T4

Fig. 18b: Computed tomographic scan of the chest at the 3rd thoracic vertebra shows invasion of the left side of the vertebral body and extension of tumor into the intervertebral foramen (white arrow), T4.

Fig. 19: Posterior-anterior chest radiograph showing pleural effusion on the left. Malignant pleural effusion due to the underlying malignant process is classified T4, whether cytology is positive or negative.

A few patients are seen in whom cytopathological examination of pleural fluid on more than one specimen is negative for tumor, the fluid is non-bloody and is not an exudate. If negative cytologies and clinical judgment indicate that the effusion is unrelated to the lung cancer, the effusion is disregarded as a staging element and T1, T2 or T3 as appropriate is assigned.