Systematic review and meta-analysis of the correlates of cancer-related fatigue
- Oncology Nursing and Patient & Family Support Program, Sunnybrook Odette Cancer Centre, Toronto, Canada
- Correspondence to Margaret I Fitch
Oncology Nursing and Patient & Family Support Program, Sunnybrook Odette Cancer Centre, 2075 Bayview Avenue, Room T2-234, Toronto, ON M4N 3M5, Canada;
Implications for practice and research
Assessment of cancer-related fatigue must take into account both the physical symptoms and psychological distress.
Interventions for cancer-related fatigue must emphasise the importance of psychological distress associated with this problematic side effect.
Priority should be given to nausea/vomiting when managing cancer-related fatigue.
Future research ought to focus on symptom clusters.
Fatigue is one of the most common problems experienced by patients with cancer, regardless of diagnostic site or treatment modality. Differing from fatigue experienced by the general population, fatigue in cancer is not relieved with rest. It is pervasive and can have a profound effect on quality of life. Generally, patients with cancer develop their own approaches to deal with this challenge, but may not always initiate the most effective strategies.1 Oncology nurses are in a primary position to assist patients with cancer in dealing with cancer-related fatigue through thorough assessment and implementation of evidence-based interventions.
Oh and Seo used a systematic literature review and meta-analysis to examine the overall association of the symptom and psychological distress with cancer-related fatigue and determine which factors have a higher correlation with fatigue. Descriptions of the search strategy using MEDLINE, PubMed and CINAHL databases, study selection, quality assessment, data extraction and statistical analysis are clearly reported. Thirty studies were utilised for the meta-analysis.
All the examined symptoms (pain, dyspnoea, nausea/vomiting and lack of appetite) and psychological distress had significant associations with cancer-related fatigue ranging from medium-to-large effect sizes based on using correlation coefficients. The overall correlations with psychological distress and cancer-related fatigue were significantly higher than those of the physical symptoms. The correlation between nausea/vomiting and cancer- related fatigue was significantly higher than those of pain and dyspnoea with fatigue.
This study focuses on cancer-related fatigue given the prevalence of this problematic symptom in patients during the treatment and post-treatment phases. Virtually all patients with cancer experience it at some point during their cancer journey and it can have a profound influence on treatment adherence and the capacity to cope. The authors have described the problem clearly and made the case for conducting a systematic literature review and meta-analysis. With increasing interest in the topic, publications related to cancer-related fatigue are plentiful and there is a need to understand the overall picture created by the accumulating evidence.
The methodological approach provides the opportunity to understand a broad perspective concerning cancer-related fatigue and provides guidance for clinical practice. Understanding the multidimensionality of fatigue helps prioritise clinical assessment and interventions. The authors have clearly described the methods they utilised and the specific decision criteria for study selection and quality assessment. In the final analysis, they worked with 25 high-quality studies.
They focused on several physical symptoms (pain, dyspnoea, nausea/vomiting, lack of appetite) commonly experienced by patients with cancer as well as psychological distress (anxiety and depression). This is an important focus, as patients often experience more than one symptom and have difficulty separating the impact of one over the other.2 The focus also highlights the need to consider symptom clusters in future research and clinical practice.
The findings are reported for each physical and psychological symptom separately, illustrating how each is associated with cancer-related fatigue. However, the results also allow us to see the overall significance of the association between psychological distress and cancer-related fatigue in contrast to the distress from physical symptoms. Clearly, clinical assessment and intervention needs to incorporate this important consideration for all patients with cancer. Cancer-related fatigue can not only be conceptualised as a physical entity, but must also include the psychological dimension as well. One of the most noteworthy changes in the cancer field during the past decade is the clear acknowledgement that emotional distress is part of the cancer journey and is a common experience for many patients.3 Dealing with cancer- related fatigue may be one source of emotional distress.
This research study begins to provide guidance for developing clinical management approaches. For example, the strong association between nausea/vomiting and cancer-related fatigue implies the need to consider this physical symptoms in particultar. Patients with cancer can face significant issues around eating and maintaining energy during treatment in the face of nausea and vomiting challenges and this could add to the feelings of fatigue they experience.