The study that I will present at ASCO is testing the idea that women who present at diagnosis with breast cancer that has spread beyond the breast to other organs may benefit from treatment of the tumour in the breast. So classically the approach has been that once the tumour has spread to other parts of the body the breast tumour is not that important any longer and treatment of the breast tumour would not improve survival. So the treatment should focus on medical therapy for the cancer that is in other parts. But about fifteen or so years ago we looked at some information from a large database that suggested that perhaps it is important and it is useful to treat the primary tumour in the breast and that women will benefit from that treatment.

So there are always problems in interpreting data that is retrospective, that hasn’t been accumulated to test a specific idea. So there were many biases in that data and in subsequent other studies that were published that showed similar results suggesting benefit for treatment of the breast tumour. There were a number of clinical trials started that randomised women to testing this idea formally by randomising them to either a group that continued their medical treatment without specific therapy for the primary tumour site in the breast and those that were treated for the breast tumour as well as the systemic therapy. Our trial to be presented at ASCO is actually the third in this series. Two previous trials have been published and have shown conflicting results – one showing no benefit of treating the primary site in the breast and the other showing a benefit. So our trial matured recently and we are presenting the results of this analysis. We have a randomised trial where women were assigned to either continued medical treatment or surgery and radiation for the breast plus continued medical treatment.

What were the results?

We did not find any benefit related to the use of surgery and radiation for the primary tumour. So the survival in the two arms was exactly equal, in fact, and there was no suggestion that treatment of the primary tumour benefitted women. It didn’t seem to harm women overall either but clearly there was no benefit. And since all treatment carries some cost, surgery and radiation to the breast carries some cost, so if there is no benefit to it then clearly it is not something that should be pursued.

One of the secondary endpoints, an important secondary endpoint, was whether treatment of the tumour in the breast improves quality of life. Women who have a tumour in the breast and are being treated with medical therapy, chemotherapy or anti-hormone drugs or other drugs for their overall disease, disease in other sites as well, so those women can often see a shrinkage of the tumour in the breast related to that successful medical therapy. But sometimes the tumour in the breast will progress and so it can cause unpleasant symptoms. So it’s an unpleasant experience for a woman to have a tumour that’s growing in the breast. Part of the idea that we wanted to test was whether the removal and treatment of the tumour would improve a woman’s quality of life even if it didn’t improve her survival.

So the main endpoint was overall survival but a secondary endpoint was quality of life. So we compared quality of life in the two arms, those who got surgery and radiation for the breast and those who didn’t, and we actually did not find any difference in the quality of life either. So  the quality of life was impaired to an equal degree, it was not markedly impaired by the tumour in the breast but it was impaired to an equal degree in women who were treated for the tumour and those who weren’t treated for the tumour. The reason probably is that in women who get medical therapy, medical therapy really is improving to the point where it keeps the tumour controlled in the breast as well for a large number of women. So those who progress to the point where the tumour is actually bothering them in the breast are relatively few.

Overall that’s probably why we didn’t see a difference in the quality of life.

There are also people who feel that just the idea of having the tumour in the breast is a burden and so it’s something that the woman can see and feel sometimes. So just removing the tumour and relieving her of being aware of the tumour in the breast would be an advantage and that does not seem to be true. So women did not report any increase in their quality of life overall regardless of whether the tumour was removed or left alone.

Is there anything you would like to add?

I think that this has been a controversial area for many years now, certainly for the last 15-20 years it has been something that physicians have debated and that patients have found intuitively appealing. So when this idea was first presented and discussed many women felt that it made a lot of sense to have the tumour removed and treated in the breast. So for those women it will be useful to know that the burden of the local therapy, going through the surgery and going through the radiation, actually does not give them any objective advantage, both in terms of survival as well as with regards to quality of life.