Effect of Mediterranean Diet on the prevalence of breast cancer relapse: preliminary results of the “SETA PROJECT”

Abstract

Background: Breast cancer is a multifactorial disease and diet is one of the factors affecting cancer initiation. Recent studies suggest that Mediterranean Diet can be used as a tool to prevent cancer occurrence. Aim of this case‐control study was to compare the recurrence of women treated for breast cancer and assigned to one of 2 groups: 1) free‐diet with dietary advice for cancer prevention; 2) Mediterranean Diet. Material and methods: 307 women with diagnosis of breast cancer and treated at the Department of Oncology‐hematology, Hospital of Piacenza (Italy) have been enrolled in the study. After surgical and/or medical treatment and/or radiotherapy, women have been asked if they wanted to follow a normal diet with dietary advice to reduce the occurrence of cancer relapse (Std‐Diet) or a Mediterranean Diet (Med‐Diet). The adherence to the Mediterranean diet was determined with the Med Score (range 0‐55) proposed by Trichopoulou. 199 women were included in the Std‐Diet group and 108 patients in the Med‐Diet group. Body mass index was recorded for each subjects. In addition a blood sample was taken, in the morning while fasting, for the determination of: glucose, cholesterol, insulin, vitamins A‐D‐E, sexual hormones, Ca, P, Mg, plant pigments (lycopene, beta‐carotene, lutein, zeaxanthin and cryptoxanthin), TNF‐alpha, IL‐1, IL‐6, Reactive Oxygen Metabolites (ROM). The women received a questionnaire about quality of life sf‐36 and physical activity. The comparison of cancer relapse between the 2 diets groups was carried out with the chi‐squaremethod, while the correlation of data was performed with the PROC CORR of SAS 9.2. All participants gave theirs written informed consensus and the research was approved by the Ethical Committee of the Hospital. Results: During the follow‐up, (3 years) 11 patients relapsed in the cohort with normal diet plus nutritional advice (Std‐Diet), while no recurrence was observed in the Med‐diet group. This difference is significant: chi26.19; P < 0.05. The Med‐Score resulted significantly correlated (r = 0.51; P < 0.01) with the beta‐carotene level in blood, while no significant relationship was observed with other pigments. According to this data the compliance of patients to Mediterranean diet could be estimated according to the level of pro‐vitamin A. Conclusions: The adoption of a Mediterranean Diet has reduced the risk of cancer recurrence. The levels of beta‐carotene can provide a good estimation of compliance to Mediterranean Diet.