Barriers to and facilitators of physical activity in adults living with and beyond cancer, with special emphasis on head and neck cancer: a systematic review of qualitative and mixed methods studies

Purpose Physical activity can improve health outcomes for cancer patients; however, only 30% of patients are physically active. This review explored barriers to and facilitators of physical activity promotion and participation in patients living with and beyond cancer. Secondary aims were to (1) explore similarities and differences in barriers and facilitators experienced in head and neck cancer versus other cancers, and (2) identify how many studies considered the influence of socioeconomic characteristics on physical activity behaviour. Methods CINAHL Plus, MEDLINE, PsycINFO, Scopus and Cochrane (CDSR) were searched for qualitative and mixed methods evidence. Quality assessment was conducted using the Mixed Methods Appraisal Tool and a Critical Appraisal Skills Programme Tool. Thematic synthesis and frequency of reporting were conducted, and results were structured using the Capability-Opportunity-Motivation-Behaviour model and Theoretical Domains Framework. Results Thirty qualitative and six mixed methods studies were included. Socioeconomic characteristics were not frequently assessed across the included studies. Barriers included side effects and comorbidities (physical capability; skills) and lack of knowledge (psychological capability; knowledge). Having a dry mouth or throat and choking concerns were reported in head and neck cancer, but not across other cancers. Facilitators included improving education (psychological capability; knowledge) on the benefits and safety of physical activity. Conclusion Educating patients and healthcare professionals on the benefits and safety of physical activity may facilitate promotion, uptakeand adherence. Head and neck cancer patients experienced barriers not cited across other cancers, and research exploring physical activity promotion in this patient group is required to improve physical activity engagement. Supplementary information The online version contains supplementary material available at 10.1007/s00520-023-07925-x.


Introduction
Cancer is a leading cause of death worldwide and approximately one-third of cancer-related deaths are caused by physical inactivity and unhealthy lifestyle behaviours [1]. Cancer survival is increasing [2], and there is an increase in the number of individuals undergoing invasive treatments and living longer with the consequences of cancer and its treatments. People living with and beyond cancer are at an increased risk of developing other chronic health conditions, and cancer survivors remain at a higher risk of their cancer recurring [3,4]. Physical activity can reduce treatment-related symptoms, decrease the development of co-morbid conditions, reduce the chance of disease recurrence and improve overall quality of life [5,6]. Although research supports the safety of physical activity during all treatment stages [7], physical activity levels often decrease during treatment and do not improve after treatment completion [8]. Patients living with and beyond cancer can suffer from a variety of physical and psychological side effects during and post cancer treatment [9] that can impede their ability to be physically active. In particular, head and neck cancer is one of the most debilitating cancers, as patients can experience difficulty breathing (dyspnoea), swallowing (dysphagia) and eating [10], and appearance-related concerns, which are either not apparent, or less severe in patients with other cancers. It is reported that only 30% of cancer patients meet recommended physical activity levels of at least 150 minutes of moderate-to-vigorous intensity aerobic activity per week [11], and 9% of head and neck cancer patients are reported to meet these recommendations [12]. However, research exploring barriers to and facilitators of physical activity in head and neck cancer is limited, and systematic reviews exploring this topic area have not included studies that have investigated head and neck cancer.
Socioeconomic factors are influential determinants of physical activity levels [13]; however, literature suggests that many studies do not consider the interactions between socioeconomic factors and physical activity in cancer patients [14]. Physical activity interventions are more likely to be successful if they are designed using theoretical underpinnings [15]. Using behaviour change theory to systematically identify barriers to and facilitators of physical activity in patients living with and beyond cancer may help to understand the determinants that influence physical activity promotion and behaviour. There have been previous systematic reviews that have explored barriers to and facilitators of physical activity in patients with cancer [16][17][18][19]. However, none of these reviews have used behaviour change theory to explore barriers and facilitators, or to understand and apply findings to physical activity promotion and practice. This systematic review aimed to explore barriers to and facilitators of physical activity in patients living with and beyond cancer, using the Capability-Opportunity-Motivation-Behaviour (COM-B) model [20,21] and the Theoretical Domains Framework (TDF) [22,23]. Secondary aims were to (1) explore similarities and differences in barriers and facilitators experienced in head and neck cancer versus other cancers and (2) identify how many studies considered the influence of socioeconomic characteristics on physical activity behaviour.

