World-leading epidemiologist Prof Jack Cuzick talks to ecancer about his paper in the Lancet confirming that selective estrogen receptor modulators (SERMs) are both effective and safe for preventing breast cancer in women who are at high risk of the disease but who are not ill.
We’ve collected all of the studies together the first studies began in 1986 of studies that have looked at these drugs called serms selective estrogen receptor modulators in and their role in preventing breast cancer tamoxifen is one of them and it’s the only one that’s actually used to treat breast cancer and it gave us our first lead because when using it to prevent
Recurrence of breast cancer we discovered that it also prevented new tumors in the opposite breast and that led me some years ago to actually suggest that we should actually look at it in prevention so they’ve had there been now for major prevention trials doing that it’s absolutely proven now i mean the the reduction overall is about forty percent and it only well
Little while they get less breast cancer is reduced by forty percent i think there’s been a number of reluctant things the cardiologists have recognized for a long time that if you treat somebody before they get disease you could do a bigger you have to have been a bigger effect than waiting for them to get disease so if you went to your doctor with high cholesterol
And said and he said come back in a year we’ll see if you had a heart attack you wouldn’t be very pleased but in fact that’s what we do in breast cancer high-risk women simply get screened more often and they wait for the cancers to occur so this is the idea is to bring this paradigm of preventing breast cancer to the cancer field raloxifene actually started out
As a drug for osteoporosis and in a large trial in which women with osteoporosis were being treated to prevent bone fractures it was discovered that in fact they also had a reduction in breast cancer so that was identified and further studies were conducted with breast cancer as the primary endpoint and was discovered also had a major effect on preventing breast
Cancer there are two new ones well fairly new now one called laser fox afine and one called or zox afine again they both started out as osteoporosis drugs and the trials were in women with osteoporosis trying to prevent fractures and again they showed very big effects on breast cancer reduction we got all the trailers together to give us their individual patient
Data and we put all of this together into one big overview of all of these studies to get an overall estimate of the benefits and the risks of these different drugs and we found that there was a large reduction in breast cancer was thirty-eight percent overall it occurred not only during the five years of active treatment but continued for five years after that so
We’ve done a 10-year follow-up on all of these studies now these serms only work for what are called estrogen receptor-positive breast cancer this is about seventy to eighty percent of breast cancer depending on age and they reduce that by a little over fifty percent selecting high-risk is still something to do more work but the major factors are family history
A mother or sister with breast cancer below the age of 50 or two breast cancers in the family the other factors that are important and established are women with benign breast lumps that have abnormal features atypical hyperplasia lobular carcinoma in sight you and probably the most important factor but not currently used very much is breast density which can be
Seen on a mammogram worldwide now they’re estimated to be more than 1.4 million cases of breast cancer in the top ten percent of the population we probably have about twenty percent of those so that’s a little over a quarter of the million cases per year that we could find in this high-risk group that might be suitable for tamoxifen or assume two major side effects
Which are both fairly rare or thromboembolic disease blood clots and the risk is approximately doubled about eighty percent increase now that’s about the same as hormone replacement therapy so it is the the most serious side effect and we estimate that for example in a thousand women that took one of these drugs for five years you would have about six extra cases
The other other concern which is actually mixed it’s really only seen clearly it with tamoxifen is endometrial cancer and again that’s a little more than doubled with with tamoxifen but it’s quite rare and i think doctors have become much more aware that any abnormal bleeding in women with tamoxifen needs immediate investigation these cases are generally all being
Found very early where you can treat them with just a hysterectomy and nothing additional i think there’s clear evidence that this is a winner in terms of prevention it’s particularly to appropriate tamoxifen for premenopausal women because you don’t have the individual cancer risk we estimate that if you took high-risk women with roughly double the average risk
There would be about in every 1000 women over a ten-year period we would prevent about 20 breast cancers there would be about three extra endometrial cancers and about six extra thromboembolic events so the cancers are clearly the most series of those events and the effect sizes are larger so it’s clearly a winner yeah the newer serms sadly are not being promoted
For breast cancer prevention of them laser fox afine appear to have the best profile because not only did it prevent a little bit more breast cancer about fifty percent but it also had a beneficial effect on fractures which it was designed for but also heart disease and strokes so if you could get a preventative agent that would actually affect a range of diseases
Is particularly important in the general population or well women i think we need to raise the profile of the fact that cancer is a preventable disease just like the cardiologists have done people now consider high blood pressure high cholesterol to be a disease in fact all it is is a risk factor we have the similar risk factors for breast cancer and we should
Begin to treat them as well so the first thing is i think we need regulatory approval for these drugs sadly they’re all virtually out of patent now so the companies aren’t inclined to to go through the process of regulatory approval in the uk now the nice committee the national institute for clinical accidents is now recommended that either raloxifene or tamoxifen
Be considered for high-risk women so that’s a very positive step in the right direction and hopefully will provide the stimulus and the confidence for doctors to begin to use this more i think the next step though is to actually begin to educate gps and the population in general that breast cancer is a potentially preventable disease and we really should put more
Effort on doing that i believe they should they identify women who had a strong family history of breast cancer have had a benign lump or even those that have very dense breasts and discuss with them the options but i think the benefits do outweigh the risks for most of these women you
Transcribed from video
IMPAKT 2013: Long-term effectiveness of SERMs for preventing breast cancer By ecancer
