Effect of anastrozole on bone mineral density after one year of tr

[Guest guest]

Boy, wait 'til the side-effects come.

" Third generation aromatase inhibitors " shouldn't have too many, SHOULD

they?

 

RB, The only " safe " drug is a NEW one

 

" I just wanted you to know "

 

[in cancercure group]

Posted by: " szukidavis " szukidavis   sheldavis

Mon Dec 24, 2007 12:53 pm (PST)

 

Effect of anastrozole on bone mineral density after one year of

treatment:

results from bone sub-study of the International Breast Cancer

Intervention

Study (IBIS-II).

 

http://www.abstracts2view.com/sabcs/view.php?nu=SABCS07L_270

 

Singh S, Cuzick J, Edwards R, Blake G, Truscott J, Coleman J, Eastell R,

Howell A. Wolfson Institute of Preventive Medicine, London; Kings

College School

of Medicine, London; University of Leeds, United Kingdom; University of

Newcastle, Australia; Christie Hospital, Manchester, United Kingdom;

Northern General Hospital, Sheffield, United Kingdom

 

Background: The third generation aromatase inhibitors have been shown to

reduce bone mineral density when compared with tamoxifen in the

advanced, adjuvant and neoadjuvant settings in women with early breast

cancer. No trial to date has compared the effect of anastrozole

treatment versus placebo on bone mineral density in the prevention

setting.

 

Materials and Methods: The bone sub-protocol of IBIS-II assessed changes

in the bone mineral density in postmenopausal women aged 40-70 years

with a high risk of breast cancer receiving anastrozole 1 mg/day versus

placebo for 5 years. Out of 1540 women recruited to date in the

prevention study, 613 women have taken part in the bone sub-protocol of

the study. Lumbar spine and femoral

neck bone mineral density have been assessed at baseline and 1 year by

DXA scans for 250 women at the time of analysis.

 

Results are expressed as mean

percentage change. Out of 250 women, 162 with normal bone mineral

density joined stratum-I of the study and received only monitoring

without bisphosphonate

treatment, 59 osteopenic women joined stratum-II and were further

randomised to

receive either risedronate or placebo, 29 osteoporotic women joined

stratum-III of

the study and all received treatment with risedronate.

 

Results: In stratum-I, a greater bone mineral density loss was observed

in

the anastrozole vs placebo group at both the lumbar spine (-2.5% vs.

-0.97%; P=

..002), and total hip (-1.34 vs. -0.37%; P= .02). In stratum-II, women

randomised to risedronate had higher bone mineral density scores both in

the anastrozole and in the placebo arm. The bone mineral density changes

were (risedronate vs. non-risedronate group; Spine 0.32% vs. -0.17%,

P=0.75, Hip 0.67% vs. -2.27%, P= .01) in the anastrozole arm, and (Spine

0.84% vs. -0.25%, P=.36; Hip -0.35% vs. -1.2%, P=.23) in the placebo

arm. In stratum-III, the BMD changes observed were (Spine 1.8% vs.

4.17%, P= .03; Hip -0.13% vs. 1.5%, P=.06) in the anastrozole and

placebo group, respectively.

 

Discussion: Women with normal bone mineral density at baseline had a

significant bone mineral density loss with anastrozole treatment.

However, women on anastrozole, who joined the trial with an osteopenic

or osteoporotic T-score,

gained bone mineral density after receiving risedronate treatment for a

year.

This data confirms the bone mineral density losses observed with third

generation AIs on breast cancer patients, but it is also reassuring that

bone

mineral density loss can be controlled if women receive DXA scans at

baseline and bisphosphonate treatment as needed along with AIs.

Longer-term follow-up and analysis on more bone mineral density data is

required to confirm the above

results. These data will be further updated at the time of meeting.