Methods
This review was conducted using internationally recognised methods for systematic reviews, and is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guidelines [24] (see Online Resource 1 for PRISMA checklist). A protocol was registered with PROSPERO in September 2021 (record number: CRD42021277345).

Search strategy
Searches were conducted across CINAHL Plus, MEDLINE, PsycINFO, Scopus and Cochrane (CDSR), for articles published from 1 January 2005 to 10 October 2022. The decision to search from 2005 onwards was to cover at least 15 years' worth of literature in the context of current health service provision. Backward reference searching was conducted using reference lists of relevant systematic reviews identified, and by searching the reference lists of eligible studies. An information specialist assisted with the development of search terms and search implementation (MM). Searches were undertaken using a combination of Boolean operators, MeSH terms, and free-text terms including 'cancer', 'neoplasm', 'physical activity', 'exercise', 'barrier' and 'facilitator' (see Online Resource 2 for the full search strategy).

Study selection
Peer-reviewed papers published between 1 January 2005 and 10 October 2022 were returned in the search. End-Note X9 reference manager for MacOS (Clarivate Analytics) was used to store references, and the online reviewing system Rayyan (Qatar Computing Research Institute) was used to aid the screening process. Duplicate records were identified using two electronic systems (EndNote and Rayyan) and by hand searching. Duplicate records were checked and removed. All titles and abstracts were screened by two independent reviewers (HD, AR/RH) and full text screening was conducted by authors HD and AR. A primary reason for exclusion was recorded at the full text stage. Any discrepancies on eligibility decisions were resolved through consensus and sometimes by consulting a third reviewer (NW/RH). Physical activity is defined as 'any bodily movement produced by skeletal muscles, that results in energy expenditure' [25]. Exercise is defined as a 'subset of physical activity that is planned, structured, and repetitive' [25]. Physical activity is used in the present review as a synonym of exercise. For the purpose of this review, a barrier was defined as a factor that impedes patients' abilities to be physically active, or impedes healthcare professionals' abilities to promote physical activity, and could include demographic, physical, social, or environmental factors [26]. A facilitator was defined as a factor that enables patients to be physically active, or enables healthcare professionals to promote physical activity, and could include demographic, physical, social, or environmental factors [26] (see Table 1 for eligibility criteria).

Quality assessment of included studies
The quality of included studies were independently assessed by authors HD and AR using the Mixed Methods Appraisal Tool (MMAT) [27]. Question 4 from the Critical Appraisal Skills Programme qualitative study assessment checklist [28] was appended as an additional question to assess recruitment strategies across the included studies. Question 4 was used as the MMAT includes a similar sampling strategy question for quantitative (descriptive) studies, but not for qualitative or mixed methods studies. The MMAT consists of two screening questions and five methodological questions with response options of 'yes', 'no' or 'can't tell'. MMAT (Version 18) does not provide an overall score from the ratings of each criterion but enables specific strengths and limitations to be critically evaluated.

