Diet has been found to influence hormone production and metabolism which in turn could affect the incidence of hormone related cancers. Consumption of soy-containing foods, known to be rich in phytoestrogens, is thought to be one of the chemoprotective factors against breast cancer in Asian populations. Phytoestrogens have a wide range of metabolic effects and may have a role in effecting breast cancer risk. Although there is mounting evidence of the positive influence of phytoestrogens on breast cancer risk, very little research has been carried out in humans as to the effects of phytoestrogens on breast cancer recurrence and survival. The DietCompLyf study aims to explore this effect by carrying out an observational study in 3,000 breast cancer women in the UK. The effects of diet, lifestyle practices and use of complementary treatments will also be investigated. Participants are recruited 9-15 months post-diagnosis and followed up for 5 years. Questionnaires as well as blood and urine samples are collected annually.

Women matching the eligibility criteria are consented at breast cancer follow-up hospital visits. Blood and urine samples are then collected and questionnaires are provided for the participants to take away and return within 4 weeks. The process of sample collection and questionnaire provision is repeated for visit at years 3 and 5.

Year 2 and 4 study visit vary in that questionnaires including a 7 day food diary are sent to participants at home to be filled in 7 days before their scheduled follow-up appointment. At hospital, blood and urine samples are collected as usual.

Inclusion Criteria:

• Women with histologically confirmed invasive primary breast cancer grades I to III.
• age up to and including 75 years old

Exclusion Criteria:

• Previous cancer with the exception of basal cell carcinoma
• Concomitant primary cancer
• Bilateral cancer of the breast
• Psychological problems
• Cognitive impairment
• Poor understanding of English

Breast cancer clinics in UK