Purpose: To determine the value of computed tomographic (CT) scans in the staging of asymptomatic melanoma patients who presented with or developed local-regional disease as the first site of recurrence and had both a normal chest radiograph and serum lactate dehydrogenase (LDH) level.
Patients and methods: The records of 99 patients with local-regional disease were reviewed. Of these, 89 met the study criteria and are the subjects of this analysis. Radiologic findings were categorized into the following four groups: (1) true-positive (TP), when the scan identified either regional or distant disease that was not appreciated on physical examination; (2) false-positive (FP), when the scan showed a radiologic abnormality that either did not change for at least 6 months or was proven to be histologically benign; (3) false-negative (FN), when a patient had symptoms suggestive of or suspicious for metastases and was subsequently found to have metastases, but all imaging studies were nondiagnostic; and (4) true-negative (TN), when all imaging studies were negative for metastases in an asymptomatic patient.
Results: Findings on CT scan were TP for six patients (7%), FP for 20 (22%), and TN for 63 (71%). Of the six patients with TP findings, CT of the chest identified disease that was not visible on chest radiograph in only one and CT of the abdomen or pelvis showed metastases in five. CT or magnetic resonance imaging (MRI) of the brain showed no evidence of brain metastases in any patient, although it showed asymptomatic skull metastases in one patient. The most common FP findings were hypodense hepatic lesions and noncalcified lung nodules.
Conclusion: TP findings are observed in approximately 7% of patients with local-regional disease, which indicates a low yield but definite usefulness of CT scans in this subset of patients. Because FP are more common than TP findings, histologic diagnosis of recurrence is advisable. CT scan or MRI of the brain is not necessary in asymptomatic patients. CT of the chest adds little to a chest radiograph. In light of today's more cost-conscious health-care environment, our results are of practical importance.