Fatigue mediates the relationship between physical fitness and quality of life in cancer survivors

doi:10.1016/j.jsams.2012.05.014

Journal of Science and Medicine in Sport

Volume 16, Issue 2, March 2013, Pages 99-104

https://doi.org/10.1016/j.jsams.2012.05.014 Get rights and content

Abstract

Objectives

This study aims to investigate whether fatigue mediates the association between physical fitness and quality of life.

Design

Uncontrolled pre–post intervention design.

Methods

Pre- and post-intervention measurements were conducted in 119 patients who completed chemotherapy treatment for various types of cancer. The intervention was an 18-week exercise programme consisting of high-intensity resistance and interval training. We assessed physical fitness – peak oxygen uptake and peak power output – self-reported fatigue (Multidimensional Fatigue Inventory – subscales general fatigue, physical fatigue, reduced activity, reduced motivation, and mental fatigue-, and fatigue symptom scale of EORTC QLQ-C30) and quality of life (EORTC QLQ-C30, subscale global quality of life). Linear regression analyses were conducted on the residual change scores of the variables. The mediated effect of fatigue on the association between physical fitness and quality of life was examined using the products of coefficient method. Bootstrapping was used to calculate the confidence intervals.

Results

We found significant associations between changes in physical fitness and global quality of life, between physical fitness and fatigue, and between fatigue and global quality of life. General fatigue mediated the positive association between peak power output and global quality of life, accounting for 82% of the total association. Physical fatigue, reduced activity, reduced motivation, and fatigue symptom were also mediators of this association. The mediation effects accounted for 91%, 76%, 38% and 71% of the total association, respectively. Reduced activity and reduced motivation mediated the association between peak oxygen uptake and global quality of life. Multiple mediation analyses showed that physical aspects of fatigue were stronger mediators than mental aspects.

Conclusions

General fatigue and physical aspects of fatigue mediate the relationship between physical fitness and quality of life in cancer survivors. We found no mediating effect of mental fatigue.

Introduction

Survival after cancer has improved substantially due to advances in early detection and treatment of cancer. In the Netherlands, 5-year cancer survival rates have improved up to 52% for male and 61% for female patients across all cancers.¹ However, cancer and its treatment are often associated with prolonged adverse psychosocial and physical symptoms including increased risk of anxiety, depression, fatigue, and reduced physical fitness and quality of life (QoL).2, 3, 4

Several literature reviews have reported that physical exercise may improve the QoL of cancer patients.2, 5 In a previous study, we evaluated the effects of an 18-week high intensity resistance exercise programme on physical fitness, fatigue and QoL in 57 cancer patients who completed chemotherapy.⁶ We found significant improvements in patients’ global QoL after completion of the intervention (effect size = 0.82; 95% confidence interval (CI) = 0.53; 1.11),⁶ and these improvements persisted to 1 year follow up.⁷ However, the mechanism (i.e. mediators) underlying improvements in QoL are unclear. A possible mediator of exercise-induced improvements in QoL is fatigue (Supplement 1).

Fatigue has been identified as one of the most common and distressing symptoms of cancer patients,8, 9 having a profound effect on QoL.9, 10 Previous meta-analyses have shown that physical exercise may reduce fatigue.5, 11, 12 Schwartz¹³ evaluated the effects of an 8-week home-based, low-to-moderate intensity aerobic exercise programme on fatigue and QoL in a small sample of 27 women who received chemotherapy for breast cancer. She reported that functional ability and energy expenditure were associated with QoL, and that these associations were mediated by fatigue.¹³ However, it is unclear whether these findings are valid for other parameters of physical fitness, for patients who are in a different phase of cancer treatment, or for other types of exercise programmes. More insight into the mechanisms of how exercise improves QoL is necessary for the systematic progression of research in this field and to better inform future exercise-based cancer rehabilitation. Therefore, the current study aims to investigate whether changes in fatigue mediate the association between changes in physical fitness and changes in QoL in a relatively large sample of patients who completed a high-intensity exercise programme after completion of chemotherapy for various types of cancer.

Section snippets

Methods

We conducted an uncontrolled clinical trial with a pre–post-test design in the Maxima Medical Centre, Veldhoven, the Netherlands. From March 2002 to January 2007, patients enrolled in an 18-week high-intensity exercise programme that was implemented as part of usual care for cancer survivors. Patients with histological confirmed cancer with no indication of recurrent or progressive disease and who had completed chemotherapy with curative intention were eligible. Exclusion criteria were: (1) not

Results

Table 2 presents pre- and post-intervention results on physical fitness, fatigue and HRQoL. At post-intervention, significant improvements were found for physical fitness, fatigue and HRQoL compared with pre-intervention, except for mental fatigue and pain, which remained unchanged.

