HRT and breast cancer – more red flags

Posted by Liz on Oct 22, 2010 in breast cancer, HRT | 2 comments

More bad news from the Women’s Health Initiative study and hormone replacement therapy (HRT, combined estrogen and progestin) front: not only does combined HRT appear to double the risk for breast cancer in some women, but these cancers are more invasive/agressive and more likely to lead to death.

The WHI findings have been repeatedly criticized by HRT advocates, who claim that the the women who were studied were not representative of the typical menopausal population, e.g. they were older and well past menopause at enrollment. So it is true that the potential benefits of HRT that might have been experienced by younger women were not explored. Indeed, time on hormones and the relationship between hormone use and how far into menopause a woman is can influence risk, as can the progestagen component. (If you want to read more about these specific factors, click on the links.) Nevertheless, what is also clear is that following the 2002 findings and the significant decline in HRT prescriptions, a substantial decrease in breast cancer rates were observed in both the US and Canada, so much so that the Canadian Cancer Society recently recommended that HRT be taken only as a last resort.

And the latest study findings?

In their continuing quest to determine insights into the risk-benefit ratio of HRT, researchers continued to follow and evaluate data from 83% (12,788) original trial participants. They found that HRT increased the incidence of invasive breast cancers by as much as 8% (compared with placebo), and that these cancers were also likelier to spread to the lymph nodes (24% of women taking HRT were found to have lymph node tumors compared to 16% of women taking placebo). Moreover, twice as many women on HRT died as the result of their cancer.

In an accompanying editorial, Dr. Peter Bach, a health outcomes researcher from Sloan-Kettering Medical Center in New York City, suggests that the latest study findings may only be the tip of the iceberg and that “it is possible that the increase in breast cancer deaths due to hormone therapy has been underestimated in the current study and that with longer follow-up, the deleterious effect will appear larger.” Additionally, he notes that “available data dictate caution in the current approach to hormone therapy, particularly because one of the lessons from the WHI is that physicians are ill-equipped to anticipate the effects of hormone therapy on long-term health.” Nor, have short-term approaches to hormone therapy been proven in clinical trials. As Dr. Bach points out, how can practitioners help patients make informed decisions if they are ill-informed themselves and the information, “speculative.” Nevertheless, the North American Menopause Society is taking the opposite stance, stating that ” clinicians can help women put the breast cancer risk into perspective by informing them that the increased risk of breast cancer using estrogen plus progestogen for 5 years is very similar to the increased risk of breast cancer associated with having menopause 5 years later. This increased risk of breast cancer occurs with a woman’s own internal, natural estrogen and progesterone.”

If this study and its accompanying editorial don’t raise a few flags, nothing will. And despite the pro-HRT stance of the North American Menopause Society, I encourage all women to start educating themselves before making the HRT leap. What’s more, be aware that once you start taking hormones, your practitioner might not be able to provide evidenced-based information on how to stop them, should you decide that they are not for you.

Ask yourselves, what is the trade-off here?

(Reuters Health, as usual, has a few more gems from this study that are required reading. You can find them here.)