Intravenous bisphosphonate therapy does not acutely alter nuclear bone scan results

Theoretically, the bisphosphonates used to treat metastatic bone disease could influence the results of nuclear bone scans which use the structurally similar technetium 99m methylene diphosphonate (99mTc MDP). A prospective clinical study was designed to explore this hypothesis.

Patients with metastatic breast cancer receiving intravenous bisphosphonate (IVBP) therapy who had > or =3 osseous lesions on nuclear bone scan were eligible. A baseline bone scan (number 1) was performed as clinically indicated and IVBP with zoledronic acid was administered within 72 hours. A second bone scan (number 2) was performed within 72 hours of zoledronic acid dosing. Both bone scans were reviewed in a blinded fashion and assessed for changes in the number and intensity of osseous lesions. Ten patients were planned to yield at least 30 lesions.

Ten patients were enrolled. One patient withdrew consent and 1 was excluded due to protocol deviation. Among the 8 patients were 163 assessable osseous lesions. The median time from bone scan number 1 to IVBP was 1 day (range, 1-2 days). The median time from IVBP to bone scan number 2 was 2 days (range, 1-3 days). The paired imaging showed no changes in the total number of bone metastases. One hundred sixty-one lesions were identical in both scans; in 1 patient there were 2 lesions that were discordant, one more intense, the other less intense.

These data do not support the hypothesis that IVBP therapy interferes with bone scan results.