July 12, 2021

Dr. William Breitbart

Editor-in-Chief

Palliative and Supportive Care

Dear Editor,

I have read with interest the article entitled “Exploring the efficacy of music in palliative care: A scoping review” by Nyashanu et al. (Reference Nyashanu, Ikhile and Pfende2020). With respect to the authors, I do not believe music therapy can be deemed efficacious based on the results as they state. I hereby address some issues concerning the purpose and conduct of scoping reviews.

While the introduction clearly underlines the rationale of the review, the choice of a scoping review method to determine the efficacy of music therapy in palliative care is questionable. As shown in an article by Munn et al. (Reference Munn, Peters and Stern2018) on choosing between a scoping review and a systematic review, the former maps available publications to establish the scope of knowledge, while the latter synthesizes reliable evidence to inform clinical practice and policy, including on the efficacy of a current practice. Thus, I argue that a systematic review is better suited to verify the efficacy of music therapy in palliative care with a knowledge synthesis method. In fact, efficacy is defined as “the performance of an intervention under ideal and controlled circumstances” (Singal et al., Reference Singal, Higgins and Waljee2014, p. 1), which limits the selection of articles to experimental and sometimes quasi-experimental studies. In contrast, scoping reviews typically include publication of different types (e.g., empirical studies, grey literature, reviews). It could be coherent to limit the selection of articles to experimental studies in a scoping review if the purpose was to map the extent of available knowledge, such as Duffett et al. (Reference Duffett, Choong and Hartling2013) who aimed to broadly identify randomized controlled trials to describe their method and reporting. However, assessing efficacy is not in line with the purpose of scoping reviews as the steps of this method do not allow to reach such evidence-based conclusions.

For example, scoping reviews typically don't include quality assessment of publications, as it was the case in Nyashanu et al. (Reference Nyashanu, Ikhile and Pfende2020), but this assessment is essential when formulating recommendations to guide clinical practice (Pham et al., Reference Pham, Rajić and Greig2014). Even though many studies identified in the scoping review were randomized controlled trials, the lack of quality assessment prevents from making conclusions on efficacy of music therapy in palliative care because the presence of biases that underestimate or overestimate the intervention outcomes was not taken into account (Higgins et al., Reference Higgins, Savović, Page, Higgins, Thomas, Chandler, Cumpston, Li, Page and Welch2019). Falsely concluding on the efficacy of music therapy in palliative could have the adverse effect of not developing or implementing intervention that effectively relieve suffering.

In short, this letter was written to caution readers about concluding on the efficacy of music therapy in palliative care based on findings by Nyashanu et al. (Reference Nyashanu, Ikhile and Pfende2020), and to reiterate the importance of carefully choosing between a scoping review and a systematic review. I would appreciate it if the authors shared their reasoning on the matter.