Advanced Clinical-Based Technologies for Monitoring Physical Function in Breast Cancer Survivors: Scoping Review

Introduction

Breast cancer remains the most prevalent malignancy among women worldwide, with increasing survival rates due to advances in early detection and treatment [1]. Although breast cancer mortality has declined in recent decades, as survival rates improve, attention has shifted from survival alone to long-term recovery, quality of life, and function, with rehabilitation emerging as a central component of survivorship care [2-4]. Physical function, the ability to perform physical tasks that enable daily activities and participation, is an important factor in cancer survivorship and rehabilitation and is framed within the International Classification of Functioning, Disability, and Health (ICF) [5]. Impairments in physical function after breast cancer treatment are commonly reported and include deficits in balance, muscle strength, and range of motion (ROM) [6-8]. Women undergoing chemotherapy may experience up to a 25% loss in strength and joint dysfunction [8]. Moreover, individuals surviving cancer have highlighted difficulties with balance and walking as the most common functional issues, with prevalence rates of 19% and 24%, respectively [9]. These functional limitations have been associated with poorer health-related quality of life and reduced mobility in survivorship cohorts [10,11]. At the same time, impairments in gait and balance control have been documented as potential contributors to fall risk and reduced independence in everyday life among breast cancer survivors [6]. According to the literature on cancer survivorship, over half of individuals who have undergone cancer treatments encounter physical function impairments [12].

The American Physical Therapy Association (APTA) Oncology Evaluation Database to Guide Effectiveness (EDGE) Task Force has provided evidence-based recommendations for standardized outcome measures in oncology rehabilitation. For balance assessment, the Task Force strongly supports the use of low-cost, performance-based tools such as the Fullerton Advanced Balance Scale, gait speed, Timed Up and Go, Five Times Sit-to-Stand, and the Balance Evaluation Systems Test, all rated as reliable and clinically feasible for cancer survivors [13]. In contrast, computerized balance systems such as force plates and the Sensory Organization Test (SOT) have been less recommended due to limited clinical utility and high cost, despite growing evidence supporting their sensitivity in detecting subtle postural sway and vestibular deficits in individuals with cancer and chemotherapy-induced peripheral neuropathy [14]. For shoulder ROM, the Task Force rated passive goniometry (score 4) as a recommended tool, while for muscle strength, handheld dynamometers (HHDs) (score 3) and manual muscle testing (score 2B) were endorsed as appropriate clinical measures [15]. Although these conventional methods remain the clinical standard, their limited sensitivity and responsiveness underscore the need for more objective, automated technologies capable of quantifying subtle changes in function [16,17].

Furthermore, a variety of technologies such as wearable sensors (accelerometers/pedometers), fitness trackers, smartphone apps, and advanced motion-capture systems are increasingly used to quantify physical function in breast cancer survivorship [18-22], providing objective, high-resolution data [21,22]. However, most reported applications remain in research or specialized settings with limited protocol and outcome standardization [19,22].

Accordingly, this review aims to map and characterize the use of such advanced, clinically based technologies in assessing key physical functions, including balance, muscle strength, and ROM, among individuals surviving breast cancer. For the purposes of this review, “advanced” is defined as instruments that provide automated, objective outputs beyond unaided observation or analogue readouts. “Clinic-based” denotes systems that can be operated in clinical rooms or clinically configured spaces by routine clinical staff with minimal specialist engineering support, for monitoring and assessing physical functions. These terms were selected based on their relevance within the ICF framework and their frequent association with impairment among breast cancer survivors [6,23,24]. By examining how these technologies are currently integrated into clinical practice, this review seeks to identify gaps in the existing literature and highlight areas where further research is needed.

Methods

Search Strategy

A comprehensive literature search was conducted across the MEDLINE, Scopus, CINAHL, and Web of Science databases. The initial search strategy was developed in collaboration with an experienced academic health sciences librarian (Liz Dennett) to ensure methodological rigor and comprehensive coverage. The selection of the search terms was informed by preliminary scoping searches and key indexing terms from prior reviews in oncology rehabilitation and motion analysis. The MEDLINE strategy served as the base and was adapted for syntax variations across databases. The search was conducted in multiple stages, starting with the initial search on February 2, 2024, followed by updates on June 24, 2024. Each search was repeated across the 4 databases to ensure comprehensive coverage of the relevant literature. The final search included combinations of controlled vocabulary, such as MeSH (Medical Subject Headings) terms and free-text terms related to breast cancer, physical function, and measurement technologies. The complete search strategy and related keywords are provided in Multimedia Appendix 1. In addition to peer-reviewed databases, gray-literature searches were limited to PhD dissertations. All identified articles were imported into Covidence software (Covidence Ltd) for screening. Duplicate records were automatically identified and removed by Covidence’s built-in algorithm, followed by manual verification by the reviewers to ensure accuracy.

