A scoping review of psychological distress instruments in women with early‐stage breast cancer during chemotherapy

Abstract Background Psychological distress is associated with worsening symptoms during the active treatment period and lower quality of life in women with early‐stage breast cancer. Many studies have indicated risk for heightened psychological distress across the breast cancer trajectory. Purpose The aim of this review is to examine the literature for instruments used to measure psychological distress among women with breast cancer during chemotherapy. Methods This study used the Arksey and O’Malley framework of scoping reviews. Two databases, PubMed & CINAHL, were searched for peer‐reviewed original articles that were published within the last ten years, included participants with a diagnosis of breast cancer stages I to III, and receiving chemotherapy, English text articles, and studies that report psychological distress measures. Findings The initial screening yielded 529 relevant studies. After applying the exclusion criteria, a total of 17 studies concerning the assessment of psychological distress during chemotherapy were retained for the analysis of variables and measures of psychological distress. The instruments used to measure psychological distress varied, with a total of 21 measures. The most frequently utilized measure was the Hospital Anxiety and Depression Scale (n = 5), followed by the Impact of Event Scale (n = 2), the Distress Thermometer (n = 2), and the Perceived Stress Scale (n = 2). Conclusion This review identified the gaps related to inconsistencies in the operationalization and instruments used to measure psychological distress among breast cancer survivors during chemotherapy. Standardization of measures assessing psychological distress, along with conceptual clarity, is essential for measuring distress in research and clinical practice.

The context of this review is focused mainly on the chemotherapy period, which is an important part of breast cancer treatment; however, it carries a high symptom burden. 5 Recent studies reported that chemotherapy can result in varied symptoms, such as anxiety, depression, fatigue, and cognitive impairment. 4,6 Anxiety and depression have been frequently examined together during active treatment, and their incidence was commonly as high as 93.6% and 25%, respectively. 7,8 Furthermore, in symptom cluster research, fatigue has consistently been prevalent alongside symptoms of distress among women treated with chemotherapy. 9,10 Also, cognitive impairment is another comorbidity that has been correlated with other symptoms of distress during chemotherapy. 6,10 These symptoms dispose BCSs to have higher risk of psychological distress, poor daily function, and reduced life quality, even after the completion of chemotherapy.
Psychological distress is a broad construct that has varying definitions in the literature. 11,12 Most of the researchers have utilized multiple terms to describe psychological distress that have commonly included anxiety, depression, and distress. [13][14][15] The American Psychological Association (APA) defines distress as "the negative form of stress in which a person experiences a negative emotional state that is usually underrecognized". 16 Furthermore, the APA has defined stress as a natural reaction to stressful life events and can cause an adverse effect if it persists for too long. 16 However, when reported in relation to cancer and cancer-related symptoms, stress is almost always synonymous with distress. Also, stress can negatively impact health, leading to immune downregulation that results in chronic health conditions such as heart disease, stomach ulcers, and renal disorders. 16,17 Thus, it is essential to assess to manage BCSs' symptoms during active therapy effectively.
The National Comprehensive Cancer Network (NCCN) recommends using the term distress to avoid the stigma associated with other mental disorders. 18 Distress is anticipated during the survivorship period of breast cancer and can be mild if patients' symptoms are not severe and do not persist long after the diagnosis. 18 The current guidelines recommend using the Distress Thermometer (DT) and Problem List (PL) scales for early detection of distress among cancer patients during each clinical visit. 1,18 The NCCN emphasized the role of clinicians in diagnosing moderate to severe psychological distress that is in line with the criteria found in the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision (DSM-IV-TR). However, there is still a gap in the literature regarding the proper identification of psychological distress among breast cancer survivors. 19,20 Prior research has reported that 20% to 50% of women had psychological distress during their diagnosis and treatment for breast cancer. 15,21 Moreover, the impact of psychological distress can extend beyond treatment into the period of survivorship. 11,14 Distress among cancer patients can be related to treatment options, including surgery, chemotherapy, and radiation; it can also result from the side effects of these therapies, such as anxiety, nausea, and fatigue. These symptoms influence breast cancer patients' survivorship and quality of life. 6,9,22 Previous reviews on psychological distress have described the impact of distress on young women and the predictors associated with distress. 19,23 Another review investigated the impacts of stress and chemotherapy on cognitive performance among breast cancer patients. 24 However, the literature shows only a single review released by the National Breast Care Center (NBCC) that emphasizes the importance of early identification of distress in women with breast cancer. 25 The NBCC's report was limited to self-reported measures of psychological distress.
The purpose of this review was to examine the literature for instruments used to measure psychological distress among women with breast cancer during chemotherapy. To our knowledge, the present review is the first one that focuses on the assessment of psychological distress during chemotherapy treatment. Understanding measurements of distress in the literature is an essential step in future management of breast cancer patients' distressing symptoms. With more reviews like the present one, clinicians and healthcare providers may better understand screening measures for psychological distress to intervene and improve quality of life for women living with breast cancer.

