Advanced practice roles of therapeutic radiographers/radiation therapists: A systematic literature review

tionally.Thisstudyaimstoestablishaninternational baselineofevidenceonAProlesinRTtoidentifyroles and activities performed by TR/RTTs at advanced level practice and to summarise the impact. Methods: A systematic PRISMA review of the literature was undertaken. Thematic analysis was used to synthesise the roles and associated activities. Six RT external experts validated the list. The impact was scrutinised in terms of clinical, organisational, and professional outcomes. Results: Studies (n ¼ 87) were included and categorised into four groups. AP roles were listed by clinical area, site-speci ﬁ c, and scope of practice, and advanced activities were organised into seven dimensions and 27 sub-dimensions. Three most-reported outcomes were: enhanced service capacity, higher patient satisfaction, and safety maintenance. Conclusion: Evidence-based AP amongst TR/RTTs show how AP roles were conceptualised, implemented, and evaluated. Congruence studies have shown that TR/RTTs are at par with the gold-standard across the various AP roles. Implications for practice: This is the ﬁ rst systematic literature review synthetisising AP roles and activities of TR/RTTs. This study also identi ﬁ ed the main areas of AP that can be used to develop professional frameworks and education guiding policy by professional bodies, educators and other stakeholders.


Introduction
Radiotherapy (RT), also known as therapeutic radiography, is a major component of cancer treatment with about half of cancer patients receiving RT. 1e6 Therapeutic Radiographers/Radiation Therapists (TR/RTTs) are health care professionals whose role includes administering radiation to the tumour whilst minimising radiation to organs at risk (OAR) and providing patient care throughout treatment planning and delivery. 7e10 The advancements in RT technology have enabled the implementation of new treatment techniques 11 and subsequently increased patient care demands. Thus, TR/RTT's clinical practice has evolved in many countries with specialisation of existing roles and emerging new roles, such as the Advanced Practice (AP) and consultant practice roles. 12 The titles TR/RTT were used in this work, however, it is acknowledged that there is no European harmonisation in the title of these professionals. The EFRS uses the title of "Radiographer" (using "Therapeutic Radiographer" to specify those practising RT), ESTRO refers to these professionals as "Radiation Therapists", but each country regulates the title and the profession differently. 13 AP roles are not performed at time of graduation (entry-level) but rather when the TR/RTTs have several years of professional experience underpinned by postgraduate education. 12,14 New flexible workforce models have been created from the resulting skills-mix (or task shifting) innovations which maximises efficiency and effectiveness to meet service demands. 15e18 This is important in RT, where a considerable gap exists between actual and optimal utilisation of RT across European countries. The goal of AP is to ensure the highest patient care with appropriate skills-mix and roles. However, conceptual and practical gaps are present because of the nature and evolution of these roles. 3,5,15,19 The definition of AP roles is confusing due to the unclear and inconsistent terms used such as "role extension", "role expansion", and "specialised practice". 20,21 Furthermore, the perception of whether a specific role represents AP varies internationally. 22e27 Moreover, AP roles can be embedded into standard practice over time. 11,20 Currently, RT departments seek patient safety with better clinical outcomes and cost-effective service. 28 Advanced practitioners in RT have clinical expertise within areas such as pre-treatment planning, dosimetry, site-specific treatment, and technical innovation. TR/RTTs practising at an AP level have a pivotal role in the patient journey, from the referral, treatment coordination, followup, and liaison with the multidisciplinary oncology team. 12 Two European benchmarking documents guide AP in RT for educational institutions and professional bodies. 29,30 Other literature from national policies includes frameworks and resources to support the implementation of AP roles. 31e36 These frameworks define advanced knowledge, skills, and competencies required for TR/RTTs to develop the scope of practice.
This literature review has adopted the definition from the multiprofessional framework for advanced clinical practice in England. 14 The framework defines that AP roles are delivered by experienced practitioners with a high degree of autonomy and complex decision-making, supported by further education (masters degree or equivalent). Moreover, it embraces the core capabilities (knowledge, skills, behaviour) that convey the extent to which practitioners can adapt to change and solve problems with high complexity and in uncertain contexts. The framework establishes 48 capabilities that allow the developing of new roles across the four pillars of AP e clinical practice, leadership and management, education, and research.
However, no AP framework based on roles and activities (with associated core capabilities and specialist competencies) exists for the profession of TR/RTTs. As a result, quality standards vary across countries, and several countries do not have professional bodies in RT, hindering the TR/RTT role development. It is crucial to have organisational governance to guarantee patient safety when professionals take on new roles through legal guidelines, regulatory and professional frameworks. 20 There is an urgent need to gather evidence from the implemented AP roles worldwide for future research with global and local significance.
This review aims to synthesise the evidence in AP roles amongst TR/RTTs' practice. Firstly, to identify AP roles and their dimensions in clinical practice areas with associated activities and tasks. Secondly, to summarise the impact of AP roles.

