TX Primary tumour cannot be assessed, or tumour proven by the presence of malignant cells in sputum or bronchial washings but not visualised by imaging or bronchoscopy. Most pleural effusions associated with lung cancer are due to tumour. However, there are a few patients in whom multiple cytopathology examinations of pleural fluid show no tumour. In these cases, the fluid is non bloody and is not an exudate. When these elements and clinical judgement dictate that the effusion is not related to the tumour, the effusion is not related to the tumour, the effusion should be excluded as a staging element and the patient s disease should be staged T1, T2 or T3.
Pericardial effusion is classified according to the same rules.
There are four stages, each corresponding to one or more TNM classification. Stage 1 reflecting the best prognosis and stage IV the worst. Limited disease is defined as disease confined to one hemithorax with or without ipsilateral mediastinal or supraclavicular lymphadenopathy, while extensive disease covers any disease spread outside this defined area. 56 Recently patients with contralateral mediastinal and supraclavicular nodes and ipsilateral pleural effusion have been included in the limited disease category. The categories of staging indicate prognosis and treatment options as outlined in the Management section below.