Data extraction and data synthesis
A data extraction tool was created in Microsoft Excel and Microsoft Word (Microsoft Corporation, USA) and extracted study characteristics included study author, title, aim, sample size, population, outcome measure, type of activity and country. Clinical characteristics included cancer type and length of time from diagnosis (see Online Resource 3 for the study characteristics table). Socioeconomic characteristic reporting were assessed using the PROGRESS-plus equalities domains [29]. This tool is comprised of equality domains understood to influence health opportunities, including the opportunity to participate in and benefit from physical activity. Data were categorised as either collected, analysed or discussed. Data were characterised as 'collected' if relevant data were tabulated or summarised; data were characterised as 'analysed' if data were either included in the results or analysis section of the study, or included in any form of statistical analysis, or within the qualitative themes. Lastly, data were characterised as 'discussed' if data were described within the discussion section of the study, or if there was mention of any implications related to a particular characteristic.
Data were analysed and synthesised using a datadriven bottom-up approach, and Thomas and Harden's method of thematic synthesis [30] was used to inductively code, develop and generate themes from the barriers and facilitators identified across the included studies. Inductive data-driven themes were deductively categorised using the relevant domains of the COM-B model [20,21] and the TDF [22,23]. The COM-B model posits that behaviour change is dependent upon an individual possessing the capability, opportunity and motivation in order to change their behaviour [20,21]. The TDF builds on the COM-B model and consists of 14 domains that • Barriers to, or facilitators of, a physical activity intervention, or specific to those with long-term conditions other than cancer • Patients who had participated in a previous physical activity programme or intervention • Additional interventions or health promotion advice (such as nutritional or smoking cessation advice) aim to further understand the underlying barriers to and facilitators of evidence-based behaviour change [22,23] (see Fig. 1). Frequency of reporting was used to establish how frequently the barriers and facilitators were discussed across the included studies (see Tables 2, 3 and  4), and has been used to synthesise findings in a previous scoping review [31]. Comparisons were made to resolve discrepancies until the final themes were confirmed (HD, AR, NW, RH).

Results
After the removal of duplicate references, the titles and abstracts of 6181 studies were screened, of which 51 met the criteria for further review. The full texts of 51 records were screened, resulting in 33 studies meeting the inclusion criteria. An additional four studies were identified through backward searching, resulting in the identification of an additional three eligible studies and a total of 36 included studies (see Fig. 2).

Barriers
All of the barriers and facilitators identified were relevant to all of the COM-B constructs and to 11 of the 14 TDF domains (skills; knowledge; environmental context and resources; social influences; beliefs about capabilities; beliefs about consequences; social/professionals role and identity; reinforcement; intentions; goals and emotion).

Facilitators
There were no facilitators identified across any included studies that were specific to head and neck cancer.

Screening
Reports assessed for eligibility (n = 51) Reports excluded:  [24] motivation; TDF beliefs about consequences) were also frequently cited barriers by patients and healthcare professionals. Facilitators included improving education for patients, family members and healthcare professionals (psychological capability; TDF knowledge) on the benefits and safety of physical activity across the treatment trajectory (reflective motivation; TDF beliefs about consequences).