Inclusion and Exclusion Criteria

Studies were included if they were published in English, had full-text availability online, involved adults diagnosed with breast cancer, and utilized technologies to objectively measure one or more physical functions (balance, strength, and ROM) as primary or secondary outcomes. No publication date restrictions were applied. All study designs were considered for inclusion, excluding nonoriginal articles such as study protocols, reviews, conference abstracts, books, or editorials. Additionally, studies were excluded if they involved technologies that did not meet the criteria for being both advanced and clinically based. These technologies are intended to directly assess and monitor physical functions in patients, facilitating clinical decision-making and supporting rehabilitation processes. Technologies like Vicon, for instance, were excluded if they were not designed for clinical use. To be effective in clinical settings, technologies must be easily integrable into workflows without requiring complex setups or specialized technical expertise.

Screening and Selection Process

An initial search strategy was developed in collaboration with the academic librarian to capture studies using any technology to assess physical function in adults with breast cancer. During the title and abstract screening process, it became evident that this comprehensive approach would yield several hundred eligible studies, predominantly due to the extensive literature on accelerometers and pedometers, as well as the frequent application of laboratory-based marker-based motion-capture systems. To preserve methodological rigor and avoid redundancy with existing systematic reviews and meta-analyses focused on accelerometer and pedometer studies, while ensuring a clinically actionable synthesis, an additional consultation with the librarian was conducted to refine the eligibility criteria prior to initiating full-text review and data extraction. The inclusion criteria were subsequently refined to prioritize advanced, clinically deployable technologies for point-of-care assessment of 3 core domains of physical functions. As a result, articles that used traditional technologies, such as dynamometers or goniometers, which do not meet the established definition of advanced measurement technology for the purposes of this review; nonclinic–based accelerometers and pedometers; and some lab-based motion capture systems requiring reflective markers, multicamera stereophotogrammetry, calibration routines, and dedicated laboratory infrastructure, were excluded unless the authors explicitly described clinical deployment or adaptation for real-world clinical settings. The study selection process was conducted in several stages following established scoping review methodology. Initially, two reviewers (authors MA and AW) independently screened titles and abstracts of all retrieved references against the eligibility criteria. Discrepancies between the two reviewers at this stage were flagged within Covidence for subsequent resolution. Studies deemed potentially eligible by either reviewer advanced to full-text screening, which was similarly conducted independently by the same two reviewers (MA and AW). Following both screening phases, conflicts were systematically resolved through a structured consensus process. For any study where the two primary reviewers disagreed on inclusion or exclusion, the full text and relevant eligibility criteria were reviewed collaboratively by all three reviewers (MA, AW, and MFP) in a consensus meeting. During these discussions, each reviewer presented their rationale, and discrepancies were resolved through deliberation until unanimous agreement was reached. If consensus could not be achieved through discussion, the third reviewer (MFP) served as the final arbiter. All final inclusion decisions and data extraction were completed through this consensus process, with regular meetings held among the three reviewers to ensure consistency in the interpretation of eligibility criteria and data extraction procedures throughout the review.

Data Extraction

Data extraction was collaboratively performed by the three reviewers (MA, AW, and MFP). For each included study, details regarding the study title, year of publication, country, aim, and design were recorded. Participant characteristics, including demographic information, inclusion and exclusion criteria, and recruitment methods and settings, were extracted. Information on sample size, cancer treatment details, and the instruments employed, including technological characteristics, was collected. We also recorded methodological features relevant to implementation and key findings reported by the original authors in relation to the use or outcomes of the measurement technology. The extracted data were organized and managed in Covidence for transparency and synthesis.

Data Synthesis

The extracted data from relevant studies were synthesized narratively and summarized in tabular format to provide a comprehensive overview of advanced clinic-based technologies used to monitor and assess functional outcomes in individuals surviving breast cancer. Studies were first categorized by the component of physical function assessed (balance, strength, and ROM) and then organized according to the specific measurement technology employed. For each technology identified, the corresponding data analysis methods used in the original studies were extracted and documented. This synthesis sought to deliver an analysis of the current knowledge and methodologies used to assess the included physical functions. The findings were analyzed to highlight common methodologies, instruments, and outcomes reported in the literature. This process defines how functional outcomes are commonly evaluated in individuals with breast cancer using advanced and clinic-based technologies and identifies potential gaps or inconsistencies in current practices, including variations in measurement protocols, differences in data normalization methods, and the range of technologies applied to assess similar functional outcomes.

