A review of the literature indicated that no systematic review and meta-analysis was investigated the effects of music interventions administered to patients diagnosed with hematological cancer on fatigue management. This systematic review and meta-analysis showed that music interventions applied to patients diagnosed with hematological cancer had moderate positive effects on fatigue management. In all included studies, music interventions were administered to small sample groups [9, 10, 14, 16, 17, 36]. The small sample size was found to affect the results of the meta-analysis. In four studies, music interventions were effective in reducing the severity of fatigue [9, 10, 16, 36]; however, no statistically significant difference was found in the two of them [14, 17]. According to the results of the meta-analysis, conditions, such as fatigue and the quality of life, depression, pain, and anxiety levels related to this process were examined in the included studies. Additionally, to having an important place in our daily life, music is among the enjoyable, pleasant, and peaceful human experiences. Also, music is a powerful tool that activates brain functions. Listening to music increases dopamine, endorphin, and serotonin levels, thereby facilitating signal transmission [18, 19]. In this process, it is possible to reduce the severity of fatigue by arousing positive emotions . The results show that music interventions are an effective and non-invasive method that can be used as a holistic or complementary nursing intervention in reducing the severity of fatigue in patients with hematological cancer [9, 10, 16, 36].
Interventions, results, and population have an important place among the factors affecting heterogeneity results [38, 39]. As a result of this meta-analysis, the similarity of interventions, population, and sample size resulted in low heterogeneity (I 2 = 0%, p = 0.77). Meta-regression, sub-group analyses, or moderator analyses can be performed to determine the reason for the low heterogeneity. Since the number of studies in this meta-analysis study was less than 10, these types of analyses could not be performed [40, 41]. Additionally, meta-regression could not be conducted because variables such as the stages of hematological cancers were not given clearly. The examination of the sensitivity analysis results indicated that each time a study was excluded from the analysis, the rest of the studies were effective and made contributions to reducing the severity of fatigue [9, 10, 14, 16, 17, 36].
In this meta-analysis study, the effect of music interventions and the duration, frequency, and number of sessions on the fatigue of patients diagnosed with hematological cancer was emphasized. In all studies, passive music intervention was chosen, and instrumental, classical, and new age music types were used [9, 10, 14, 16, 17, 36]. A review of the literature indicated that research into comparing the effects of music interventions on the fatigue of patients with hematological cancer was limited. When the included studies were examined, it was found that the effect of music interventions on the management of fatigue due to hematological cancer was not associated with a certain type of music. In four of the studies, it was reported that music interventions significantly reduced the severity of fatigue [9, 10, 16, 36]; however, no significant difference was found in the two of them [14, 17].
In the included studies, the duration of the music interventions varied between 20 and 45 min, and the duration of the intervention did not affect the severity of fatigue. Although the frequency of music varied in the studies, in one study it was planned as needed , once a week , or twice . However, three of the studies did not present any information about the frequency of sessions [9, 10, 14].
The number of music sessions in the studies examined varied between 1 and 8. One session was applied in three studies [9, 10, 17], two sessions in one study , 3–7 sessions in one study , and eight sessions in one of them . While the effect size of the study in which eight music sessions were applied was found to be larger , the results of studies applying a single session were also found significant [9, 10]. The number of music sessions did not affect the results according to the data of the included studies.
When the meta-analysis findings were examined, it was found that live music interventions accompanied by acoustic guitar were frequently applied and that they had a significant effect on reducing the severity of fatigue in patients with hematological cancer. When the duration of the music sessions was compared, it was determined that 20-30-min-long interventions had a significant effect. Also, the effect of music interventions applied twice a week was high. In line with the findings, it is thought that music interventions that are 20–30 min long, are applied at least twice a week in three sessions, and are accompanied by relaxing music individualized in the patient's room will help reduce the severity of fatigue in patients with hematological cancer.
In this study, live music or music accompanied by a video, which was preferred by certified professional therapists and/or patients were used. The effects of the music interventions on the severity of fatigue in patients with hematological cancer were not associated with a certain type of music. As a result of the examination of the studies, it was found that individuals did not need to be professionals to implement music interventions and that it would be enough to only receive counseling and/or education. The music interventions in all included studies were implemented by professional music therapists [9, 10, 14, 16, 17, 36]. Valid and reliable measurement tools, such as Fatigue (FACIT-F), BFI, VAS-F, and POMS, were used to evaluate the results of the studies.
In this systematic review and meta-analysis study, it should be emphasized that the choice of music interventions by the patients and/or professional therapists or the differences in the frequency, type, number of sessions, and the duration of the sessions did not make a difference in the results of the study. Due to the wide variety of music, leaving the choice to patients causes difficulties in the selection phase. In this process, it is thought that the selection of music types or songs by therapists or researchers will lead to more accurate results. Additionally, better results will be obtained in reducing the severity of fatigue by making preferences suitable for the ethnic origins and cultural structures of the patients during the music selection process.
CONSORT flowchart has an important place in the process of evaluating the quality of randomized controlled trials. This flowchart helps to conduct the randomization process properly and reduce the risk of bias. In this process, the CONSORT flowchart was used in five of the six included studies [9, 10, 14, 16, 36]. The blinding process is difficult in randomized controlled trials, in which music interventions are applied. Therefore, none of the included studies were blinded [9, 10, 14, 16, 17, 36].
The examination of the results of the included studies indicated that no inconsistent data were found. However, there were differences in the duration, frequency, number, and types of music interventions in the studies. It is thought that determining the most appropriate duration and types of music intervention will contribute more to reducing the severity of fatigue. In line with these results, planning more studies on music interventions applied to patients with hematological cancer will be important to provide diversity in symptom management.
Strengths and limitations
The strengths of the current study include the conducting of a systematic and comprehensive literature review about fatigue in patients with hematological cancer, preparation of study data in line with Cochrane criteria, and presentation of a general overview of the effect of music interventions on fatigue in patients with hematological cancer. However, this study also has some limitations, too. These limitations include the small sample size, which consisted of six studies, the inability to conduct group analyses due to differences in the duration of music sessions, and the small sample size of the included studies in the analysis. Additionally, included studies in this systematic review and meta-analysis are considered of low methodological quality. The exaggerated effect sizes observed here are due to the lack of intention to conceal the intervention, as studies fail to blind outcome evaluators and participants to the intervention. Also, the time between the music intervention and the evaluation of the fatigue measure was not reported. More randomized controlled trials with large sample groups of patients diagnosed with hematological cancer are needed to achieve a high level of evidence.