Methods
A Systematic Literature Review (SLR) was performed following the Centre for Reviews and Dissemination (CRD) guidance 37 for undertaking reviews in health care and following the Preferred Reporting Items for Systematic and Meta-Analyses (PRISMA) protocol. 38 A systematic search was conducted between January 2020 and March 2021.

Search strategy
A three-part search strategy (Table 1) was used based on the PICO framework omitting the definition of comparison (in this case, the standard practice) according to the methods used in previous allied health professional (AHP) SLRs. 39,40 Population was defined as TR/RTT (including common titles for the profession) 41 intervention was defined as AP (including a breadth and inclusive terminology); and outcomes was the level of practice. The final query (P AND I AND O) used on the bibliographic databases search used Boolean techniques to ensure no relevant literature was missed in the search strategy. The PRESS evidence-based checklist 42 was used to guide the electronic search strategy development, and refinements were performed through discussion and peer-reviewed by the research team consisting of international TR/RTTs and RT lecturers with different academic backgrounds and professional roles. To check the evolution and quality of published evidence on AP roles, no restrictions were applied regarding the publication year, format and study design. Also, a hand search of key RT peer-reviewed journals was conducted (including articles in press) and a literature review snowballing was performed.

Screening and study selection
A comprehensive search was performed following criteria listed on Table 2. Two independent reviewers performed the systematic search in electronic databases independently for identification. Citations were then screened for eligibility (Zotero 5.0) by reviewer one. Duplicate records were removed and where titles did not provide enough information about the study, abstracts were prescreened against the inclusion criteria. The full text of potentially relevant papers was retrieved and examined. To ensure reliability and minimise selection bias, all selected and in-doubt papers were checked independently by two other reviewers. If divergences between researchers persisted, the final decision was reached through consensus. Multiple reports of the same study were aggregated.

Quality screening
The Critical Appraisal Skills Programme 43 (CASP) tools was applied for Randomized Controlled Trials (RCT), cohorts, qualitative studies, SLR; the reporting standards from CRD at the University of York was used for studies about health service changes 44 and organisational case studies 45 ; the Sirriyeh et al. 46 tool was used for the remaining studies with diverse designs. The scores obtained were converted into three grades: good, moderate, and low.

Data extraction and synthesis
The data extraction and synthesis of the included studies consisted of two distinct phases: 1 charting study characteristics and findings using Excel (V16.60). 2 summarising AP roles evidence. The papers were thematically analysed 47 using NVIVO (V.1.5.2). All data related to AP roles was organised into themes (dimensions) and sub-themes (such as activities or tasks, and education requirements). The outcomes related to the impact of AP roles, including associated indicators and metrics, were coded using a toolkit developed by Gerrish et al. 48 and adapted for the radiography profession by Snaith et al. 49 The resulting list of AP roles and activities was validated and reorganised by six external experts representing different European countries and areas of RT (professional practice, education and training, management, research, patient advocacy).

Results
From the systematic search, 91 articles 27,50e139 published between 1999 and 2021 were deemed eligible for the review (see Fig. 1 with the PRISMA flow diagram). In the final review were included 87 studies (see supplementary File 1 for full tabular summaries of included studies). The first paper with an AP role description in RT was published more than 20 years ago in the UK. 65 The studies were conducted in 10 different countries (Table 3), the majority from the UK (35%), Canada (31%) and Australia (18%). Only five studies resulted from international collaborations. 56,73,99,126,129 Of the studies included, 41% used mixed-methodology, 30% used quantitative designs, and 29% used qualitative approaches. Most of the studies are non-experimental descriptive research designs, with only one RCT 80 and two clinical studies. 78,87 Some studies resulted from audits (11%) and service evaluations (9%). Four studies 51,66,72,82 are SLR (narrative and scoping reviews were excluded).
Forty-four per cent of the studies involved TR/RTTs acknowledged as "advanced practitioners", and the job titles were diverse between and within countries ( Table 4). The remaining studies involved TR/RTTs that performed activities or tasks autonomously or adopted a new role beyond their scope of practice, described as TR/RTT (39%), senior (10%), specialist (6%), and research TR/RTT (1%).
The majority of studies (72%) reported exclusively on the clinical practice pillar of AP, 18% included research, 18% included education, and 13% included leadership. Only 11% comprehended all four pillars of AP (Table 5).  Table 2 Inclusion and exclusion criteria.

