In the Cancer Australia systematic review,2 in order to overcome the lack of integrated literature on the conceptualisation of suffering in the context of cancer, it was necessary to synthesise common elements across a number of definitions of suffering, its synonyms and symptoms. While this method allowed for a wider range of relevant sources and a broader synthesis of available information, concepts relating to suffering, such as existential and spiritual suffering and distress, are not identical. Potentially useful nuances of these concepts have therefore not been fully explored.
Many study designs were included in the systematic review, including 50 qualitative studies, 21 theoretical/opinion pieces, 20 literature reviews, 18 case reports, 13 cross-sectional studies, one combination case report/theoretical/opinion piece, one prospective cohort study and one retrospective cohort study (total 125). Levels of evidence were also not considered relevant as the goal of this part of the review was to distil definitions and concepts of suffering emerging from the range of literature.
While the inclusion of this broad range of studies was useful in conceptualising suffering, any qualitative analysis contains an element of subjectivity. Although steps were taken to reduce the subjectivity of this analysis, including the double coding of themes and involvement of the multidisciplinary working group, it is possible that a different team may have reached different conclusions.
Two measures that directly measured suffering and provided sufficient psychometric data were identified in the systematic review. Because of this small number, it was necessary to include tools that measured the various synonyms or symptoms of suffering. While these concepts are related closely to suffering, they are not identical and caution should be taken when deciding on the correct tool to use.
As a result of the large number of measures the systematic review identified (n=58), levels of evidence were not assigned to individual studies. Rather, data pertaining to the psychometric properties of individual measures has been extracted, as this was deemed the best way of presenting evidence about the appropriateness of each outcome measure. While the tools presented in this document have been validated in a cancer population and have sound psychometric properties, the majority have been validated in a research context rather than in a clinical setting.
The search for interventions to alleviate suffering focused on a list of ‘synonyms’ and ‘symptoms’ of suffering. This was necessary because of the small number of interventions (n = 2) directly targeting suffering. This strategy allowed for the consistent inclusion of any measure or intervention targeting hope, meaning, or spiritual wellbeing, and appeared the most reliable of the possible search strategies identified. However, this strategy meant that interventions were excluded where they targeted more ‘conventional’ measures of distress (e.g. anxiety, depression). Outcomes such as self-efficacy and self-esteem were also excluded, as although improvements in self-efficacy and self-esteem may be associated with alleviation of suffering, its synonyms, and/or symptoms, these variables themselves were not seen as synonymous or symptomatic of suffering.
The majority of intervention studies were randomised controlled trials or controlled trials. Levels of evidence and quality were assigned to these studies, which allowed for more in-depth analysis. Most studies were based on level II evidence, while a small number of interventions were based on level III evidence as they were assessed in pseudo-randomised controlled trials or non-randomised experimental trials. Study quality was generally strong.