| METHODS
This review used a scoping review process of mapping the available literature covering this research area. 26 In this review, we used the five stages outlined in the framework by Arksey and O'Malley, which include identifying the research question, identifying the relevant studies, selecting studies, charting the data, and collating, summarizing, and reporting the result. 27 We used this framework to explore the literature on the measures of psychological distress among BCSs. We reported our findings using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Review (PRISMA-ScR). 28

| Identifying the research question
The following questions were addressed by the literature search:

| Identifying relevant studies
A scoping review was conducted to map the existing literature on the instruments used to assess psychological distress for breast cancer survivors undergoing chemotherapy. In consultation with a research librarian, studies were identified using a systematic review of the literature available on PubMed and CINAHL within the 10 years leading up to July 5, 2019. The initial search strategy consisted of the terms "psychological stress" OR "stress" OR "distress" AND "drug therapy"; OR "drug therapy" OR "chemotherapy" OR "active treatment" AND "Breast Neoplasms"; OR "breast cancer" OR "breast neoplasm" OR "breast tumor" OR "breast carcinoma." A second search was conducted using all the identified keywords, and Medical Subject Heading (MeSH) was applied when searching the databases. Also, due to the subjectivity of the term distress, and based on the description of distress, we decided to include the studies that reported psychological stress tools. Fully reproducible search strategies for each database and search are available in Supplemental File 1. Levels of distress were high at baseline (p = .0001), patients on the spiritual growth group showed elevated levels of betaendorphin immediately post intervention and at 5 months of intervention, no differences were noted in leu-enkephalin levels among groups.

| Study selection
Sanford et al. 41 United States Longitudinal study Stages I-III Before chemotherapy, mid chemotherapy, and 6 months from initial chemotherapy.
Starkweather et al. 39 United States n = 77 Longitudinal study Stages I-III T1 prior to chemotherapy T2 4 weeks after initial chemotherapy treatment, T3 6 months after initiation of chemotherapy, T4 I year after chemotherapy. Anxiety and depression levels were highest at the first day of the fourth chemotherapy session. Also, symptoms of anxiety and depression persisted throughout the chemotherapy treatment.
T A B L E 2 Instruments and operationalization of psychological distress.

Reference articles
Operationalization of distress

Distress measures
Aboalela et al. 40 ; Starkweather et al. 39 The degree to which individuals perceive their life stressful over 1 month. Bidstrup et al. 11 ; Park et al. 15 Unpleasant experience of psychological, emotional, spiritual, religious, and social factors that interfere with cancer treatment over a week. The Distress Thermometer (DT) is a 10-item scale with 0 no distress and 10 as extreme distress; Problem list (PL), is used to assess predictors of PD.

