Staging procedures are important in distinguishing patients who have disease limited to their thorax from those who have distant metastases. Determining the stage of cancer by nonsurgical means allows a better assessment of prognosis and identifies sites of tumor that can be evaluated for response. Also, the choice of treatment is usually influenced by stage, particularly when chest radiation therapy or surgical excision is added to chemotherapy for patients with limited-stage disease. Staging procedures commonly used to document distant metastases include bone marrow examination, computed tomographic (CT) or magnetic resonance imaging scans of the brain, CT scans of the chest and the abdomen, and radionuclide bone scans.

Because occult or overt metastatic disease is present at diagnosis in most patients, survival is usually not affected by small differences in the amount of locoregional tumor involvement. The detailed TNM staging system developed for lung cancer by the American Joint Committee on Cancer is not commonly employed in patients with small cell lung cancer (SCLC). (Refer to the PDQ summary on Non-Small Cell Lung Cancer Treatment ¹ for more information.) A simple two-stage system developed by the Veterans Administration Lung Cancer Study Group is more commonly used for staging SCLC patients.

Limited-stage disease

Limited-stage SCLC means tumor confined to the hemithorax of origin, the mediastinum, and the supraclavicular nodes, which can be encompassed within a tolerable radiation therapy port. No universally accepted definition of this term is available, and patients with pleural effusion, massive pulmonary tumor, and contralateral supraclavicular nodes have been both included within and excluded from limited stage by various groups.

Extensive-stage disease

Extensive-stage SCLC means tumor that is too widespread to be included within the definition of limited-stage disease above. Patients with distant metastases (M1) are always considered to have extensive-stage disease.[1,2]

References

1. Ihde D, Souhami B, Comis R, et al.: Small cell lung cancer. Lung Cancer 17 (Suppl 1): S19-21, 1997.  [PUBMED Abstract]
   
   
2. Mountain CF: Revisions in the International System for Staging Lung Cancer. Chest 111 (6): 1710-7, 1997.  [PUBMED Abstract]