Abdominal computed tomography in small cell lung cancer: Assessment of extent of disease and response to therapy

Abdominal computed tomography (CT) was performed as part of the initial staging evaluation in 77 patients with small cell carcinoma (SCC) of the lung. CT scans revealed mass lesions in 26 patients (34%). Abnormalities were confined to the liver in 15 patients and to retroperitoneal structures (lymph nodes, adrenal glands, psoas muscle region masses) in eight, and occurred in both areas in three. However, only three of 29 patients otherwise staged as having limited disease (confined to one hemithorax and regional nodes) had evidence of abdominal metastases on CT scan. Most (23/26) positive studies were in patients already known to have more extensive tumor dissemination. In 71 patients with pathologic confirmation of liver status, CT had a sensitivity of 63%, specificity of 91%, and overall accuracy of 85% in assessing the liver. Comparison of radionuclide liver scan findings with hepatic biopsies gave similar results. During therapy, 65 follow‐up CT scans were obtained in 46 patients. Scan abnormalities improved or disappeared in 11/12 cases with tumor response documented in other ways, appeared or worsened in 5/13 cases of tumor progression that was diagnosed by other tests, and only rarely (2/65 scans) improved at the time of documented tumor progression, or vice versa. In only three patients, however, did CT scan provide the sole site of evaluable disease during treatment or detect either the only area of residual disease in a patient in otherwise complete remission or the initial evidence of tumor progression. Although abdominal CT scans in SCC can demonstrate metastatic dissemination not evaluable by other means, they provide relatively little therapeutically relevant information beyond that obtained with standard staging procedures.