[Value of mediastinoscopy in the preoperative evaluation of non-small cell lung cancer].

Mediastinoscopy is the most reliable examination to determine the presence or absence of lymph node metastases in the preoperative evaluation of lung cancer extension. It is performed either by the cervical route to explore the peritracheobronchial spaces, or by the anterior route to explore the subaortic and anterior mediastinal spaces. It is carried out immediately before thoracotomy, and the rapid frozen section examination of the lymph nodes is accurate enough to decide whether or not resection should be attempted. When mediastinoscopy detects lymph node metastases that are contralateral to the tumour, resection is contra-indicated in view of its poor prognosis. When the metastases are ipsilateral to the tumour, lie low in the mediastinum and are contained in the lymph node capsule, resection is justified since a 5-year old survival can be obtained in almost 10% of the cases. Mediastinoscopy avoids many exploratory thoracotomies. Patients whose cancer is resectable but in whom resection is contra-indicated by this examination have statistically no chance of surviving.