Dietary Constituents: Relationship with Breast Cancer Prognostic (MCC-SPAIN Follow-Up)

The aim of this study was to characterize the relationship between the intake of the major nutrients and prognosis in breast cancer. A cohort based on 1350 women with invasive (stage I-IV) breast cancer (BC) was followed up. Information about their dietary habits before diagnosis was collected using a semi-quantitative Food Frequency Questionnaire. Participants without FFQ or with implausible energy intake were excluded. The total amount consumed of each nutrient (Kcal/day) was divided into tertiles, considering as &ldquo:high intakes&rdquo: those above third tertile. The main effect studied was overall survival. Cox regression was used to assess the association between death and nutrient intake. During a median follow-up of 6.5 years, 171 deaths were observed. None of the nutrients analysed was associated with mortality in the whole sample. However, in normal-weight women (BMI 18.5&ndash:25 kg/m2) a high intake of carbohydrates (&ge:809 Kcal/day), specifically monosaccharides (&ge:468 Kcal/day), worsened prognostic compared to lowest (&le:352 Kcal/day). Hazard Ratios (HRs) for increasing tertiles of intake were HR:2.22 95%CI (1.04 to 4.72) and HR:2.59 95%CI (1.04 to 6.48), respectively (p trend = 0.04)). Conversely, high intakes of polyunsaturated fats (&ge:135Kcal/day) improved global survival (HR: 0.39 95%CI (0.15 to 1.02) p-trend = 0.05) compared to the lowest (&le:92.8 kcal/day). In addition, a protective effect was found substituting 100 kcal of carbohydrates with 100 kcal of fats in normal-weight women (HR: 0.76 95% CI (0.59 to 0.98)). Likewise, in premenopausal women a high intake of fats (&ge:811Kcal/day) showed a protective effect (HR:0.20 95%CI (0.04 to 0.98) p trend = 0.06). Finally, in Estrogen Receptors (ER) negative tumors, we found a protective effect of high intake of animal proteins (&ge:238 Kcal/day, HR: 0.24 95% CI (0.06 to 0.98). According to our results, menopausal status, BMI and ER status could play a role in the relationship between diet and BC survival and must be taken into account when studying the influence of different nutrients.