ROLE OF BONE SCANNING IN DETECTION OF SUBCLINICAL BONE METASTASIS IN NASOPHARYNGEAL CARCINOMA

One hundred thirty-two new patients with nasopharyngeal carcinoma and no evidence of distant metastases were evaluated for bone metastases with bone scanning. Forty-four patients had abnormal hypercaptation. These abnormal findings were considered related to benign diseases in 39 patients after correlating clinical examinations and skeletal radiographs. The remaining five patients had positive bone scanning which was suggestive of bone metastasis. There were 13 patients who developed symptomatic bone metastases over a follow-up period of 0.2-41 months. In three of thses, the bone metastases corresponded to the sites of abnormal hypercaptation in the initial positive bone scannings. In view of the low sensitivity and specificity of bone scanning in this setting, routine bone scanning for staging nasopharyngeal carcinoma is not recommended. But in the research setting, baseline scanning is useful to make subsequent scanning more valuable, and it reduces false-positive results.