The impact of breast cancer diagnosis and treatment on body weight and weight-related lifestyle
Authors:   , de Kruif Johanna Theodora Catharina Maria 
Published: January 2023

Breast cancer is a major public health concern, in the Netherlands, 1 in 7 women are diagnosed with breast cancer in their lifetime. In women receiving chemotherapy, weight gain and undesirable changes in body composition is a common but poorly understood phenomenon, which is associated with disease recurrence, an increased risk of cardiovascular disease and diabetes, and a lower overall survival. Lifestyle such as dietary intake and exercise during chemotherapy may contribute to this phenomenon. This study is part of the COBRA study (Change Of Body composition in Breast cancer: All-in Assessment-study) a longitudinal observational mixed-methods study. The overall aim of this thesis was to investigate the perceptions of women with breast cancer, women without breast cancer, and Health Care Professioals (HCPs) on why potential changes in dietary intake, physical activity and body weight, and quality of life occur and how they deal with these potential changes.
Problems with healthy diet, physical activity, unexpected weight gain and its health risks were important concerns in women's need to contribute to their treatment and were sometimes exacerbated by a lack of information on how to deal with it. Despite HCPs indicated they considered it part of their role to provide information and support on weight gain during chemotherapy, little information was provided. HCPs experienced a lack of time and knowledge, and they preferred continued treatment to weight control. Weight gain was perceived as not an important health issue during treatment. All HCPs thought it is better that women themselves addressed their weight gain after chemotherapy.
In a separate study on non-Western women, we found that culture and religion affected these women’s experience of breast cancer. Women often associated breast cancer with taboo, death or bad luck. Religion offered these women guidance, strength and meaning to the disease, but also limited women to openly talk about their disease. Women experienced barriers to accessing health care, sometimes due to language difficulties. They perceived lifestyle factors had little influence on the treatment of cancer. However, after treatment they were more aware of a healthy lifestyle and weight management.
Women with breast cancer experienced physical consequences as changes in dietary intake, physical activity and body weight from both the disease and its treatment. We found in a mixed methods approach that physically active women managed to stay active and cope more easily with problems during chemotherapy than less active women with low energy intake. The latter unexpectedly gained weight, expressed a need for information on heathy diet and reported that fatigue made them even more inactive during chemotherapy. In addition to physical consequences, women experienced how psychological factors such as beliefs about their illness and coping strategies influenced the impact of diagnosis and treatment on their changes in lifestyle factors, body weight and perceived quality of life. By identifying specific characteristics, i.e., age and BMI; and prior expectations, attitude towards healthy lifestyle, confidence in own body, confidence in HCPs, and coping strategies related to level of mastery, four groups of women were distinguished: a monitoring group (active, adaptive coping), a struggling group (active, maladaptive coping), an overwhelmed group (passive, maladaptive coping) and a resigned group (passive, adaptive coping). In the current health care setting, where lifestyle modification programmes are not (yet) part of standard care, change is needed to promote and support a healthy lifestyle in women with breast cancer. With tailored specific education and behavioural support from HCPs, women in these four groups can be supported in their need to contribute to their treatment by optimally regulate their reactions to a health threat such as breast cancer and its treatment.