RANDOMIZED TRIAL OF PAMIDRONATE IN PATIENTS WITH THYROID-CANCER - BONE-DENSITY IS NOT REDUCED BY SUPPRESSIVE DOSES OF THYROXINE, BUT IS INCREASED BY CYCLIC INTRAVENOUS PAMIDRONATE

Patients taking suppressive doses of T-4 are thought to have accelerat ed bone loss and increased risk of osteoporosis. We therefore randomiz e 55 patients taking suppressive doses of T-4 to treatment with pamidr onate (APD) 30 mg iv every 3 months for 2 yr (APD/T-4), or placebo (pl acebo/T-4). Patients had measurements of bone mineral density (BMD) of the spine, hip, radius, and total body every 6 months for 2 yr. There was no significant bone loss at any site in the placebo/T-4 group. Ni nety five percent confidence intervals excluded a rate of bone loss >0 .89%/yr for the spine and >0.31%/yr at the total hip. When men were ex cluded from the analysis, there still was no significant bone loss for the placebo/T-4 group, and confidence intervals did not change. The A PD/T-4 group showed increases in spine (4.3%, P = 0.0001), total hip ( 1.4%, P < 0.05), and trochanteric (3.0%, P = 0.0001) BMDs. In conclusi on, premenopausal women and men on suppressive therapy with T-4 do not lose bone rapidly, and are not at increased risk of developing osteop orosis. A regimen of 30 mg APD given every 3 months for 2 yr causes si gnificant suppression of bone resorption and increases in BMD, and may be an acceptable alternative treatment for osteoporosis in patients wh o cannot tolerate oral bisphosphonates.