Abstract
Background: Quality of life (QoL) is severely affected by breast cancer (BC) and its treatment, particularly chemotherapy treatment. Psychological morbidity, illness perceptions, and self-efficacy for coping are important variables that impact QoL during the treatment of BC. The impact of cortisol on QoL has been poorly studied.
Objective: The aim of this study was to identify the contributing variables to QoL in women with BC receiving adjuvant chemotherapy, as well as the moderating role of cortisol in the relationship between treatment adverse effects and QoL.
Methods: This cross-sectional study included 112 women with BC undergoing chemotherapy who answered the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire, the Supplementary Questionnaire Breast Cancer Module, the Illness Perception Questionnaire, the Cancer Behavior Inventory-Brief Version, and the Hospital Anxiety and Depression Scale. In addition, salivary cortisol concentrations were also assessed.
Results: The strongest contributor to lower QoL was treatment adverse effects. The illness perception and the cancer stage also contributed to a lower QoL. Nadir cortisol moderated the relationship between adverse effects and QoL.
Conclusion: Breast cancer chemotherapy and illness perceptions, even at the beginning of treatment, showed a great impact on QoL.
Implications for Practice: It is important during chemotherapy to assess women's illness perceptions, as well as their stress levels to help women cope with the stress associated with treatment adverse effects. Monitoring cortisol is important as cortisol moderated the relationship between adverse effects and QoL. For those women struggling with stress, a reference to a mental health provider is warranted.