Low dose exemestane usage in breast cancer

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Published: 29 Jun 2017
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Dr Davide Serrano - European Institute of Oncology, Milan, Italy

Dr Serrano talks with ecancer at The Umberto Veronesi Milan Breast Cancer Conference about breast cancer prevention techniques and his aim to reduce the number of instances of the disease. He discusses the potential risk factors and looks at some preventative action that can be taken. 

Dr Serrano goes onto talk about the ongoing multi-centre trial looking at ER positive breast cancer and substituting low dose exemestane, a aromatase inhibitor, for tamoxifen. 

My work is mainly to develop new strategies to prevent cancer. Our goal is to reduce the incidence of the disease. There are several possibilities; of course, one is the lifestyle but, based on the risk level that a person can have, lifestyle may not be sufficient and we can use also some pharmacological intervention. For breast cancer historically we have tamoxifen that has been proved in several international clinical studies. High risk women can assume tamoxifen for five years and have a reduction in cancer incidence for quite a long time also after treatment cessation.
We started a new study with exemestane. Exemestane is an aromatase inhibitor and after the tamoxifen trial it has been done in several studies with this new compound. Also it has been proved that we can reduce the incidence of breast cancer with either anastrozole or exemestane. The problem is that in prevention you really need very safe drugs because people are healthy and they want to remain healthy. Exemestane, as all the aromatase inhibitors, can give, besides the [?? 1:47] symptoms also some problems with bone – reducing bone density and increasing bone fractures. So we tried to see if low dose exemestane can maintain the biological activity, reduce cell proliferation and eventually if we can prove that low dose exemestane can maintain this biological activity we can move forward and see if also side effects can be reduced by lowering the dose.
It’s a long way; medicine requires several steps before reaching a consensus and going to the public. So clinical trials are really important and it’s very important to have the capacity to involve women to collaborate with us to improve the knowledge, to develop these very important strategies to avoid cancer.
It’s a multicentric trial; it is being sponsored by NIH so the money comes from the US. We are the leading centre but there are three centres in the US and two in Italy. As I said, the European Institute of Oncology, Galliera Hospital in Genoa and MD Anderson, Columbia and the Moffatt Center in the US. The trial is a pre-surgical trial meaning that postmenopausal women with a diagnosis of breast cancer, ER positive, meaning that the breast cancer has to be hormone sensitive, will be randomised to three different doses of exemestane and after four weeks they undergo surgery. The main endpoint is the reduction of oestrogen levels because this is the activity of the drugs, so reduce the oestrogen level in the blood. The secondary endpoint is the reduction of proliferation.
Aromatase inhibitors can be used only in postmenopausal women so tamoxifen has a broader range of usage. Based on physical, for example if the person is overweight probably tamoxifen is better, works better; if the woman has had gynaecological problems probably aromatase inhibitors are better.