Diagnostic imaging and staging of primary lung cancer.
Improved diagnostic imaging has the potential to guide the surgeon in choice of invasive procedures required for staging and treatment of lung cancer. In the evaluation of a solitary pulmonary nodule, absence of growth for 2 years or certain typical calcifications are strong evidence of benignity, but we do not advocate following indeterminate nodules without a diagnosis because even small nodules may be carcinomas. In assessing chest wall invasion, computed tomography has no greater predictive value than a history of localized pain. The absence of nodes greater than 1.0 cm in short axis diameter on computed tomograms of the thorax is associated with low risk of tumor in mediastinal nodes, but tissue diagnosis is required for certainty. The finding of nodes larger than 1.0 cm may be useful in guiding the surgeon during staging procedures. Currently, there is no advantage of magnetic resonance imaging over computed tomography in evaluation of mediastinal nodes. Complete history and physical examination with routine serum chemistries will identify patients at high risk for metastases and will guide selection of appropriate special studies. It is emphasized that accurate staging requires histologic diagnosis and that CT and thorough surgical evaluation of the mediastinum are complementary procedures in staging of lung cancer.