Restaging after induction therapy for non-small cell lung cancer.

One of the advantages of the TNM classification of malignant tumours is that it does not require a minimum number of explorations. This allows the different specialists who are involved in the management of lung cancer patients to assess the anatomical extension of the disease regardless of the medical setting in which they work. A drawback of this universal applicability of the TNM classification is that it renders series of patients whose tumours are assessed with various degrees of intensity, depending on the availability or the utilization of the different staging explorations. In order to know the degree of intensity of the staging process and the validity of the classification, the Union Internationale Contre le Cancer (UICC) recommends to use the so called certainty factor (C factor) (Table 1). The highest certainty in the clinical classification of untreated tumours, in the classification of recurrent tumours, and in the classification of tumours treated with induction therapy is obtained by the surgical explorations grouped in certainty factor 3 (C3). These explorations, namely, mediastinoscopy, parasternal mediastinotomy, pericardioscopy and thoracoscopy, among others, allow the surgeon to obtain tissue diagnosis of both the extension of the primary tumour and of its lymphatic spread.