Depressed mood in breast cancer survivors: Associations with physical activity, cancer-related fatigue, quality of life, and fitness level

Abstract

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.

Introduction

One out of five breast cancer survivors suffer from depression after oncology treatment, similar to other common cancer types (Khan and Amatya, 2013). This cancer-related symptom is twice as high in breast cancer survivors compared with the general female population 12 months after diagnosis (Burgess et al., 2005). Frequently, depression appears to be associated with other cancer-related symptoms such as pain (Kyranou et al., 2013), and fatigue (Laird et al., 2011; Thornton et al., 2010). The contributions of different physical, psychological, and related oncology process factors to fatigue have been explored previously (Cantarero-Villanueva et al., 2011). To the best of our knowledge, no similar approach has been used to study depressed mood.

The mechanisms involved in the genesis of depression in breast cancer survivors are not well understood. Factors related to the patient, such as loneliness, rather than to the disease or treatment increase the risk of depression (Jaremka et al., 2013). Nevertheless, recurrence of disease is clearly associated with depression in this population (Burgess et al., 2005). Loss of hope and uncertainty about the future could be an important factor associated with psychological problems such as depression (Burgess et al., 2005).

Neuroendocrine-immune models have been used to explain the genesis of depression in breast cancer survivors (Thornton et al., 2010). Saliva plays a relevant role in the immune response (Diaz-Arnold and Marek, 2002). Salivary flow rate is a recognized marker of autonomic nervous system function that could be affected by perceived stress, depression, or oncology treatment (Arhakis et al., 2013).

The relationship between depression and physical activity could be bidirectional. On the one hand, cancer patients decrease their level of physical activity following a cancer diagnosis (Kwan et al., 2012). Besides, oncology treatment as surgery could have a large impact on the patient's mood (Frazzetto et al., 2012). For other side, physical activity has a protective effect against depression (Bäckmand et al., 2003). Consequently, the contributions of physical activity and health-related fitness to depression need to be understood.

The presence of depression has been associated negatively with quality of life (QoL) in breast cancer survivors (Frazzetto et al., 2012), as has the presence of concomitant cancer-related symptoms such as fatigue or pain (Laird et al., 2011; Thornton et al., 2010). Changes in different aspects of QoL, such as sexual functioning, side effects, or loss of future perspective, could influence the loss of the meaning of health and life after a cancer diagnosis (Frazzetto et al., 2012). Understanding the contribution of these correlates of QoL and the presence of different cancer-related symptoms in explaining depression is a recognized gap in research on cancer-related symptoms during the survivorship phase (Lueboonthavatchai, 2007)

A clear understanding of the variables that explain depressed mood in breast cancer survivors could make possible to implement adequate strategies to reduce this disturbing psychological problem, which has an increased risk of noncompliance with hormone therapy during the survivorship phase (Hadji et al., 2013) and a reduced QoL (Sheppard et al., 2013).

The aim of this study was to examine the relationship between depressed mood and QoL, cancer-related symptoms, physical activity level, health-related fitness, and salivary flow rate in breast cancer survivors.