Inclusion criteria
Focus on AP of TR/RTTs (referred to in title/keywords/text or if the reviewers considered the subject related) Peer-reviewed journal articles (original/research/regular articles) Systematic literature reviews

Exclusion criteria
Focus on standard practice of TR/RTTs (traditional scope of practice) Focus on disciplines from Radiation Sciences (radiography, radiology, nuclear medicine) but not in RT Focus on other RT professionals (e.g.: MDs, nurses, MPs) but not on TR/RTTs Focus on AP of other AHPs (e.g.: physical therapists, occupational therapists) Non-English publications Editorials, letters, commentaries, position and discussion papers, benchmarking guidelines, abstracts from conference proceedings (unless full-text article available) AHPs-allied health professionals, AP-advanced practice, MDs-medical doctors (clinical or radiation oncologist), MPs-medical physicists, TR/RTTs-therapeutic radiographers/ radiation therapists, RT-radiotherapy.
The studies were clustered into four groups (Table 6) according to the key themes and summarised in terms of research focus, methods, and findings (see supplementary File 2 for full tabular summaries of each group). Some studies were included in more than one group.

Role evaluation and development
In this largest group, most of the studies (86%) were single-role research, 19% were clinical audits, and 13% were service evaluations. The most common were single-centre studies in single-area of clinical practice, like palliative care or in one site-specific role such as breast cancer.

Task congruence
Studies investigating task congruence assessed TR/RTTs' competencies compared to other professionals (e.g., Medical Doctors -MDs: radiation or clinical oncologists) in the performance of a specific activity. The majority were single-centre studies reporting good agreement rates. 53% checked the performance of TR/RTT in specific tasks involving treatment planning (such as target delineation and autonomous simulation) and imaging of pre-treatment delivery. Other studies investigated activities related to patient care, such as treatment toxicity assessment or patient follow-up. The site-specific role more studied was breast cancer, mainly activities performed  during breast planning, such as contouring, and treatment field definition on computed tomography-simulation.

Role implementation and stakeholders' insights
The majority in this group were feasibility studies on AP (47%) with an exploratory approach using surveys, interviews or focus groups to investigate the perceptions of RT stakeholders: TR/RTTs, MDs, nurses, and medical physicists (MPs). There were also studies per scope of practice such as patient review, image review, treatment planning, and information and support.
In addition to the primary studies there were four SLR. Two reviews focused on non-specific scope of practice: one investigated the international current AP for national adaptation 51 and the other reported evidence about the impact of AP on patient outcomes and health service quality. 82 The remaining two reviews focused on specific scope of practice: image review 66 and psychosocial support. 72

Educational programmes
Education and training to support the development, implementation, and sustainability of AP roles formed the smallest group. Competency packages, frameworks, orientation and inhouse programmes (or postgraduation courses) dedicated to AP for TR/RTTs were described in these papers.

Evidence related to AP roles
This review provided insight into all the TR/RTTs' AP roles and activities, as identified across the literature. Since the AP definition is an evolving concept, some activities considered AP at the time of publication of the studies became routine practice due to the continuous change of scope of practice of TR/RTTs over time. These activities were excluded from the list of advanced activities: such as 2D imaging assessment and decision making, mould room tasks. 88,89,93,114,127,131 The thematic analysis reported activities and tasks from AP roles into seven dimensions, and 27 sub-dimensions (Table 7). Also, the advanced practitioner specialise by clinical area of practice, disease site-specific role, and scope of practice ( Table 8).
The most studied AP site-specific role was breast cancer (n ¼ 30), reporting advanced activities such as target delineation and comprehensive care interventions. The most investigated clinical area of AP was palliative care (n ¼ 24), describing activities such as referral, patient assessment, treatment prescription (Fig. 2).
The most-reported scopes of AP amongst TR/RTTs were information and support (n ¼ 24) and on-treatment review (n ¼ 15) (Fig. 3). The first includes activities such as specialised information and holistic patient support, including diverse interventions. The second includes treatment assessment and management, patient referral and orders, and pharmacological intervention.

