A meta-analysis published in The Lancet looked at the role of SERMs (Selective Estrogen Receptor Modulators) and found that they do indeed play a role in reducing incidence of breast cancer recurrence for as many as ten years after initial diagnosis and treatment, with the greatest benefit in the first five years.
SERMs are drugs like tamoxifen that act on estrogen receptors. Estrogen receptors are proteins inside cells that are activated by estrogen and can then move to the cell nucleus and bind to the DNA. This can cause creation of tumors. I do not have the figures at hand, but I believe that around two-thirds of breast cancers are estrogen positive; that is, associated with over-expression of estrogen.
Different SERMs affect estrogen receptors in different ways, but essentially they either cause or block cell activity in different kinds of tissue (that’s the “selective” bit). The following table is from Wikipedia, where interested people can find relatively non-technical articles about some of these subjects. (Just please remember that I did say “relatively”.)
|clomifene||used in anovulation||antagonist at hypothalamus|
|femarelle||managing menopause symptoms, osteoporosis||agonist at brain and bone|
|ormeloxifene||contraception||agonist at bone; antagonist at breast and uterus|
|raloxifene||osteoporosis, breast cancer||agonist at bone; antagonist at breast and uterus|
|tamoxifen||breast cancer||agonist at bone and uterus, antagonist at breast|
|lasofoxifene||osteoporosis, breast cancer, vaginal atrophy||agonist at the bone, antagonist at breast and uterus|
The article, “Selective oestrogen receptor modulators in prevention of breast cancer: an updated meta-analysis of individual participant data” by Cuzick et al., is available at The Lancet as an early online publication dated today, 30 April 2013. (Free registration is required to view the article in full; a summary can be seen without registration.) It looked at four SERMs: tamoxifen, raloxifene, arzoxifene, and lasofoxifene in various studies.
A less technical description of the study is available online at MedPageToday in “SERMs Still Have Value for Breast Ca Prevention” by Charles Bankhead, who writes:
In spite of the demonstrated efficacy, SERMS continue to be ignored by patients and primary care physicians alike, “mainly because of concern about toxic effects and perceived unfavorable balance between benefits and harms,” the authors noted.
“Unfortunately, at the present time, none of these drugs are being actively marketed for breast cancer prevention,” they said. “Our longer-term assessment shows that the benefit-harm balance is now more favorable than that calculated for short-term follow-up, and, in view of this new evidence, assessment of these drugs, especially lasofoxifene, should be continued.”
As with any medical treatment–and perhaps even more so with cancer treatments–possible adverse effects must be weighed against potential benefits. I am a relatively savvy patient, but like everyone else I am dependent on my oncologist to interpret these and other findings in terms of my own history and current state of disease. Nevertheless, the results seem encouraging–if only as research that can help lead to treatment that will reduce the incidence of breast cancer recurrence.