Perceived Stress Scale (PSS): is a ten item Likert Scale
(PL) is a 39 problem list items measuring six domains (practical, family, spirituality nreligion, emotional and physical domains). Responses are binary (yes, no).
Caldeira et al. 48 Spiritual distress as a state of suffering associated with impaired ability of having a meaningful life including (personal, transcendental, communal, and environmental dimensions). A questionnaire including demographical data, 40 items related to characteristics of spiritual distress according to NANDA-I. items are rated on binary response (yes, no).
The Spiritual Wellbeing Questionnaire (SWBQ). A 20 item Likert Scale including four dimensions (personal, transcendental, communal, and environmental, response rated on five-point Likert Scale).
Cheung et al. 12 Subjective symptoms of fatigue, anxiety, depression, and perceived cognitive disturbances.
Mental health literacy. The Beck Depression Inventory (BDI) is a 21-item tool used to measure the severity of depression within a week. Each item is rated on four-point scale.
A score of 17or more indicates a significant depression. The Beck Anxiety Inventory (BAI) is a 21item instrument measuring anxiety symptoms over 1 month. Each item is rated on four-point scale.
A score of 16or more indicates a significant anxiety. Cronbach's α of 0.92.
The Brief Fatigue Inventory (BFI) is a nine-item instrument measuring the severity of fatigue. Each item is rated on 11-point Likert Scale from 0 to 10. Fatigue as Moderate (4-6), Sever (7-10) were included in the study.
The Henselmans et al. 42 Psychological distress as feeling unable to concentrate, losing sleep, lack of decision making and constant feeling of pressure. General Health Questionnaire (GHQ-12). Is a 12-item scale. Responses rated on four-point scale (less than usual, no more than usual, rather more than usual, or much more than usual  [29][30][31][32][33] Three of the remaining studies were excluded because two 34,35 patients had not been exposed to chemotherapy, and one did not report a psychological distress measure as an outcome. 36 This review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Review (PRISMA-ScR). Thus, there was no risk assessment of bias across the studies in this review. 28 A flowchart of the inclusion and exclusion of the studies is illustrated in Figure 1.

| Collating, summarizing, and reporting of the results
We reported our findings descriptively using tables (See Tables 1 and 2).
We analyzed the data by utilizing a narrative synthesis approach. To review the validities and reliabilities of the identified instruments, we adapted the "Guidelines reporting the psychometric soundness of instruments". 37 The data were summarized according to the common similarities, themes, and gaps in the literature reviewed. Any modification of the content was discussed and approved by all the researchers. United States. 13,[39][40][41]46 Two were done in Japan, 38,47 two in the Netherlands, 14,42 two in Denmark, 11,45 one in Korea, 15 one in China, 7 one in Singapore, 12 one in Portugal, 48 one in Spain, 43 and one in Taiwan. 44 The inclusion and exclusion criteria are described in depth in most of the studies (n = 14). 7 The mental health literacy concept was also utilized to assess patients' abilities to recognize their psychological distress as anxiety, fatigue, depression, or subjective cognitive dysfunction. Another study examined the determinants of spiritual distress among women with breast cancer according to the NANDA-1 taxonomy II of nursing diagnosis. Furthermore, four studies were related to cognitive disturbances and distress. 12,13,38,39 Three studies investigated the psychoneurological symptoms cluster and its impact on chromosomal imbalances, systemic inflammation (C-reactive protein, proinflammatory cytokines), and neuroendocrine-immune system responses. 39,40,46 Interventional studies evaluated the efficacy and effectiveness of multiple therapies, including yoga, walking, mindfulness-based stress reduction (MBSR), tai chi, and spiritual growth groups. 14,44-46 Also among the reviewed reports was a pilot study that evaluated a home yoga program designed to improve cognitive disturbances and distress in patients receiving chemotherapy. 47 Most of the studies specified the timeframe for the measurement of psychological distress. This varied across the studies from baseline assessment, midpoint of chemotherapy, 6 months from chemotherapy and up to 2 years post chemotherapy. Detailed information on timeframe for measures of psychological distress is described in Table 1.

