BACR & ECMC: Therapeutic interventions for cancer prevention

Food, diet and prostate cancer

Prof Richard Mithen – Institute of Food Research, Norwich, UK

I’m talking about our work which has been looking at how we can prevent the progression of prostate cancer through dietary intervention and specifically with a food product derived from a broccoli based product. We’ve been working on this actually for about thirty years, I suppose; there’s lots of observational epidemiological evidence that people who eat high amounts of brassica vegetables, things like broccoli, cabbage, kale in their diet, have a lower incidence of cancer but there’s very little experimental evidence, at least in humans, there’s lots of evidence for mice and rat studies. So we’re doing a study based in Norfolk in which we have men who have a current diagnosis of prostate cancer, localised prostate cancer, and these men choose not to have surgery, they remain on a programme called active surveillance and they are very happy to take part in a dietary intervention. The experiment is mainly that they have one portion of a broccoli based soup per week for twelve months and we have three different types of broccoli which have different levels of specific compounds in and at the end of twelve months we hope to find out if one of these types of broccoli are better than another. We do this by taking biopsies, and this is normal clinical care that men are under, we take biopsies before the intervention and measure how much cancer they have in their prostate gland and at the end of twelve months we do it again and we can see whether the cancer has progressed or got less or stayed the same.

We’re also measuring different changes in the metabolism and the gene expression in the prostate tissue. From that experiment we hope, if our results are positive and we’ll know what the results will be in about… towards the end of 2017, to then to do a much larger study which will involve maybe a thousand or two thousand men. But that’s to come, we have to get the results of our current study first.

Are there any indications of what the results might be?

Not really. The study is blinded in that we have men on three different diets, three different types of broccoli and I don’t know what type of diet they’re on and they don’t know what type of diet. However, we did get ethical permission to see if there are some changes from a very early group, so the first fifteen volunteers and we’re able to analyse their tissue just so we know things are happening. So we have been able to detect changes which are due to the dietary intervention. And certainly some men we see more changes than others but at the moment I can’t say which are the diets that might be related to.

What led you to conduct this study?

My background is actually as a plant scientist and I started my career working on plant genetics. I worked quite a lot on brassica crops which is why I got involved in broccoli and then part of that was actually looking at their chemistry – why they accumulated these particular compounds, particularly in terms of how they defended themselves against pests and diseases. I spent some time collecting wild brassicas from particularly around the Mediterranean and we collected some particularly interesting ones from Sicily. I began using those in a breeding programme with broccoli and I think the collecting was in 1983 and my main breeding work was in the early ‘90s. Then it was in the early ‘90s that the first information became available that there seemed to be an association between reduction risk of cancer and people who had high amount of these particular vegetables. So my interest began to look at the link between plant chemistry and human health. I suppose over the next twenty years my research group has moved from doing plant genetics, which we don’t do any of anymore, into doing human genetics and human nutrition and cancer biology. So it’s been a bit of a journey. However, whether you’re dealing with human cancer biology or plants, at the basis of it is all genomics. And so whether we’re dealing with plant DNA or human DNA it’s actually much the same.

Have there been any other specific areas that have been of interest to you here at the BACR?

Plenty, I mean the conference has been excellent. It is still amazing to me that with our aging population, the challenges within the NHS and also our advances in the diagnosis and detection of cancer, we don’t have more investment in cancer prevention and stopping early cancers from progressing. So this is a really interesting conference, it’s bringing together people from all sorts of different disciplines. The work on aspirin, metformin, very interesting. So it’s a great conference, the organisers have done a great job but again I would like to see government and other charities putting more money into stopping cancer progressing at the early stages rather than just trying to deal with late stage disease.