Evidence related to the impact of AP roles
The outcomes were structured in three domains of significance: clinical, organisational, and professional. Each of these domains was divided into several sub-domains. Each sub-domain identified impact indicators (measurable and perceived) and described the outcomes with some metrics ( Table 9). The three most-reported outcomes from AP roles were: enhanced service capacity, higher patient satisfaction, and safety maintenance. Only two studies 101,128 reported negative outcomes.

Education and training of AP roles
In this review, education and training for AP in RT varied considerably (e.g., Masters in AP, Masters modules, in-house training) and often were not described. Therefore, there is no robust evidence about standardised AP programmes. This lack of strategic educational pathways at national levels directly affects   standardisation of AP roles, regulation, and protection for advanced practitioners and patients. Despite this, many studies highlight the key role of education to AP development and validation of advanced skills, specialist competencies and core capabilities.

Discussion
This SLR shows that TR/RTTs are able to develop their skills to perform AP roles with a positive impact on patient care and satisfaction. The most common roles were site-specific in breast cancer, Table 8 List of activities from TR/RTTs' AP roles by clinical area or disease site-specific or scope of practice according to included studies.
clinical area in palliative care, and also roles which involved a broader scope of practice such as information and support, and ontreatment review. These were evaluated in post-role implementation studies, mostly single-role at single-centre. Multi-centre, larger cohort studies focusing on various roles, with design of prevs post-implementation would be more informative to the community regarding the impact. Congruence studies have shown that TR/RTTs are at par with the gold-standard. Several feasibility studies investigating key stakeholders' perceptions at different settings (national, regional, or local level) support the view that role development of TR/RTT positively impact patient care. 27,55,56,62,64,65,97,108,124,129,137 Further research should focus on other stakeholders (inter-professional teams, professional bodies, regulators, employers, government agencies, etc) to gain a broader perspective.
We have used AP as an umbrella term, and the study selection was based on the research team's interpretation of AP roles from multiple perspectives and realities. The studies were analysed according to the adopted definition from the multi-framework applicable across various AHPs. 14 Advanced practitioners in RT were referred by a multitude of different titles. A considerable number of included studies did not fulfil all the requirements of the adopted definition with the description of the four pillars of AP, possibly because the roles predated the definition.
Most of the findings came from non-experimental research, especially descriptive studies or exploratory case studies with realworld data and outcomes giving information on the implementation strategies.
To date, there are reviews focused on AP for AHPs, but very few on TR/RTTs. 39,40,140 Inconsistent national implementation of AP was reported in Australia, 109,141 and in the case of diagnostic radiography, the AP roles were not successfully implemented. 142 Nursing, the pioneers of AP in healthcare, reported drivers, challenges and outcomes of this level of practice. 143e147 Also, AHPs 39,40,148 (including physiotherapists 149e151 and radiographers) 152,153 did the same. Barriers included multi-faceted challenges at various levels: organizational (lack of role clarity, management, and recognition), resources (lack of administrative assistance, cost containment issues), interactional (lack of professional support structures, medical dominance, protectionism), and role per se (complex nature of the role, working in isolation, mismatch between professional influence and authority). Besides the AP, the consultant practice (the next level beyond AP) evidenced by the role of the non-medical consultant practitioner was also explored and evaluated by nursing, 48,154e156 AHPs, 157e159 and radiographers. 160e165 Similar contexts are described across the various professions, such as lack of consistency in job description and role titles, different education preparation and supervision, ambiguity between consultant and AP levels and core profession roles that leads to different interpretations by educators and employers presenting risks that can affect the quality of patient care.

Evidence related to AP roles
Many of the advanced activities, resulted from task delegation (e.g. on-treatment review, drugs prescription), or from innovation due to technology evolution and new service models (e.g. stereotactic body RT, radiosurgery clinic) or from enhancement to improve patient experience (e.g. holistic care, survivorship support). AP roles in health care can also arise from changing the interface between services, including transfer, relocation, and liaison. 18 The review findings are consistent with grey literature. 31,33e36,166e172 However, two AP roles were not well evidenced, such as a clinical specialist in integrated cancer care (one of the proposed areas on the Australian pathway to AP) 31 and community liaison expert practitioner (one model of AP roles on the UK for provision of continuity of care between the primary, secondary and tertiary sectors undertaken within the community). 35 USA is an exception, having one publication 32 from 2007 with no studies included in this review. This suggests that AP roles are not implemented in TR/RTTs' practice in the USA 173,174 due to lack of regulation, education and structural framework.
The only AP role cross-compared between countries in the included studies was palliative care 73 with role description and educational support in cancer centres across Australia, Canada, the UK and Denmark. These findings are corroborated by an overview of "Rapid access palliative RT programmes" 175 across several countries that confirmed positive outcomes of having TR/RTTs undertaking AP roles in palliative care. 83,84,94,95,107,126 An 11-yearlong clinical perspective of this AP role supports the development of holistic care for patients with advanced cancer. 176 Some papers reported new roles and opportunities 177e188 for role development in RT, and many authors believe that this is a "season of change" for TR/RTTs due to the image-guided RT developments and adaptive RT implementation. That is, traditional roles of TR/RTTs are impractical to keep pace with these technological advancements.

