Clinical studies on the detection of bone metastasis in lung cancer by bone scintigraphy

The purpose of this study is to evaluate the clinical usefulness of bone scan to detect bone metastasis in lung cancer. Two hundred and forty-eight scans were performed on 148 patients using Tc-99m EHDP or Tc-99m MDP. Out of 74 patients with abnormal accumulations, 44 were attributed to bone metastasis, 23 to non-tumor conditions on bone, and 7 were suspected of bone metastasis but could not be confirmed. The bone metastasis wad detected in 12 (17.4%) of 69 patients who were scanned before therapy, and in 15 (37.5%) of 40 patients who died within 2 months after bone scan. Among 58 patients whose clinical stage was classified as I, II, and III before bone scan, 6 were found to be in stage IV due to their positive scan. Forty-eight patients whose scans before therapy were negative, were followed up with the scan. During the course 8 cases turned positive, and in 7 of them the interval from the first negative to positive scan was shorter than 16 months. Two of them showed no abnormal findings on X-ray survey but one revealed metastasis by aspiration cytological examination of bone and the other by follow-up X-ray surveys. Out of 43 patients who were detected bone metastasis with bone scan, 28 died within 6 months and the additional 11 died within a year after the detection. In conclusion, the bone scan is found to be useful to decide the initial clinical stage of the patients with lung cancer, to predict their prognosis and to follow-up them. (author)