VAT was used to assess direct tumour invasion of adjacent organs in 17 patients (mediastinal invasion in 14 and chest wall invasion in 3 patients). In 4 patients with limited respiratory reserve, VAT confirmed the need only for lobectomy prior to thoracotomy. Mediastinal lymph node biopsy was performed in 5 patients with significant (>1.5 cm) lymphadenopathy on CT scan. VAT was also used to assess bilateral lesions in 4 patients with suspected synchronous tumours