The DietCompLyf study: Breast cancer survival and phytoestrogen consumption

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Published: 12 Nov 2013
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Dr Ruth Swann - University of Westminster, UK

Dr Ruth Swann talks to ecancer at the 2013 NCRI Cancer Conference about breast cancer survival rates and the largest prospective observational study that examined the relationship between diet and lifestyle and breast cancer recurrence and survival rates of patients in the UK.

The DietCompLyf study showed a significant inverse association between pre-diagnosis phytoestrogen consumption and possession of breast cancer risk factors. The data from the study will provide the necessary evidence base on which to test dietary and lifestyle recommendations for breast cancer patients, the overall aim of which is to reduce breast cancer recurrence rates.

It’s a prospective longitudinal cohort study looking at women with breast cancer in the UK, so just over 3,000 women have been recruited from various hospitals all around to give a representation of the breast cancer patient population. The women are recruited about a year after cancer diagnosis so they’ve finished their chemotherapy and radiotherapy and they’re recruited onto the study and followed up for annual follow-up visits up to five years post-diagnosis. During that time the patients complete self-reported questionnaires on diet, lifestyle, quality of life and general health and give biological samples throughout each study visit. So from this we can build up a big picture from each individual about their diet and lifestyle and how this could impact, if at all, on recurrence and survival rates from each individual.

So we’re looking at diet as a whole and different food groups but specifically we’re looking at plant oestrogens because oestrogen is a hormone which is associated with breast cancer so we’re interested to see if there is a relationship between plant oestrogens that are consumed and breast cancer survival.

What foods would you find these phytoestrogens in?

There are two main classes of phytoestrogens that are consumed and these differ in world populations as well. So in East Asia there’s a class of phytoestrogens called isoflavones which are present in high quantities in soya products and legumes and mostly consumed by Eastern populations whereas in the UK the commonly consumed are another type of phytoestrogen which are consumed in nuts, seeds, fruits and vegetables, so mostly associated with a healthy diet, really.

What did you find?

So far recruitment finished a few years ago so we’ve been collecting all the data from the questionnaires. We’ve just done descriptive results on the patients to see what type of person we have on the study and we have noticed differences between people that eat these phytoestrogens and their lifestyle behaviours, so depending on what age they are and other lifestyle factors such as their weight and if they take supplements and factors like that. We’re hoping to complete survival analysis next year once all the patients are complete on the study.

We initially wanted to look to see if there was a relationship between the phytoestrogen intake before diagnosis and tumour characteristics at diagnosis that are associated with prognostic factors. There wasn’t any significant association with the phytoestrogen consumption and tumour factors but there was an association with phytoestrogen intake and risk factors for breast cancer such as the BMI and other lifestyle factors.

We’re just looking at the profile of the individuals at the moment. When we come on to doing the survival analysis we’ll take into account all the lifestyle factors that could be associated with this as well to try and tease out if there is a relationship there.