Effects of tamoxifen and toremifene on urinary excretion of pyridinoline and deoxypyridinoline and bone density in postmenopausal patients with breast cancer
Mb. Marttunen et al., Effects of tamoxifen and toremifene on urinary excretion of pyridinoline and deoxypyridinoline and bone density in postmenopausal patients with breast cancer, CALCIF TIS, 65(5), 1999, pp. 365-368
Tamoxifen and toremifene are two mostly used antiestrogens in the treatment
of breast cancer. To compare their effect on bone in postmenopausal breast
cancer patients we measured the urinary output of two bone resorption mark
ers, pyridinoline (Pyr) and deoxypyridinoline (Dpyr) as well as bone densit
y (BMD) in 30 breast cancer patients using either tamoxifen (20 mg/day, n =
15) or toremifene (40 mg/day, n = 15) as adjuvant treatment of stage II br
east cancer for 1 year. The urinary output of Pyr and Dpyr were assessed be
fore and after 6 and 12 months of the antiestrogen regimen. Lumbar and femo
ral BMD were measured by dual energy X-ray absorptiometry (DXA) before and
after 12 months of treatment. Both tamoxifen and toremifene were associated
with significant decreases in Pyr (mean fall 19.6% and 12.6%, respectively
) and Dpyr (mean fall 21.6% and 15.5%, respectively) at 6 months. After 12
months' treatment, Pyr decreased by 30.8% and Dpyr by 21.2% in women using
tamoxifen and significantly less in women using toremifene (10.1% and 4.9%,
respectively). BMD in the lumbar spine decreased by 1.8% in the toremifene
group but increased by 0.4% in the tamoxifen group; in the proximal femur,
BMD increased slightly during both tamoxifen and toremifene treatment in a
ll sites measured. Individual changes in Pyr and Dpyr at 6 months showed no
significant relation to the change in BMD at 12 months. We conclude that t
amoxifen (20 mg/day) and toremifene (40 mg/day) reduce the bone resorption
similarly, and this can be detected by falls in urinary output of Pyr and D
pyr at 6 months of treatment.