This story summarized some of the findings from a recent New England Journal of Medicine article on the BIG I-98 Trial, which randomized approximately 8,000 women to either letrozole or tamoxifen for 5 years. The outcome of this study and similar large-scale, randomized double-blind trials have shown that aromatase inhibitors are effective in reducing rates of breast cancer recurrence in post-menopausal women with estrogen receptor positive tumors. However, there is not enough emphasis here that this is only for post menopausal women with invasive disease — e.g. last quote citing 800,000 women assumes all ER/PR positive women are eligible.The FDA has approved two aromatase inhibitors, Letrozole and Arimidex, for early-stage breast cancer. While this story provides a decent overview of how these medications work and the findings on which the new FDA approval is based, there is little information on some of the potentially serious side effects noted in the women who look letrozole. These side effects include an increase in cholesterol levels and cardiovascular disease, as well as a significant increase in the risk of bone fractures. There are no quantitative 5-year estimates of these side effects, nor is there a quantitative comparison with the Tamoxifen group, though the safety of each drug is briefly mentioned. Additionally, there is no mention of the cost of either drug. Since hormonal drug regimens (i.e. tamoxifen alone, aromatase inhibitors alone or aromatase inhibitors following a course of tamoxifen) might be prescribed for 5 years or more, a cost comparison would be important. Itâ€™s good that the story points out that the study is funded by pharmaceutical money and that some of the researchers own stock in Novartis. An independent source from the National Cancer Institute is quoted for balance, presumably with no ties to pharmaceutical funding.
Cost of treatment not mentioned.
5-year estimated outcomes were given after only 2 years of data. No quantitative data on safety presented. Absolute numbers
provided. Limited long term data and small absolute benefit are key issues here.
Does not mention the increase in
cholesterol and cardiovascular disease among the women in the aromatase inhibitor group. Tamoxifen may have a positive,
cholesterol-lowering effect, which is also not mentioned.
Study design not adequately discussed. It didn’t really describe
that some of the data were likely gathered on women with more advanced disease where the benefits would be bigger.
Gives estimates of women diagnosed with this type of breast cancer. Perhaps not enough
emphasis that this is only for post menopausal women with invasive disease — e.g. last line in story assumes all estrogen
receptor/progesterone receptor positive women are eligible.
Journalist notes that the study was
funded by Novartis, maker of Femara, and that many of the researchers own stock in this company or in companies for rival
adjuvant drug treatment, tamoxifen, as well as some side effects of both of the aromatase inhibitor drugs (Femara and
Arimide) studied as well as Tamoxifen.
Story about FDA approval for women with early-stage invasive disease.
Discusses how drug is already
in use for women with advanced breast cancer.