Stage IA and IB of the Non-Small Cell Lung Cancer

The illustration shows a tumour of a non-small cell lung cancer (NSCLC), staged IA. The tumour is limited to one lung lobe and has not spread out to surrounding lung structures; lymph nodes are also unaffected.

Stage IB is present if the tumour diameter is >=3 cm, or if the tumour touches the pleura, or when a part of the lung has collapsed due to tumour growth and the gas exchange has ceased. The tumour is, however, as in Stage IA, localised to one site of the lung and there is no lymph node involvement.