EVALUATION OF AN EDUCATIONAL PROGRAM OF DIET AND PHYSICAL ACTIVITY ON HEALTH AND QUALITY OF LIFE IN WOMEN DIAGNOSED WITH BREAST CANCER.

Background: Healthy diets and exercise are two modifiable lifestyle factors associated with more favourable breast cancer (BC) outcomes and cardiometabolic health. We tested a low glycemic index (GI) Mediterranean diet (MedDiet) and exercise, within vitamin D sufficiency, on BC recurrence, cardiometabolic risk factors and quality of life. Methods: Women were contacted within 12 months of primary BC diagnosis (stages I-III) in 7 oncologic centres in Italy. Consenting participants were randomized to one of two lifestyle treatments lasting 33 months: 1) positive control (n=249), lower intensity advice on Mediterranean diet and avoidance of sedentary behavior; 2) test (n=243), higher intensity advice on low-GI MedDiet and 30-minute daily brisk walking. Oral vitamin D3 was administered to avoid insufficiency. Data were collected quarterly on health status, anthropometry, 7-day food records, daily steps and serum 25-OH-D. Intention-to-treat analysis was conducted for the main outcome (recurrence) comparing test to control. Hazard ratios (HR) and 95% confidence intervals (CI) were computed by Cox models. An observational analysis of the entire cohort was also performed testing the association between adherence to the higher intensity program and risk of disease recurrence. Differences in dietary and body weight parameters were tested at 1-year with Student’s t-test and ANCOVA where fit. Results: In the test arm, after 1-year intervention, dietary GI decreased from 56.4±4.1 to 48.3±5.5 (low-GI<55), adherence to the MedDiet increased by 23%, dietary fiber by 40% to 19g/1000 kcal, physical activity increased from 5624±2730 to 7119±3349 daily steps and serum 25(OH)D increased from 26.9±13.5 to 50.8±12.7 ng/mL. These changes were significantly larger from controls (p<0.03). Weight loss at 1-year was significantly greater in the test arm by -3 kg or -4.2% (BMI from 27.5±5.7 to 26.3±5.4 kg/m2) compared to -1.7 kg or -2.4% (BMI from 27.2±5.1 to 26.6±5.1 kg/m2) in the control arm (p<0.0043). Weight loss was particularly greater in those who consumed higher nuts. Each 10g/d increment of total nuts was associated with an additional body weight loss of 0.36 kg (p<0.028). The anti-atherogenic serum HDL-cholesterol increased from 57.3±14.7 to 63.9±14.9 mg/dL in the test arm and from 58.0±15.2 to 62.4±15.2 mg/dL in controls. Waist circumference, triglycerides and blood pressure significantly decreased in both arms without differences among treatments. Presence of metabolic syndrome dropped by 66% in the test arm and 35% in controls (p=0.008). Improved health-related quality of life (global status) was observed at 1-year follow-up (p<0.001), particularly for parameters regarding physical, role and social functioning, fatigue, dyspnea and constipation. During the 33-month follow-up a total of 37 recurrences were observed by ITT analysis with no differences between arms (HR=0.94; 95%CI: 0.49-1.79). In the observational analysis, those who were more adherent to the higher intensity program showed a tendency of lower BC recurrence (HR=0.61; 95%CI: 0.27-1.40) which reached significance in hormone-positive BC (HR=0.24; 95%CI: 0.06-0.95). Conclusions: Lifestyle counselling improved diet quality, physical activity and circulating vitamin D and resulted in weight loss, lower prevalence of the metabolic syndrome and improved quality of life. Higher adherence to a low-GI MedDiet together with moderate physical activity on a background of vitamin D sufficiency was associated with lower risk of BC recurrence which reached significance in hormone-positive BC (82% of the total sample). Considering that BC survivors face a high risk of chronic disease and mortality during the long-term adjuvant therapy, it appears reasonable to recommend a safe and low-cost lifestyle program inclusive of Mediterranean diet with low GI carbohydrates, physical activity and avoidance of hypovitaminosis D, to women newly diagnosed with BC.