Results

Study Identification

Initially, 3593 articles were retrieved from Medline, Scopus, Web of Science, CINAHL, and gray literature. After removing duplicates and nonrelevant gray literature (n=1508), a total of 2052 records were screened for eligibility. Following title and abstract screening, 314 articles were eligible for full-text review. Ultimately, 17 studies, each assigned a unique study ID (ranging from 001 to 017), were included for data extraction. These 17 studies, involving a total of 719 participants, were included in the review. The number of articles and methodologies utilized for reviewing, selecting, and verifying them at each stage of the process is presented in a PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram (Figure 1) [25]. While gray literature, including PhD dissertations, was considered, none met the inclusion criteria. Furthermore, the specific characteristics of the studies included in this study are comprehensively detailed in Table 1, providing an in-depth overview of their methodologies, sample populations, and key findings. Additionally, no formal quality assessment of the studies was conducted as part of this scoping review.

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Characteristics of the Included Studies

A review of 17 studies focusing on individuals surviving breast cancer revealed key insights into research locations, designs, timelines, participant stages, and objectives. The United States emerged as the most common location, hosting 7 (41.2%) of the included studies. The remaining research was conducted across a diverse set of countries, including Finland, Turkey, Portugal, Belgium, Brazil, South Korea, India, and Denmark. The review included 5 (29.4%) experimental studies, among which were 3 (17.6%) randomized controlled trials [26,31,36], 1 (5.9%) pretest-posttest experimental study [27], and 1 (5.9%) pilot intervention, [42] and 12 (70.6%) observational studies, including 4/17 (23.5%) cross-sectional studies [30,32,33,38], 3 (17.6%) case-control studies [34,40,41], 2 (11.8%) prospective observational studies [28,29], 2 (11.8%) longitudinal cohort studies [35,37], and 1 (5.9%) descriptive study [39]. The publication timeline indicated a growing interest in this area, with 11 (64.7%) studies published in 2017 or later, while the remaining 6 (35.3%) studies were published between 2003 and 2016 [37-42]. The studies aimed to assess different physical functions, with a particular emphasis on balance, strength, and flexibility related to breast cancer treatments. The objectives of the studies were varied, ranging from evaluating the effectiveness of specific interventions, such as mat Pilates [26] and myofascial techniques [36], to assessing the impact of cancer-related fatigue [30] on balance and postural control. Some studies also investigated the feasibility and usefulness of motion capture technologies for screening and assessing functional impairments [33,38,39].

Furthermore, the studies included in the review were conducted in multiple settings, predominantly within specialized medical facilities. Many studies took place in hospitals or hospital-affiliated centers. Isokinetic dynamometry using Biodex was reported mainly in hospital settings [26,28], with 1 (5.9%) study conducted in a laboratory environment [31]. Digital inclinometers were used across hospitals, rehabilitation services, and outpatient oncology clinics [34,36,37,41]. Kinect-based markerless motion capture (MMC) was implemented within oncology services spanning a medical center and an outpatient oncology clinic [33,38,39]. One (5.9%) study even extended its setting to participants’ homes or convenient community sites [42].

In terms of recruitment strategies, many studies enrolled participants through state and hospital cancer registries, clinician referrals, and ongoing treatment facilities within large urban hospitals. Researchers also leveraged community outreach by utilizing social media platforms, distributing flyers in regional cancer hospitals, and engaging with breast cancer support groups. Local media outlets, such as newspapers and radio announcements, were employed to broaden their reach. Some studies relied on word-of-mouth, emails, and telephone contacts.

The studies included in this review primarily focused on individuals surviving breast cancer, with participants aged between 30 and 75 years, and an average age range of 50 to 60 years. Among the 15 (88.2%) studies that reported participant sex, all included only female participants except for 1 (6.7%) study, which included a single male participant [35]. A total of 2 (11.8%) studies did not report any information about participant sex [26,33]. Nine (53%) of the included studies explicitly reported participants' cancer stage; all 9 enrolled individuals with stage 0 to III disease [26,30-32,35,39-42]. Among the 17 studies, 5 (29.4%) studies involved participants undergoing or having recently completed chemotherapy [27,30-32,41], and 1 (5.9%) study specifically enrolled women receiving hormone therapy [26]. Moreover, 1 (5.9%) study focused on surgical reconstruction (latissimus dorsi flap) [28]. Two (11.8%) studies included postmastectomy survivors compared to healthy controls [29,32], and 3 (17.6%) enrolled mixed-treatment cohorts [27,30,40]. In terms of sample sizes, these varied considerably throughout the studies, ranging from as few as 20 participants to as many as 100. People with stage IV cancer and cognitive impairments were generally excluded. Additional exclusion criteria, such as uncontrolled cardiovascular or musculoskeletal conditions, severe neuropathy, or inability to provide informed consent, were applied to ensure participant safety and maintain the validity of assessment results.