Comparison with previous literature
Consistent with previous literature [16], treatment-related side effects were identified as barriers to physical activity participation in the current review, and fatigue and pain were most frequently cited. Fatigue is highly prevalent in patients both during and post cancer treatment and persists at a higher-than-baseline level after treatment is completed, often for years [68]. Physical activity interventions have been shown to have the greatest improvement in reducing cancer-related fatigue, when compared with pharmacological treatments [69]. Consistent with previous literature, more than 50% of cancer patients receiving treatment reported pain [70], and pain continues to be a prevalent symptom in patients with cancer. Physical activity can be beneficial in reducing pain [71]; however, previous research has identified that 79% of patients reported a decrease in physical activity levels post-diagnosis [72]. Despite lack of research exploring barriers to and facilitators of physical activity in head and neck cancer, the current review identified barriers specific to head and neck cancer that were not cited across other cancer types. Treatment-related side effects that were specific to head and neck cancer included having a dry mouth or throat [46]. Previous research has reported that head and neck cancer patients ranked dry mouth or throat as the most challenging barrier, out of 36 different barriers to physical activity [10]. These symptoms significantly reduce head and neck cancer patients' abilities to be physically active and support the need for head and neck cancer to be considered a distinct population within the context of physical activity [73]. Although previous reviews exploring barriers to and facilitators of physical activity did not cite comorbidities as a barrier, the current review identified that comorbidities were a frequently cited barrier to physical activity participation. Cross-sectional research has found that comorbidities were a significant negative predictor of physical activity levels across a variety of cancer types [74]. Physical activity has been shown to reduce the risk of developing comorbidities, such as reducing the risk of developing heart disease [75]. However, as patients with comorbidities struggle to be physically active, tailoring advice and activities to the needs of each patient is required. The present review identified that lack of knowledge regarding the benefits of physical activity and lack of knowledge regarding what to do or what to advise were frequently reported barriers. These findings may help to explain why previous research has identified that some healthcare professionals did not feel confident promoting physical activity, and did not discuss the benefits with patients [76]. Conversely, a recent survey identified that 68% of healthcare practitioners reported that physical activity counselling was part of their routine practice [77]. Despite this, the current review identified that lack of time resulted in the inability for healthcare professionals to promote physical activity. Current evidence supports the safety of physical activity for cancer patients across all treatment stages [7]; however, consistent with previous literature exploring barriers to and facilitators of physical activity participation [17][18][19], fear of causing harm by being physically active was identified as a barrier in the current review. Additional fears not cited across previous reviews included fear of judgment [35,38,54], fear of germs or infection [42], fear of nausea [39], fear of fainting [39] and fear of the unknown [39]. Choking whilst being physically active was identified in head and neck cancer [46], and previous research has reported that 41% of head and neck cancer patients experienced excess mucus that caused choking [78], which may explain why this was a specific concern experienced within this patient group.

Strengths and limitations
This is the first systematic review to use the COM-B [20,21] and TDF [22,23] to identify barriers to and facilitators of physical activity in patients living with and beyond cancer, with a special emphasis on head and neck cancer. Its strengths include the application of a rigorous dual screening process for the inclusion and quality assessment of all studies, reducing selection bias and potential error. Incorporating the views of patients, family members and healthcare professionals permitted a variety of perspectives to be collected within care pathways relating to cancer and physical activity. The fact that this review only included studies conducted in middle-to high-income countries and available in English is a limitation. Evidence published in other languages may have been missed and findings may not be applicable to low-income countries. Only the following databases (CINAHL Plus, MEDLINE, PsycINFO, Scopus and Cochrane [CDSR]) were searched using the selected search terms, and quantitative evidence and grey literature were not included; therefore, some potentially relevant studies may have been missed.

Implications for practice and future research
These findings have important implications for practice. Although healthcare professionals promoting physical activity has been shown to have a direct impact on cancer patients physical activity levels [79], lack of time and lack of information or resources may prevent healthcare professionals promoting physical activity in practice. Improving education on the benefits and safety of physical activity across the treatment trajectory may improve physical activity promotion and participation. Secondly, despite this review identifying socioeconomic factors such as financial implications and social support as both a barrier to and facilitator of physical activity engagement, only a small amount of PROGRESSplus equality domains [29] were collected, analysed and discussed. This supports the findings from previous literature [14], and indicates that the influence of socioeconomic factors on physical activity participation was not frequently assessed across the included studies. As socioeconomic factors are influential determinants of physical activity levels, both researchers and healthcare professionals need to consider their influence when designing physical activity programmes, referring patients to physical activity programmes, and providing physical activity advice.

Conclusion
Despite the reported benefits of physical activity for patients living with and beyond cancer, this review identified a number of barriers to promotion and participation including side effects, comorbidities and lack of knowledge. Education and training on the benefits and safety of physical activity across the treatment trajectory should be provided to healthcare professionals, to enable them to promote physical activity to their patients. As head and neck cancer patients experienced specific barriers that impacted their ability to be physically active, exploring whether physical activity is promoted across health services for this patient group is required to understand how best to support practice. Our findings help to understand barriers to and facilitators of physical activity within a theoretical framework, which can be used to identify behaviour change techniques required to improve promotion, uptake and adherence, to reduce the detrimental effect of inactivity.