Adherence to Mediterranean Diet and Nutritional Status in Women with Breast Cancer: What Is Their Impact on Disease Progression and Recurrence-Free Patients' Survival?

Introduction: Nutritional status impacts the survival of patients with cancer. There are few studies that investigate the role of nutritional status on breast cancer survival in women with breast cancer, and even fewer regarding the impact of adhering to the Mediterranean diet (MD). The present study aims to assess the nutritional status, MD adherence, physical activity levels and health-related quality of life (HRQOL) in women diagnosed with breast cancer and evaluate these parameters regarding recurrence-free survival. Methods: A total of 114 women, aged 35-87 years old, diagnosed with breast cancer in Larissa, Greece, participated in the study. Tumor histopathology was reported, and anthropometric indices were measured by a trained nurse, while questionnaires regarding nutritional status (via mini nutritional assessment), HRQOL via EORTC QLQ-C30, physical activity levels via IPAQ and Mediterranean diet adherence via MedDietScore were administered. The participants were followed-up for a maximum time interval of 42 months or until recurrence occurred. Results: A total of 74% of patients were overweight or obese, while 4% of women were undernourished, and 28% were at risk of malnutrition. After 42 months of follow-up, 22 patients (19.3%) had relapsed. The median time to recurrence was 38 months (IQR: 33-40 months) and ranged between 23 to 42 months. Higher levels of MD adherence were significantly associated with lower body mass index (BMI) values, earlier disease stage, smaller tumor size, absence of lymph node metastases and better physical activity levels (p < 0.05). Normal nutritional status was significantly associated with higher BMI values and better health-related quality of life (p <= 0.05). In univariate analysis, patients with higher levels of MD adherence and well-nourished patients had significantly longer recurrence-free survival (p < 0.05). In multivariate analysis, MD adherence and nutritional status were independently associated with recurrence-free patients' survival after adjustment for several confounding factors (p < 0.05). Conclusions: The impact of MD on time to recurrence is still under investigation, and future interventional studies need to focus on the role of adhering to the MD before and after therapy in survival and breast cancer progression. Furthermore, the present study also highlights the importance of an adequate nutritional status on disease progression, and the need for nutritional assessment, education and intervention in women with breast cancer.