Role of (99m)tc-hexakis-2-methoxy-isobutylisonitrile in the diagnosis and staging of lung cancer.

BACKGROUND: Preliminary studies have shown that (99m)Tc-hexakis-2-methoxyisobutylisonitrile (MIBI) is an interesting tracer for various tumors. The aim of this study was to determine the feasibility of using (99m)Tc-MIBI as a diagnostic and staging procedure for lung cancer.

METHODS: We prospectively compared the results of biopsy with (99m)Tc-MIBI imaging in patients with potentially resectable lung lesions (stages IIIA or lower). In the patients with radiopharmaceutical uptake, the staging provided by CT was compared with that obtained with (99m)Tc-MIBI.

RESULTS: Ninety-nine of the 116 patients examined had lung cancer. For the diagnosis of malignancy, the specificity of (99m)Tc-MIBI was 100%, sensitivity was 89.8%, positive predictive value was 100%, negative predictive value was 62.9%, and accuracy was 91.4%. In the 87 patients with radiopharmaceutical uptake in their lung cancer, the values for the specificity and sensitivity of (99m)Tc-MIBI in the detection of mediastinal lymph node metastases were 100% and 54.5%, respectively. The corresponding values for CT in the same patients were 87.6% and 63.3%, respectively. The difference in specificity is statistically significant (p = 0.011).

CONCLUSIONS: This study demonstrates that (99m)Tc-MIBI provides significant diagnostic and staging information in patients with lung lesions. The high specificity and positive predictive value of (99m)Tc-MIBI suggest that this radiopharmaceutical could be a very useful tool for the diagnosis of lung cancer, especially in consideration of its low costs and wide availability.