Evaluation of 67 Ga citrate and 99m Tc bone scintigraphy at initial examination for primary oral squamous cell...

This study was carried out to evaluate the diagnostic utility of gallium citrate Ga 67 ((67)Ga) and technetium Tc 99m bone scintigraphy as initial screening methods for distant metastasis and synchronous malignancies in patients with oral cancer.

Ga and/or bone scintigraphy was performed for 123 patients with primary squamous cell carcinoma (SCC). Abnormal accumulation sites detected with scintigraphy were reevaluated with radiography or computed tomography. Whether the accumulation sites were metastatic was determined according to the radiographic findings and the later clinical course of the patients.

Ga scintigraphy did not detect distant metastases or 4 synchronous cancers at other sites and provided no useful information on the emergence of delayed pulmonary metastases that developed in 3 cases after a few months. Ga scintigraphy showed an abnormal accumulation in 53% of primary tumors and 25% of metastatic cervical lymph nodes, and the detection of accumulation was closely related to the size of the lesion. Bone scintigraphy showed 1 case (0.9%) with distant metastasis to the vertebra; however, there were numerous false-positive cases that required additional radiographic confirmation.

These results suggested that Ga and bone scintigraphy at the initial examination of patients with primary oral SCC are ineffective for detecting distant metastasis and other malignancies because of the low incidence of these lesions and the diagnostic inaccuracy of scintigraphy.