgery for carcinoma of the bronchus underwent preoperative staging of the mediastinum by computed tomography (CT scanning) and surgical exploration of the mediastinum by cervical mediastinoscopy or left anterior mediastinotomy or both. Where mediastinal nodes were affected the sensitivity and specificity of computed tomography was inferior to that of mediastinoscopy (57% and 85% versus 71% and 100%). The sensitivity of computed tomography in predicting mediastinal invasion was superior to that of mediastinoscopy (77% v 46%), especially in the case of lower-lobe tumours (67% v 17%). Mediastinoscopy had the considerable advantage of 100% specificity. In the assessment of hilar lymphadenopathy computed tomography had a sensitivity of 38% and a specificity of 64%. In cases where computed tomography showed a normal mediastinum or enlargement of the hilar glands only, mediastinal exploration conferred no additional information and could have been omitted. A computed tomography scan showing mediastinal abnormality is an indication for mediastinoscopy and not a contraindication to surgery. In 23 patients computed tomography showed some abnormality of the mediastinum, confirmed at mediastinoscopy in 12 cases. The remaining 11 patients underwent thoracotomy, resection being carried out in nine. Postsurgical staging showed that six of these tumours were N0 lesions without invasion; in two further N0 cases there was a minor degree of mediastinal invasion which did not prevent resection, and the remaining tumour was N1 without invasion.