In the first step of the mediation analyses the associations between change in physical fitness and change in global QoL (path c, total effect) were examined (Table 3). Change in peakPO was associated with change in

Discussion

This study provides further insight into mechanisms to improve QoL of cancer patients who completed chemotherapy. Similar to previous studies,5, 21, 22 the present study showed that increased physical fitness was significantly associated with improved global QoL. Furthermore, we found that this association was mediated by fatigue, suggesting that improved fitness improves global QoL by reducing fatigue. This mediation effect of fatigue is consistent with the previous finding of Schwartz¹³ who

Conclusion

Results showed that general fatigue and physical aspects of fatigue mediate the relationship between physical fitness and global QoL. We found no mediating effect of mental fatigue. Cancer rehabilitation programmes should also aim to improve physical fitness, since it may reduce fatigue and improve QoL.

Practical implications

•
Improving physical fitness in cancer patients improves their quality of life.
•
Improving physical fitness in cancer patients reduces their level of fatigue.
•
Decreasing fatigue in cancer patients improves their quality of life.
•
Physical fitness-induced improvements in quality of life can be explained by improvements in fatigue.

Conflicts of interest

None.

Financial support

This research was funded by Alpe d’HuZes/KWF fund, provided by the Dutch Cancer Society, and the research foundation of Máxima Medical Center. The contribution of L.M. Buffart was further supported by a fellowship granted by the EMGO Institute for Health and Care Research.

Acknowledgements

The authors thank all patients for participating in this study.

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Cited by (34)

