PLEASE NOTE: This is an updated evaluation of two stories that appeared in USA Today on Monday, April 17. One was on page 1A (“Bone drug cuts risk of breast cancer”), the other on page 7D (“Raloxifene or tamoxifen: which is the right drug for you?”).
The coverage presents the preliminary results from STAR, a large clinical trial comparing tamoxifen and raloxifene in postmenopausal women at increased risk of breast cancer. The study found comparable reduction in breast cancer risk. While the article reported that for the women taking raloxifene, the incidence of uterine cancer, blood clots, and cataracts were less than the women taking tamoxifen, only the difference in cataract was statistically significant. This oversight is major as the incidence of uterine cancer and blood clots may be among the factors a woman considers when deciding which, if either breast cancer risk treatment option, is right for her. The article did mention that the comparability in breast cancer reduction is only for invasive breast cancer; tamoxifen reduced the risk of less aggressive breast cancer (i.e. ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS) while raloxifene did not. If the risks for all breast cancer events had been compared, the reported outcome of the study may have differed. The story also included costs, although the National Cancer Institute as a source for those costs may have given wrong information.
Failure to present the absolute number of breast cancer cases and side effect cases in each study group serves to amplify concern about cancer risk. The side bar companion piece entitled “Raloxifene or tamoxifen: Which is the right drug for you?” presupposes that a drug is right for everyone.
The story provides comparative estimates from the National Cancer Institute of the price for tamoxifen and raloxifene. However, the estimated costs provided by the NCI do not appear to accurately reflect the market.
Failure to mention the lack of statistical significance for the incidence of uterine cancers and blood clots for women at increased risk of breast cancer taking raloxifene as compared with those taking tamoxifen is an important lack of framework.
Harms were presented only in relative terms. The reader should be given the absolute rates. (See “absolute vs. relative risk” on the home page under “Things You Should Know About Research Stories.”
The article discussed some recently released data from a large clinical trial comparing tamoxifen and raloxifene in postmenopausal women considered to be at increased risk of breast cancer. Though the study found that the reduction in invasive breast cancer was the same for the two drugs, the article failed to distinguish between differences in side effects that were and were not statistically significant (i.e. that there were 36% fewer uterine cancers and 29% fewer blood clots among women who took raloxifene were not statistically significant while the 21% fewer cataracts were statistically significant). As the purported benefit of raloxifene over tamoxifen is the difference in side effects, knowing which differences were stastically significant and which are not is important when determining the relative merit of one drug over the other. The article did point out that the incidence of two forms of non-invasive breast cancer (ductal carcinoma in situ and lobular carcinoma in situ) were higher for women taking raloxifene than for those taking tamoxifen; this difference was stastically significant.
While it was noted within the story that the average five-year breast cancer risk for the women in the study was 3.4%, the overall tone of the article was one of disease mongering. One quoted expert (chairman for one of the studies) is quoted as saying that as many as 10 million postmenopausal women are at increased risk for breast cancer. Failure to present the absolute number of breast cancer cases and side effect cases in each study group serves to amplify concern about cancer risk. The side bar companion piece entitled “Raloxifene or tamoxifen: Which is the right drug for you?” presupposes that a drug is right for everyone.
The results of this study, its analysis, and interpretation have not yet been peer reviewed or published. Two quotes, one from the executive director of Breast Cancer Action and a spokesperson from the American Cancer Society, contribute valuable cautionary interpretation for the rest of the material presented in the article.
The article mentioned tamoxifen, the only medication to date that has been approved by the FDA for reducing breast cancer risk in healthy women. However the article failed to mention that not doing anything, increased screening (such as more frequent mammograms, screening with MRI, ductal lavage) and prophylactic mastectomy are also options to decrease breast cancer risk.
Although the article mentions that doctors could prescribe raloxifene for the purpose of reducing breast cancer risk, it is not yet approved by the FDA for this purpose and would therefore represent an off-label use of this medication.
It’s clear from the story that the use of raloxifene as a medication to reduce breast cancer risk is new.
There is no evidence that this story relied solely or largely on a news release.