Are oral bisphosphonates effective in improving lumbar bone mineral density in breast cancer survivors with osteopenia or osteoporosis?
OBJECTIVE
Breast cancer survivors with osteoporosis or osteopenia are commonly encountered in primary care and gynaecology practices. Our objective was to determine whether treatment with oral bisphosphonates (alendronate or cyclic etidronate) was more effective than calcium with vitamin D in improving lumbar spine bone mineral density (BMD) within one year in breast cancer survivors.


METHODS
Breast cancer survivors with at least one year of clinical follow-up were identified from the prospective observational Canadian Database of Osteoporosis and Osteopenia (CANDOO). Analysis of covariance was used to examine the effects of bisphosphonate therapy on change in lumbar spine BMD at one year compared with the effects of calcium with vitamin D (analysis adjusted for baseline L2-L4 BMD, current tamoxifen use, number of prevalent vertebral fractures [VFs], and time since diagnosis of breast cancer, and age).


RESULTS
Eighteen patients took calcium and vitamin D, 25 took cyclic etidronate, and 27 took oral alendronate. Adjusted one-year BMD increases for alendronate and cyclic etidronate compared to calcium and vitamin D were as follows: alendronate 4.53% (95% confidence interval [CI] 1.26%, 7.81%, P = 0.008), and cyclic etidronate 1.85% (-1.55%, 5.25%, P = 0.280). BMD increases were significantly greater in patients with prevalent VF compared to those without VF (P = 0.025). In contrast, time since diagnosis of breast cancer was significantly associated with a decrease in BMD (P = 0.002). We were unable to detect any effect of current tamoxifen use, baseline lumbar spine BMD, or age on changes in BMD at one year.


CONCLUSIONS
Treatment with alendronate was associated with significantly greater improvements in lumbar spine BMD within one year in breast cancer survivors when compared with treatment with cyclic etidronate or calcium and vitamin D.
Sawka
Anna M
AM
Department of Medicine, St. Joseph's Healthcare and McMaster University, Hamilton ON.
Ioannidis
George
G
Papaioannou
Alexandra
A
Thabane
Lehana
L
Olszynski
Wojciech P
WP
Brown
Jacques P
JP
Hanley
David A
DA
Murray
Tim M
TM
Josse
Robert G
RG
Sebaldt
Rolf J
RJ
Petrie
Annie
A
Tenenhouse
Alan
A
Goldsmith
Charlie H
CH
Boulos
Pauline
P
Kouroukis
Tom
T
Adachi
Jonathan D
JD
D000368:Aged; D019386:Alendronate / Q000627:therapeutic use*; D000704:Analysis of Variance; D015519:Bone Density / Q000187:drug effects*; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D001851:Bone Diseases, Metabolic / Q000139:chemically induced / Q000453:epidemiology / Q000517:prevention & control*; D001943:Breast Neoplasms / Q000150:complications / Q000628:therapy; D002118:Calcium / Q000627:therapeutic use; D012968:Etidronic Acid / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008875:Middle Aged; D010024:Osteoporosis / Q000139:chemically induced / Q000453:epidemiology / Q000517:prevention & control*; D012307:Risk Factors; D016103:Spinal Fractures / Q000139:chemically induced / Q000453:epidemiology / Q000517:prevention & control; D016896:Treatment Outcome; D014807:Vitamin D / Q000627:therapeutic use
D050071:Bone Density Conservation Agents; D014807:Vitamin D; D012968:Etidronic Acid; D002118:Calcium; D019386:Alendronate