Cancer-related fatigue
2018, Central Nervous System Cancer Rehabilitation
Cancer-related fatigue (CRF) is a severe and distressing form of fatigue that is often not alleviated by rest. Individuals describe a general sense of tiredness and associated functional deficits. CRF varies according to diagnosis, but patients with central nervous system (CNS) tumors may experience symptoms. Variables that influence the development of CRF are multifactorial, but may be both microscopic and macroscopic in nature. Dysfunction of the CNS to deliver appropriate responses may also result in fatigue.
Several conditions may lead to fatigue in cancer patients, such as disturbances in sleep-wake cycles, anemia, endocrinology disorders, and dietary intake. Medication effects for the treatment of cancer and its associated symptoms should also be considered. Anxiety and depression have both been associated with CRF, as have treatments such as radiation and surgery. Diagnosis is possible with patient-reported outcomes, screening tools, and clinical evaluation. Interventions may include physical and functional modalities, medications, and supportive measures. Understanding of the societal impacts of CRF, specifically as it relates to return to work and the financial implications for individuals and their families, allows for comprehensive approaches to management.
Evidence-based physical activity guidelines for cancer survivors: Current guidelines, knowledge gaps and future research directions
2014, Cancer Treatment Reviews
Citation Excerpt :
Few studies examined mediators of exercise interventions in cancer survivors. In uncontrolled trials and a cross-sectional study, exercise effects on QoL were found to be mediated by fatigue [65–67]. As another example, the effects of an 8-week mixed modality community-based group exercise and information support intervention on QoL of patients with breast cancer was mediated by exercise familiarity and self-efficacy but not by social support [68].
Physical activity during and after cancer treatment has beneficial effects on a number of physical and psychosocial outcomes. This paper aims to discuss the existing physical activity guidelines for cancer survivors and to describe future research directions to optimize prescriptions. Studies on physical activity during and after cancer treatment were searched in PubMed, Clinicaltrials.gov, Australian New Zealand Clinical Trials Registry, and Dutch Trial registry. Physical activity guidelines for cancer survivors suggest that physical activity should be an integral and continuous part of care for all cancer survivors. However, the development of these guidelines has been limited by the research conducted. To be able to develop more specific guidelines, future studies should focus on identifying clinical, personal, physical, psychosocial, and intervention moderators explaining ‘for whom’ or ‘under what circumstances’ interventions work. Further, more insight into the working mechanisms of exercise interventions on health outcomes in cancer survivors is needed to improve the efficacy and efficiency of interventions. Finally, existing programs should embrace interests and preferences of patients to facilitate optimal uptake of interventions. In conclusion, current physical activity guidelines for cancer survivors are generic, and research is needed to develop more personalized physical activity guidelines.
Effect of activities profile variations on health-related quality of life among breast cancer patients: Secondary exploratory analysis from PASAPAS study data
2020, Bulletin du Cancer
Modifier les habitudes de vie vers plus d’activité physique des femmes atteintes de cancer du sein est aujourd’hui un objectif majeur des prises en charge. L’objectif de cette étude était de tester de manière exploratoire l’impact de l’évolution du profil d’activité quotidienne sur la qualité de vie auprès de ce public.
Soixante patientes (18 à 75 ans) atteintes de cancer du sein non métastatique ont été randomisées selon un ratio 2/1 (intervention en activité physique ; contrôle) dans le cadre de l’essai clinique randomisé PASAPAS. Des analyses de régression linéaire multiples ont été effectuées afin d’expliquer les scores de qualité de vie six mois après le début des traitements adjuvants. Variables explicatives retenues : score de qualité de vie en début d’étude, trait d’anxiété, bras de randomisation, variations du temps passé dans différentes classes d’activité physique ([3-4[MET, [4-6[MET, ≥ 6 MET) et dans des comportements sédentaires.
Seule la diminution du temps passé dans des comportements sédentaires est véritablement apparue comme un prédicteur de la qualité de vie physique. La participation au groupe d’intervention est apparue comme un prédicteur de la qualité de vie mentale.
Les résultats plaident pour l’intensification de la lutte contre la sédentarité dans les objectifs de prise en charge des femmes atteintes de cancer du sein, ainsi que pour la mise place d’un accompagnement collectif encadré par des personnels compétents. Ils suggèrent également de s’intéresser à l’effet de la dynamique d’évolution du profil d’activité quotidienne sur la qualité de vie.
Lifestyle changes in breast cancer patients, by physical activity increasing, are becoming a main objective in supportive care. The objective of this study was to explore the impact of the daily activity profile evolution on the quality of life among this public.
Sixty patients (18 to 75 years) with non-metastatic breast cancer were randomized to a 2:1 ratio (physical activity intervention; control) in the PASAPAS randomized clinical trial. Multiple linear regression analyzes were computed to explain quality of life scores 6 months after the start of adjuvant therapy. Variables retained were the baseline quality of life scores, the anxiety trait, the randomization arm, the variations of time spent in different physical activity classes ([3-4 [MET, [4-6 [MET, ≥ 6 MET) and in sedentary behaviors.
Only the decrease in time spent in sedentary behaviors really appeared as a predictor of the quality of physical life. Participation in the intervention group appeared as a predictor of quality of mental life.
Results plead in favor of sedentary life style decrease as part of the objectives of care program for women with breast cancer. It also highlights the need of collective supervised sessions implemented by competent staff. This research also suggests that the dynamics of daily activity profile variations should be studied further in association to quality of life.
Physical Function and Health-Related Quality of Life in Patients with Gastrointestinal Cancer
2023, Physical Therapy and Research in Patients with Cancer
Walking capacity of Japanese patients with colorectal cancer relates to early postoperative health-related quality of life: a multi-center cohort study
2023, Physiotherapy Theory and Practice
Cancer-related fatigue mediates the relationships between physical fitness and attendance and quality of life after participation in a clinical exercise program for survivors of cancer
2022, Quality of Life Research

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Original researchFatigue mediates the relationship between physical fitness and quality of life in cancer survivors

Abstract

Objectives

Design

Methods

Results

Conclusions

Introduction

Section snippets

Methods

Results

Discussion

Conclusion

Practical implications

Conflicts of interest

Financial support

Acknowledgements

Lancet Oncol

Lancet

Semin Hematol

J Psychosom Res

J Clin Epidemiol

Clin Neurophysiol

Ann Oncol

Brain Behav Immun

Physical exercise and quality of life following cancer diagnosis: a literature review

Ann Behav Med

Exercise in cancer survivors: an overview of research

Med Sci Sports Exerc

An update of controlled physical activity trials in cancer survivors: a systematic review and meta-analysis

J Cancer Surviv

High-intensity strength training improves quality of life in cancer survivors

Acta Oncol

Long-term follow-up after cancer rehabilitation using high-intensity resistance training: persistent improvement of physical performance and quality of life

Br J Cancer

Original research
Fatigue mediates the relationship between physical fitness and quality of life in cancer survivors