Bone scans with one or two new abnormalities in cancer patients with no known metastases: reliability of interpretation of initial correlative radiographs

To determine the reliability of radiographs obtained for correlation with bone scans showing one or two new abnormalities in cancer patients without known metastases, a retrospective study of 306 scans showing such lesions was performed. Overall, 14% of the lesions proved to be malignant. The initial radiographic interpretation was normal for 43% of the new bone scan lesions; 17% of these lesions were metastases. A benign process was identified on radiographs for 38% of the abnormalities; only one (1%) was a metastasis. Twelve percent of new bone scan lesions correlated with radiographic abnormalities considered either suggestive of or consistent with metastasis, of which 24% and 71%, respectively, proved to be metastases. In cancer patients with one or two new bone scan abnormalities, correlative radiographs showing a benign abnormality are reliable. However, if the radiographs are either normal or show findings considered suggestive of or consistent with metastasis, further evaluation or follow-up is warranted.