Breast Cancer Prevention Trial

This is all over the news, so you may have seen it already: raloxifene, an osteoporosis drug, may also help prevent breast cancer in high risk women and be an alternative to tamoxifen, as it appears to have fewer side effects.

Keep in mind that these are preliminary results of the STAR trial, taken from the NCI release:

"The numbers of invasive breast cancers in both groups of women were statistically equivalent."

"women in the raloxifene group had 29 percent fewer deep vein thromboses (blood clots in a major vein) and pulmonary embolisms (blood clots in the lung) than women in the tamoxifen group."

"The number of strokes occurring in both groups of women was statistically equivalent."

"While tamoxifen has been shown to reduce, by half, the incidence of lobular carcinoma in situ (LCIS) and ductal carcinoma in situ (DCIS), raloxifene did not have an effect on these diagnoses. (LCIS and DCIS are sometimes called noninvasive breast cancers.) Of the 9,726 women taking tamoxifen, 57 developed LCIS or DCIS, compared to 81 of 9,745 taking raloxifene."

Data was available for 19,471 women enrolled in the STAR trial, and "Women who participated in STAR were postmenopausal, at least 35 years old, and had an increased risk of breast cancer as determined by their age, family history of breast cancer, personal medical history, age at first menstrual period, and age at first live birth." The last of the bullet points above is notable, as it is seemingly the only point on which the drugs were not equivalent, or on which raloxifene did not perform better than tamoxifen. Some coverage of the trial also suggests that women who have already been using tamoxifen for several years may not see major benefits from switching.

Coverage:
National Cancer Institute
National Cancer Institute: STAR Questions & Answers
National Cancer Institute - overview of the STAR trial
New York Times
CNN
Washington Post
All Things Considered
NIH News - National Institutes of Health
Thoughts of An Average Woman - I disagree with her take on the study's validity, that there is no control in the study, because it seems that tamoxifen is the control. This is not an uncommon study design for comparing a new drug or a new use for a drug to one that is more established for a specific purpose. However, you might enjoy her blog anyway.

Technorati Tags: breast cancer; clinical trials; raloxifene; tamoxifen
MeSH Tags: Breast Neoplasms/prevention and control; Raloxifene; Tamoxifen