Physical activity status in relation to quality of life and dietary habits in breast cancer survivors: subset analyses of KROG 14-09 nationwide questionnaire study

Purpose: We investigated the relationship of physical activity with dietary habits and quality of life (QoL) in breast cancer survivors in accordance with the recommendations of the American Cancer Society. Methods: Data of 928 breast cancer survivors were obtained from the KROG 14-09 study to measure QoL in early phase after adjuvant radiotherapy. According to the extent of physical activity, survivors were divided into four groups: inactivity (0–149 min/week, N = 144), regular activity (150–450 min/week, N = 309), moderate activity (451–900 min/week, N = 229), and marked activity (901–1800 min/week, N = 164) excluding hyperactivity (> 1800 min/week, N = 82) as it is a difficult condition to recommend to survivors. Global physical activity questionnaire, 5-dimensional questionnaire by EuroQoL (EQ-5D-3L), QoL Questionnaire–breast cancer (QLQ-BR23) from EORTC, and dietary habits were surveyed. A linear-to-linear association test for EQ-5D-3L and Kruskal–Wallis analysis for QLQ-BR23 and dietary habit were conducted. Results: Overall, 15.5% respondents (144/928) were classified as physically inactive. The trends of frequent intake of fruits (p = 0.001) and vegetable (p = 0.005) and reluctance toward fatty food (p < 0.001) were observed in physically active groups. Mobility (p = 0.021) and anxiety (p = 0.030) of EQ-5D-3L, and systemic therapy side effect (p = 0.027) and future perspective (p = 0.008) of QLQ-BR23 were better in physically active groups besides body image (p = 0.003) for the survivors with breast-conserving surgery. However, moderate and marked activities did not further improve QoL than regular activity. Conclusion: Physicians and care-givers have to pay attention to inactive survivors to boost their physical activity, thereby facilitating a better QoL and dietary habit.