Service efficiency
Enhanced service capacity Enhanced patient throughput (e.g., time between care path activities, care path total time) and efficient workflow (e.g., time audits in activity time, elimination of redundancies, time delays between activities), 52,54,55,57,59,62,69,73,75e77,83e85,90,91,93,102,104,114,116, 120,122,124e126,130,131,134,136,138 Improved resource utilization Human resources optimization (e.g., time savings of unscheduled activities for MDs, etc) and technology utilisation (e.g., #efficient bookings #inappropriate referrals, time savings for tt unit) 54,59,73,77,83e85,91,102e104,126,131,138 Quality & safety of care Improved quality Evidence-based best practice (e.g., development & compliance of guidelines/policies, increased contouring consistency), development of quality projects (e.g., adoption of new QA tools, #QA "case rounds", reports & assessments on clinical trials) 55,69,73,77,83e85,93,94,114,116,130,134,135 Maintenance of safety Consistency in practice* (e.g., error data #patient data handoffs #trends analysis, documentation for performance & process analysis), high agreement between RTT & MD tasks' performance (e.g., comparison of toxicity assessment, volumes contouring, image review), compliance rate for standards in clinical audits (e.g., patient outcomes tracking) 50 One of the omissions of the research was the clinical evidence regarding the impact on treatment outcomes, with only one study 58 reporting local control rates and treatment toxicity. This finding agrees with other authors 12,148 who identified a lack of robust data on patient outcomes. Few studies investigated paediatric-focused care, academic recognition, and costeffectiveness. This last output should also be analysed on organisational innovation with a rigorous methodology to evaluate AP roles before the implementation in daily routine. 28

Education and training of AP roles
Concerns regarding the lack of adequate postgraduation education throughout Europe for AP roles in RT has been raised, 20,189,190 besides the existing problem of lack of consistency in educational backgrounds of TR/RTTs across Europe. 3,8,13,191 According to EFRS 2020 survey 192 there are less postgraduate training opportunities on advanced treatment planning, advanced RT, and stereotactic RT than on imaging modalities in European countries. Additionally, in countries where TR/RTTs undertake postgraduation in non-RT related areas, their education did not necessarily improve the RT practice. 193 Therefore, it is necessary to implement strategic educational pathways for this level directed towards the evolving needs of RT.

Limitations
Only English papers were included therefore there is the potential that AP roles implemented in non-English speaking countries have been excluded. 194 Dissemination bias should be considered due to the lower probability of studies with nonsignificant or negative results to be published. 195 The terms used for the population "TR/RTTs" were based on the most common titles for the profession at the European level, 13,41 although the review aimed for a worldwide scope. However, the search query identified a significant portion of studies (57%) from non-European countries.
Although only one researcher performed the coding process, six external experts with different professional perspectives reviewed each list item to enhance the validity of the coded activities.
Additional studies since the SLR Since the review presented here, an additional seven articles exploring AP roles amongst TR/RTTs have been identified. 187,188,196e200 These include: an innovative AP role (sexual care after RT) 197 and a pathway for credentialing online adaptive RT role 188 in collaboration with different countries.

Conclusion
The AP roles and associated activities performed by TR/RTTs identified in this study, illustrate the main areas that could be used to develop professional frameworks and educational programmes. More than two decades of peer-reviewed evidence regarding role development and implementation of AP in RT departments can support Higher Education Institutions (HEI), or organisations aligned with an HEI or professional body, conceptualising and implementing AP roles.
A succession of positive findings over time is known, and there is a trend to demonstrate and quantify AP impact on three

Conflict of interest statement
This work was co-funded by the SAFE EUROPE project under the Erasmus Sector Skill Alliances programme [grant agreement 2018-2993/001-001].
The European Commission support for the production of this publication does not constitute an endorsement of the contents which reflects the views only of the authors, and the Commission cannot be held responsible for any use which may be made of the information contained therein.