Researchers release results of (STAR) breast cancer prevention trial

Below are comments from Len Lichtenfeld, MD, American Cancer Society deputy chief medical officer, in response to the results of the STAR trial.

"For years, doctors have offered tamoxifen to women at increased risk for breast cancer, after studies showed it could result in a nearly 50 percent reduction in invasive breast cancers in these women. At the same time, we also know tamoxifen has had side effects that have impacted the willingness of women and their physicians to use it. As a result many fewer women than anticipated have taken advantage of tamoxifen as a prevention option. We've been eagerly awaiting the results of the STAR trial, which was designed to compare the effectiveness of tamoxifen to another drug, raloxifene, which like tamoxifen blocks the effect of estrogen on breast tissue. The results released today show raloxifene is as effective as tamoxifen at reducing the risk of invasive breast cancer, with a better safety profile.

"But there's an important caveat. It is clear from this and previous studies that tamoxifen is also effective in reducing the risk of two important, non-invasive cancers: lobular carcinoma in situ (LCIS) and ductal carcinoma in situ (DCIS). The current trial shows raloxifene does not have this same benefit, meaning taking away the risk of increased uterine cancer and blood clots from tamoxifen comes at a price: the loss of the protective effect of tamoxifen to potentially prevent these non-invasive breast cancers. As a result, the outcome of the study is not as clear cut as we might have hoped for. It will take some time for experts to review the data to determine which of the two treatments is preferable.

"For now it will be very important for women an increased risk of breast cancer to make an informed decision with the advice of their physician as to which approach is best for them."