Reported Instruments and Key Findings on Physical Function

This scoping review found that most studies assessed physical function using a variety of outcome measures, and ROM was reported in 8 (47.1%) of the included studies [27,33,34,36-39,41]. Balance outcomes were reported in 5 (29.4%) studies [29,30,32,35,40], and muscle strength outcomes were reported in 4 (23.5%) studies [26,28,31,42]. Of these, 3 (17.6%) studies employed motion capture technologies [33,38,39], Kinect-based systems to assess upper extremity kinematics and ROM in individuals surviving breast cancer. Inclinometers were used in 5 (29.4%) studies to further quantify shoulder movements [27,34,36,37,41]. Balance assessments were another key focus: 2 (11.8%) studies employed force plates to measure postural sway in both static and dynamic conditions [30,35], while the SOT was used in another 2 (11.8%) studies to assess balance under varying sensory inputs [32,40]. In addition, 1 (5.9%) prospective study evaluated dynamic balance using a computer-based dynamic balance platform (Technobody PK 200 WL) [29].

Moreover, strength assessments were conducted using different models of the Biodex System (2, 3, 4, and 4 Pro) to evaluate isometric and isokinetic strength in muscle groups, including the shoulder, hip, knee, and wrist [26,28,31,42]. Measurements included isometric strength normalized to body weight, as well as peak torque during isokinetic contractions at varying angles and velocities. Further details on the specific tools and data analysis methods used in each study are provided in Table 2.

Discussion

Principal Findings

This scoping review mapped 17 studies deploying advanced clinic-based technologies to assess physical function in breast cancer survivors. The review identified technologies used to assess three domains, namely ROM, balance, and muscle strength, and documented variation in instrument type. These technologies were applied in varied clinical environments, primarily hospital-based and outpatient oncology settings, to measure specific aspects of physical function through structured protocols.

The studies used advanced methods to determine how people maintain their balance. These detailed assessments consistently revealed information that simpler, one-time tests often overlook. Studies using advanced balance equipment in clinical settings measured different aspects of postural control and consistently revealed information that simpler, one-time tests often overlook. SOT protocols showed balance problems when proprioceptive and vestibular systems were challenged, even though performance was nearly normal under easier conditions. This suggests that balance deficits in breast cancer survivors depend on the situation rather than affecting all balance tasks equally [32,40]. This pattern supports the clinical value of multi-condition batteries that probe sensory reweighting, rather than relying solely on single-task screens. Force plates quantify quiet-stance stability by deriving center of pressure (CoP) signals and summarizing them with standard sway metrics, typically medial-lateral (ML) and anterior-posterior (AP) excursion (range or root mean square (RMS)), total path length, mean sway velocity, and planar sway area (often a 95% confidence ellipse). These metrics capture both the magnitude (eg, excursion, area) and temporal dynamics (eg, velocity) of postural control. Notably, key ML CoP metrics, including mean velocity, mean amplitude, and RMS displacement, have been linked to higher prospective fall risk [43]. In the included longitudinal study of taxane-based chemotherapy, Monfort et al [35] used a laboratory force plate to track changes in CoP behavior during treatment; cumulative taxane exposure was associated with deteriorations in balance control, reflected by increased sway and concurrent gait alterations (shorter step length, slower walking speed). Complementing this, Wechsler et al [30] showed that cancer-related fatigue independently predicted poorer postural stability on force-plate measurements. Fatigued individuals showed compensatory stabilization strategies and greater body sway in both standing still and moving conditions. Together, these findings suggest that when clinically relevant stressors are present (eg, neurotoxic chemotherapy and fatigue), force-plate CoP metrics could be sensitive to subtle balance changes.

