Changes in bone mineral density during and after 3 years' use of tamoxifen or toremifene.
OBJECTIVE
To study the effects of tamoxifen and toremifene on bone mineral density (BMD) in postmenopausal women with breast cancer.


METHODS
Seventy patients with stage II-III breast cancer were randomized to start either tamoxifen (n = 36; 20 mg per day) or toremifene (n = 34; 40 mg per day) for 3 years. BMD in the lumbar spine and in the proximal femur was measured by dual-energy X-ray absorptiometry both before and during the treatment and 1 year after the discontinuation of the anti-estrogens.


RESULTS
The baseline BMD measurements were comparable between the groups. In 3 years, lumbar BMD decreased by 1.7% in tamoxifen (P = 0.048) and 3.0% in toremifene (P = 0.001) users (ns between the groups), and femoral neck BMD by 0.9% (P = 0.040) and 1.3% (P = ns), respectively. The use of hormone replacement therapy (HRT) until the diagnosis of breast cancer was associated with decreases in lumbar BMD during anti-estrogen regimen (4% at 3 years) in contrast to unchanged lumbar BMD in women with no previous use of HRT. During the 1st year after the cessation of anti-estrogen, lumbar BMD did not change at all in either group whereas femoral BMD decreased in both the groups at the rate of 1.5-3.2%, as expected.


CONCLUSIONS
We conclude that tamoxifen (20 mg) and toremifene (40 mg) have similar bone-sparing efficacy that in lumbar spine extends up to 1 year after the cessation of these regimens. This effect is not seen in lumbar spine BMD in those postmenopausal women who discontinue HRT at the time of breast cancer diagnosis.
Tiitinen
Aila
A
Department of Obstetrics and Gynecology, Helsinki University Central Hospital, P.O. Box 140, 00029 Hus, Finland.
Nikander
Eini
E
Hietanen
Päivi
P
Metsä-Heikkilä
Merja
M
Ylikorkala
Olavi
O
D015502:Absorptiometry, Photon; D000704:Analysis of Variance; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage*; D015519:Bone Density / Q000187:drug effects*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy; D017024:Chemotherapy, Adjuvant; D005260:Female; D005272:Femur Neck / Q000187:drug effects / Q000502:physiology; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000187:drug effects / Q000502:physiology; D008875:Middle Aged; D018714:Radiotherapy, Adjuvant; D020845:Selective Estrogen Receptor Modulators / Q000008:administration & dosage*; D013629:Tamoxifen / Q000008:administration & dosage*; D017312:Toremifene / Q000008:administration & dosage*
D018931:Antineoplastic Agents, Hormonal; D020845:Selective Estrogen Receptor Modulators; D013629:Tamoxifen; D017312:Toremifene