Depressed Mood in Breast Cancer Survivors: Associations with Physical Activity, Cancer-related Fatigue, Quality of Life, and Fitness Level

Purpose: One out of five cancer survivors suffer from depression after oncology treatment. The aim of this study was to examine the relationship between depression and quality of life (QoL), cancer-related symptoms, physical activity level, health-related fitness, and salivary flow rate in breast cancer survivors.

Method: 108 breast cancer survivors in the year after the conclusion of treatment were included in this cross-sectional study. Demographic and clinically relevant information, cancer-related fatigue (Piper Fatigue Scale), QoL (QLQ-Br23 module), pain intensity VAS scale, salivary flow rate, physical activity level (Minnesota Leisure Time Physical Activity Questionnaire), and health-related fitness were assessed in all participants. Depressed mood was measured with the Profile of Mood States (POMS) Depression subscale.

Results: Significant positive correlations between depressed mood and fatigue, systemic side effects, perceived shoulder pain, and breast-arms symptoms (r ranged between .57 and .28, P < .01) were found. In addition, significant negative correlations between depressed mood and body image, future perspective, force handgrip, and physical activity level (r ranged between -.41 and -.19; p < .05) were found. Regression analyses revealed that cancer-related fatigue, physical activity level, systemic side effects, and body image were significant predictors of depressed mood, and when combined, they explained 39.6% of the variance in depressed mood.

Conclusions: Cancer-related fatigue, physical activity level, and QoL partially explain the variability of depressed mood in breast cancer survivors. This paper facilitates a better understanding of the relationship between depressed mood and possible factors associated with it.