For measuring ROM, the review describes a spectrum of technologies. At one end are digital inclinometers, which are widely accessible but depend on the operator. At the other end are automated MMC systems, which provide less biased 3D assessments and show promising evidence of clinical usefulness. The successful application of MMC for upper extremity ROM assessment in breast cancer survivors was demonstrated across 3 studies in diverse settings, including oncology clinics and outpatient centers. This suggests these technologies have overcome initial feasibility barriers and may be ready for broader clinical implementation [33,38,39]. The strong correlation between Kinect-derived reachable workspace metrics and QuickDASH, a validated and widely used tool for assessing upper extremity disability in breast cancer survivors [44], and the system’s ability to detect side-to-side differences in functionally relevant movement zones (overhead reaching) demonstrate practical utility for monitoring recovery [33]. However, there is significant variation in how different studies measure ROM. Studies differ in whether they assess active versus passive motion, which planes or tasks they evaluate, and whether they use absolute measurements versus side-to-side comparisons. This inconsistency makes it difficult to compare studies and develop clear, evidence-based clinical guidelines. Taken together, within the bounds of the included studies, MMC appears to have promising potential for assessing upper-extremity function in breast cancer survivors.

Muscle strength was quantified with isokinetic dynamometry in controlled clinical or laboratory settings [26,28,31,42]. Systems such as the Biodex (models 2-4/4 Pro) are seen as the top choice for testing dynamic muscle strength. They control precise, preset angular velocities and capture full torque-angle-velocity relationships together with work and power outputs. These multidimensional profiles can reveal deficits in force production and velocity-dependent behavior (eg, concentric versus eccentric weakness) that are not apparent from single-value manual grades, and their test-retest reliability in musculoskeletal [45,46]. The trade-off is practical; true isokinetic testing requires dedicated equipment, space, regular calibration, and staff skilled in positioning, stabilization, familiarization, and protocol standardization, all of which limit routine deployment outside well-resourced centers. Given these constraints, many rehabilitation services rely on portable HHDs for strength assessment. Professional guidance from the APTA Oncology EDGE Task Force recognizes HHDs as an appropriate option for cancer populations, provided that clinicians use standardized patient and tester positioning, consistent lever arms, and repeated trials to improve reliability [15].

This scoping review had some limitations. First, the inclusion of solely English-language studies raised the possibility of language bias and the exclusion of relevant work published in other languages. Additionally, the review focused solely on 3 physical functions, potentially overlooking other important aspects of physical function in individuals surviving breast cancer. While multiple databases were searched, some relevant studies may not have been captured if they were published in databases that were not included in the search strategy, which can limit the comprehensiveness of the review. Finally, the variability of the included studies in design, clinical setting, treatment phase, and outcome definitions (eg, active versus passive ROM, task/plane selection, and absolute versus interlimb metrics) precluded quantitative synthesis and limits cross-study comparability. Specifically, individuals with stage IV cancer were typically excluded from most of the included studies to focus on nonmetastatic cases.

Comparison With Prior Work

A recent scoping review by Amarelo et al (2024) [47] examined the application of technological resources in cancer rehabilitation, identifying wearable devices, web-based platforms, mobile health (mHealth) apps, virtual reality, and exergaming as commonly employed tools. Their review emphasized the wide diversity of technologies and underscored the need for further research to assess their long-term effectiveness, cost-efficiency, and successful integration into clinical practice. In contrast, our scoping review narrows the focus to advanced clinic-based technologies specifically used to assess and monitor physical functions, balance, muscle strength, and ROM in individuals surviving breast cancer. By concentrating on this particular population and key physical functions, our review offers a detailed analysis of the clinical applicability, measurement properties, and limitations of these technologies. This focused approach addresses the gap identified by the previous work [47] regarding the need for more targeted research on the integration of technological tools into cancer rehabilitation practices. Moreover, our findings corroborate a previous review that recognizes force plates as effective tools for detecting subtle balance impairments [6] and Biodex systems as the gold standard for muscle strength assessment [48].

Conclusion

This scoping review synthesized current evidence on advanced clinic-based technologies used to assess and monitor 3 key physical functions, namely balance, muscle strength, and ROM, in individuals surviving breast cancer. The review found that balance assessments predominantly utilized force plates and SOT, muscle strength was assessed using various models of the Biodex isokinetic dynamometer, and range of motion was measured using digital inclinometers and MMC systems. These studies were conducted primarily in hospitals and specialized medical facilities, with participant samples spanning various treatment phases and survivorship stages. The review documented considerable heterogeneity in measurement approaches, clinical settings, and reporting practices across the included studies. These findings underline that a diverse toolkit is currently applied to measure physical function in breast cancer survivorship, but that variability in methods limits cross-study comparability. Mapping this landscape can help us prioritize targeted validation and implementation studies and inform the development of pragmatic guidance for selecting feasible, clinically useful technologies in rehabilitation practice.