Effect of raloxifene on the incidence of invasive breast cancer in postmenopausal women with osteoporosis categorized by breast cancer risk.

Abstract

PURPOSE:

To assess the effect of raloxifene, indicated for osteoporosis treatment and prevention, on invasive breast cancer in subgroups of postmenopausal women defined by risk factors for breast cancer.

EXPERIMENTAL DESIGN:

Data from the 4-year Multiple Outcomes of Raloxifene Evaluation (MORE) trial (N=7,705) and a follow-up study, the 4-year Continuing Outcomes Relevant to Evista (CORE) trial (N=4,011), were analyzed. Prespecified subgroups were defined by age (>or=65 versus<65 years), age at menopause (>or=49 versus<49 years), body mass index (>or=25 versus<25 kg/m2), family history of breast cancer (yes/no), serum estradiol level (5-10 versus<5, >10 versus<5 pmol/L), prior estrogen therapy (yes/no), and bone mass at MORE baseline, and 5-year predicted risk, assessed using the modified Gail model (>or=1.67 versus<1.67%), at CORE baseline. Time-to-first invasive breast cancer was analyzed using Cox proportional hazards models.

RESULTS:

In the placebo group, older age, higher estradiol level, and a family history of breast cancer were associated with an increased breast cancer risk (P<0.05). Raloxifene therapy was associated with a reduced breast cancer risk in both women at lower and those at higher breast cancer risk. Hazard ratio point estimates were 0.11 to 0.67, corresponding to a 33% to 89% reduction in breast cancer risk with raloxifene versus placebo. The therapy by family history interaction was significant (P=0.04).

CONCLUSIONS:

Raloxifene therapy was associated with a reduced risk of invasive breast cancer in postmenopausal women irrespective of the presence/absence of risk factors; its effect was greater in women with a family history of breast cancer.

• Authors: Marc E Lippman, Steven R Cummings, Damon P Disch, John L Mershon, Sherie A Dowsett, Jane A Cauley, Silvana Martino
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 12 Issue 17 Pg. 5242-7 (Sep 01 2006) ISSN: 1078-0432 [Print] United States
• PMID: 16951244 (Publication Type: Journal Article)

Chemical References

• Placebos
• Selective Estrogen Receptor Modulators
• Raloxifene Hydrochloride

Topics

• Aged
• Breast Neoplasms (drug therapy, epidemiology, prevention & control)
• Female
• Follow-Up Studies
• Humans
• Incidence
• Middle Aged
• Multivariate Analysis
• Neoplasm Invasiveness
• Osteoporosis, Postmenopausal (drug therapy, epidemiology)
• Placebos
• Raloxifene Hydrochloride (administration & dosage, therapeutic use)
• Randomized Controlled Trials as Topic (statistics & numerical data)
• Risk Factors
• Selective Estrogen Receptor Modulators (administration & dosage, therapeutic use)
• Treatment Outcome