| Instruments for assessing psychological distress
A total of 21 different instruments were utilized to assess psychological distress (See Table 2 for determining clinically significant cases of psychological distress. 7,11,12,15,[41][42][43]47 The remaining studies discussed how higher scores are indicative of more severe distress levels. Five studies used the Hospital Anxiety and Depression Scale (HADS), which is a reliable and valid generic questionnaire developed for detecting symptoms of anxiety and depression in patients receiving care at hospitals over 1 week. Although HADS is designed primarily for assessing anxiety and depression, it was used among these studies to describe psychological and emotional distress. 14,38,41,44,47 Two studies measured psychological distress using the Impact of  Table 2.

| The concepts defining psychological distress
More than 15 concepts and constructs were utilized to define psychological distress. Studies that aimed to identify distress or its predictors mainly examined concepts of depression and anxiety. However, some studies examined psychological distress in a broader context. These studies intended to explore the associated factors, predictors, and symptoms of psychological distress and used terms that included: "distress (spiritual, emotional)," "worry," "anxiety," "perceived stress," "fatigue," "sleeping problems," "distressing thoughts," "lack of decision making," "suffering," "somatizations," "adjustment disorder," "constant pressure," "cognitive disturbances," and "unpleasant F I G U R E 2 A Conceptual map of related concepts and constructs of psychological distress in reviewed studies.
experiences that interfere with cancer treatment." The range of the reviewed domains of the instruments was between 2 and 14. The psychological and emotional domains were the most prominent. Other areas were related to social, spiritual, familial, personal, physical, biological, and functional categories. The reviewed studies' identified concepts and constructs are illustrated in Figure 2.
Among the reviewed studies, there were a few (n = 6) that utilized theoretical frameworks to guide the development of research on psychological distress. The reported frameworks were the Theory of Unpleasant Symptoms (TUS) (n = 2) 7,44 and (n = 4) the Psychoneuroimmunology Framework (PNI). [39][40][41]46 The TUS is based on the premise that the physical, conditional, and psychological factors are antecedents that impact the experience of symptoms. 44 Psychological concepts of distress within this framework included anxiety, depression, and mood disturbances. The PNI framework is based on the underlying pathways of psycho-behavioral neuroeducation-immune system processes. 39,46 Psychological distress was conceptually differentiated within the PNI framework as perceived stress, depression, and anxiety.

| DISCUSSION
A scoping review was undertaken to examine the literature for the assessment of psychological distress among BCSs. Generally, the studies measured psychological distress during chemotherapy and evaluated the effectiveness of interventions meant to alleviate symptoms of psychological distress. Within this scoping review, we identified several studies that utilized various measures for psychological distress, mainly the HADS, DT, PSS, and IES. Most of these instruments were self-rated scales. Thus, the information obtained is subject to recall bias, which affects the generalizability of the study findings.
Moreover, among the reviewed studies, there was considerable variation in the use of generic or cancer-specific instruments. The generic tools such as HADS, BDI, PHQ-8, GHQ-12, and STAI were utilized more than the cancer-specific measures. Although HADS is a well-validated tool that was initially developed to assess anxiety and depression levels among physically ill patients, 47  The reviewed studies differed in explaining the scores needed to distinguish between psychological distress present cases and no distress cases. There were studies that emphasized reporting the cutoff points of psychological distress based on the purpose of the instrument. 39,42,43 We also found studies that did not describe their method to determine high distress levels or cases of psychological distress. 38,45 For example, the NCCN recommends using a score of 4 as a specific indicator for distress cases, but we found different cutoff points reported (4, 7) for using the DT. 11,15 Thus, the diversity of interpretation methods and the significant variations in cutoff scores for determining cases of psychological distress might hinder the detection of psychological distress within the population.
In this review, reports on the reliability or validity of the instruments were scant. The reliability or validity methods were not explicitly stated. Few studies specified the procedures for examining the reliability, which included Cronbach alpha and test-rest reliability. For example, Zhang et al. 7 described the internal consistency of both the Self-rating Anxiety Scale (SAS) and Self-rating Depression Scale (SDS) as 0.93 and 0.78, respectively. However, the study did not provide the validity of both scales. Similarly, Andreu et al. 43 indicated that the internal consistency of the BSI-18 was 0.79. Test-retest reliability was used to evaluate the BAI, resulting in a value of 0.75. 12 Reporting on the validity of the instruments was also lacking.
According to Devon et al. 37 a tool is valid if it accurately reflects meaning of a particular phenomenon under study. There are several types of validation, including construct validation, face validation, and content validation. 37 Some of the reviewed studies explained earlier validation strategies (i.e., construct and content validity) within breast cancer patients. 11,43,44,46 Collectively, the reviewed studies lacked detailed descriptions of the reliability, and validity of the instruments utilized, which are necessary elements in gathering reliable and accurate data. Also, it is essential to validate the generic tools within the population of breast cancer to specifically examine psychological distress. 37 Therefore, the applicability of the generic scales needs a further validation process among breast cancer patients.
Although most of the studies defined psychological distress as depression and anxiety, usage of the term varied among the studies.

