By Lynley Hargreaves 29/10/2015

Dr Anita Dunbier
Dr Anita Dunbier

Breast cancer survival rates have improved by a third since the 1970s and taking the humble aspirin may help boost survival rates further still. University of Otago Senior Lecturer Dr Anita Dunbier explains why such a low-cost drug has been overlooked, why it works, and how her team is testing aspirin’s benefits in a new South Island-based medical trial.

Should we all just start taking aspirin every day?

Probably not yet as there are risks in taking aspirin too. The evidence we have at the moment suggests it is likely to be helpful and some people are already using aspirin based on these findings. Speaking specifically about breast cancer, any such decision would need to be made alongside your doctor and it would depend on the type of breast cancer. Generally, we’re still a little way from being able to determine exactly which patients should definitely take aspirin.

How long has this been known?

There has been some suggestion that aspirin can reduce the risk of developing cancer and improve outcomes for those who already have cancers for about a decade now. However, there has never really been an incentive for drug companies to fund the randomized trials that could prove it as aspirin has no patent-protection. However, a large breast cancer study involving patients who were taking aspirin for other reasons came out in 2010 and a few smaller studies since then have highlighted its potential importance for breast cancer. At the moment there is a large study about to start in the UK where they’re going to give aspirin for five years to patients with a range of different cancers.

Are you trialling giving patients aspirin long term?

No, we’re looking at how aspirin works together with existing anti-cancer drugs over quite a short time frame. The hypothesis we’re testing in particular is whether it is useful in combination with the anti-hormone therapy common in breast cancer treatment. We don’t have results yet as we’re just recruiting patients now, but we’re doing what we call a window study where we give the patients treatment for a short period of time. Then we look for a molecular marker called Ki67 – this is kind of like a molecular speedometer, which tells us how fast the cells are growing. Roughly two weeks before they have surgery we give either anti-hormone treatment only or anti-hormone plus aspirin. We can then take  a sample at the time of treatment and another at surgery, and compare what’s happened.

What difference is aspirin likely to make?

Aspirin blocks inflammation generally, and inflammation is important for many diseases. With cancer, there’s an increase in inflammatory signaling and immune cells entering the tumour. In some situations these changes help the cancer cells because the immune cells that come in produce a lot of growth factors. Basically, signals are sent out for the immune system to come rescue the tumour cells and it seems the aspirin and other drugs may be able to block these signals.

A Marsden Fast-Start grant allowed us to further investigate and find two targets – two gene expression changes – that we’re now focused on blocking.

What difference is this likely to make to cancer treatments?

Aspirin is a very cheap drug, whereas some of the treatments it could be used alongside can cost up to $200,000 for a six month course. So, if aspirin can improve the response to these very expensive drugs, that is a huge medical gain.

These interviews are supported by the Royal Society of New Zealand, which promotes, invests in and celebrates excellence in people and ideas, for the benefit of all New Zealanders.