ASCO 2015

Raloxifene retained approximately 81% of the effectiveness of tamoxifen in preventing invasive breast cancer

Dr Lawrence Wickerham - NRG Oncology Research Group, Pittsburgh, USA

We entered about 20,000 women, otherwise healthy, at an increased risk for breast cancer. Half went on tamoxifen, half went on raloxifene and we’ve now followed them for more than ten years on average and have been able to show a number of interesting things. One, in the long term tamoxifen remains superior to raloxifene in the prevention of invasive breast cancer but raloxifene retains about 80% of tamoxifen’s benefits without a lot of the serious side effects.

Now, is that what you’ve now discovered with all the long follow-up?

We’ve been able to show that it’s a durable benefit. Initially at five years the results were very similar, the benefits from tamoxifen have emerged over time, benefits superior to raloxifene. We’ve also seen a greater increase in the side effects related to tamoxifen. Put together they both end up being options for women to consider.

Of course tamoxifen was a great idea, it hasn’t been taken up perhaps as well as might have been hoped, but raloxifene does have some subtle advantages, doesn’t it?

It does. It does not increase the risk of endometrial cancer at all and it has fewer blood clots, deep vein thrombosis, pulmonary emboli and it helps maintain bone.

And psychologically there are advantages.

It is, it’s not considered a cancer drug. It makes it more palatable to a lot of women to think that they’re taking something that’s helpful but not a cancer drug.

And you might want to take it to save your bones anyway.

That’s correct.

Yes. So would you wrap this up for me with the latest data right up to the present time? What are the recommendations for preventing breast cancer?

Women at increased risk for breast cancer, based on family history or other risk factors, if they’re premenopausal the only option is tamoxifen. Post-menopausal they now have two and perhaps more options: tamoxifen, raloxifene, and in the future perhaps aromatase inhibitors.

And what are your recommendations?

I’m a strong advocate in post-menopausal women of raloxifene as a first step – fewer side effects, better long-term prognosis.

So coming out of this ASCO meeting and your latest round-up, what do doctors remember from all of this as of the latest information?

I think if they identify women at increased risk they now have options to consider. In addition to screening and the extreme bilateral mastectomies they have the middle ground.