| Study limitations
This review focused specifically on survivors of early-stage breast cancer who are undergoing chemotherapy. We emphasize the need for comprehensive assessment, including different populations of all cancer types.
Furthermore, our review is limited to English text studies, and countries tend to develop measures in their native language. Our search only covered two databases and excluded literature reviews. This was done to overcome the challenges that might exist in managing the data related to the broadness of distress within literature reviews and only limit this review to include original articles that report measures of psychological distress. Furthermore, in keeping with PRISMA-ScR definition of scoping reviews, critical appraisal of quality for each included study was not part of this scoping review's methodology. 28 In this review, only a narrative synthesis method was used in reporting the findings. Therefore, the results are subject to reporting bias, as it possible that the results may lack several studies that could be relevant to the review's aim.

| CONCLUSION
This review highlights the gaps in the operationalization and instruments used to measure psychological distress among breast cancer patients during chemotherapy. We found 21 measures for assessing psychological distress and were self-reported scales. The common instruments reporting psychological distress in the reviewed studies were mainly HADS, DT, PSS, and IES. The inclusion of reliability and validity indicators for measuring distress was insufficient in the reviewed studies. Future research should incorporate detailed information on psychometric properties to increase the trustworthiness of findings.
The findings described the various conceptualizations of the term psychological distress (anxiety, stress, worry, mood disturbances, depression, fatigue, sleep problems, and cognitive distress).
Each concept and measure indicate the complexity of unifying the term psychological distress within the chemotherapy treatment trajectory. This is likely to result as patients during chemotherapy treatments deal with multiple distressing psychological symptoms such as depression, sleep disturbances, and fatigue. However, the identified concepts are unique to breast cancer patients' distress experience during chemotherapy, and this elaborate and provides insights on how these concepts enhance nurses' understanding of psychological distress.
This review concluded that the lack of a standard definition and comprehensive measure of psychological distress might limit the identification of distress in women with early-stage breast cancer. This supports previous evidence on the underassessment of psychological distress. 19,20 Therefore, additional research is needed to examine the collective meaning of the identified concepts for predicting and measuring psychological distress in a broader set of patients from other cancer populations.
This review provides valuable information for nurses, researchers and clinicians caring for individuals with breast cancer. As per current practice recommendations, early identification of psychological distress is essential in enhancing distress management in women diagnosed with breast cancer. 18 Therefore, oncology nurses should use validated cancer specific measures such as the distress thermometer.
The identified instruments and concepts may guide researchers toward developing or modifying existing instruments to manage psychological distress among breast cancer survivors.

ACKNOWLEDGMENTS
We would like to acknowledge Maggie Ansell, a Nursing and Consumer Health Liaison Librarian who assisted in generating the strategies for the literature search.

CONFLICT OF INTEREST STATEMENT
The authors have stated explicitly that there are no conflicts of interest in connection with this article.