Background

In recent years, with earlier diagnosis and better treatment options, breast cancer survival in women has increased steadily and 5-year net survival in high income countries is now 85–90% [1]. This means that millions of women worldwide are now living with, and beyond, a breast cancer diagnosis; the 5 year prevalence of breast cancer is approximately seven million globally [2, 3]. The concept of breast cancer survivorship encompasses the wider physical, psychological, social and economic issues of breast cancer [4, 5]. The transition from breast cancer patient to breast cancer survivorship brings numerous uncertainties for women [6]. The end of hospital-focused cancer treatment typically includes the loss of the safety net of active medical treatment, a resumption or alteration of former roles within and outside the home, a decline in interpersonal support and ongoing physical and psychological effects of diagnosis and treatment, such as fatigue, sleep disturbance, sexual dysfunction, urinary/bowel problems, and cognitive problems [7, 8]. However, while breast cancer care today often provides state-of-the-art biomedical treatment, it can fail to address the broader psychosocial and quality-of-life (QoL) issues associated with survivorship [9].

Psychosocial factors have been defined as any exposure that may influence a physical health outcome through a psychological mechanism [10]. Psychosocial factors can include depression and other emotional problems, psychological traits and disruptions in the social environment, all of which can compromise the effectiveness of health care and adversely impact breast cancer survivors’ return to good health [9]. Major depression, for example, is substantially more common in people with cancer than the general population and mostly goes untreated in the outpatient setting [11]. There is some evidence that psychosocial factors are associated with impairments in QoL in breast cancer survivors [8]. High social isolation and lack of social support have been reported to be associated with a lower QoL in breast cancer survivors [12]. In contrast, personality attributes such as optimism (i.e. general expectancy for positive outcomes) and use of active coping strategies such as problem solving, identifying benefits in the experience and expressing cancer-related emotions are all associated with greater psychological adjustment and an improved QoL [13].

Some studies have indicated that breast cancer survivors have a significantly lower QoL, including lower physical, functional, emotional and social well-being compared to control-matched healthy populations and experience clinically relevant restrictions in several QoL dimensions 10 years after diagnosis, with restrictions in role, cognitive and social functioning and fatigue increasing over time [12, 14]. While other studies have found that 10 years after diagnosis, many women report having a new meaning to their lives and healthier lifestyles, with long-term survivors having similar or improved QoL levels when compared to age-matched controls who have never had breast cancer [15, 16]. To inform survivorship care planning, it would be valuable to better understand which psychosocial factors are associated with improved or worsened QoL in breast cancer survivorship. Such an understanding would inform evidence-based psychosocial care and enable the development of targeted interventions to enhance QoL and reduce long term psychological and physical morbidity [6, 17]. This scoping review, therefore, examines the evidence on the influence of psychosocial determinants on QoL in breast cancer survivors.

Methods

This scoping review seeks to identify the current literature published in this field, examine how the research was conducted and identify the key factors related to this topic and gaps in knowledge [18]. The scoping review framework of Arksey and O’Malley [19] and later advanced by Levac, Colquhoun [20] was used to guide the current study. This framework includes five stages: (1) identifying the research question(s); (2) identifying relevant studies; (3) study selection; (4) data extraction; (5) collation, summarising and reporting the results [19].

Identifying the research question

This scoping review was developed to describe the nature, number and scope of published research articles measuring the association between psychosocial determinants and QoL in breast cancer survivors.

Identifying relevant studies

A systematic literature search of the databases, PubMed, Embase, PsycINFO, and CINAHL was conducted of all articles published between 01/01/1998 and 31/12/2018. The electronic search strategy included MeSH headings, key words and their derivatives “breast cancer, survivor, quality of life” (Appendix). The terms and the search criteria were developed and tested with a medical librarian. All articles were downloaded into Endnote and duplicates were removed.

Study selection

The titles and abstracts of all identified studies were screened by an independent team of reviewers. One reviewer independently applied the inclusion criteria (Table 1) to each abstract and a random sample of 75% of the abstracts were reviewed independently by a second reviewer. The review team met to compare screened abstracts and any differences were resolved through consultation with a third reviewer.

Table 1 Study inclusion and exclusion criteria
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The inclusion criteria were then refined and a more detailed set of criteria was developed for the full text review process (Table 1). The breast cancer survivorship definition was refined to only include women who had completed their hospital-focused breast cancer treatment e.g., women had to be post-surgery, chemotherapy and radiotherapy treatments (if applicable). The criteria for the QoL measure was refined to include only validated measures of overall QoL (e.g. FACT-B, EORTC QLQ-C30) [21, 22]. At least one of the psychosocial determinants measured had to be potentially modifiable (e.g. depression, social support). Two reviewers independently reviewed the full texts of all the identified abstracts using these more detailed inclusion criteria. The reference lists of eligible studies were also reviewed to identify any further studies that had been missed in the electronic searches.

Data extraction

After reading the full-texts of each study to be included in the review, two researchers independently extracted the following data: author(s), year of publication, study design, study location, participant characteristics, time period, psychosocial determinant(s) and how they were measured, QoL outcome and how it was measured and the main findings and any adjustments for covariates. Data was initially extracted from the first 5 studies and compared by the two reviewers to ensure consistency.

Collating and summarising the data

The data from the included studies was collated by both psychosocial determinants and QoL measures to provide both a descriptive and numerical summary of the findings and to answer the following four research questions;

  1. 1.

    What are the main psychosocial determinants of QoL in breast cancer survivors that have been investigated to date?

  2. 2.

    What are the most frequently used measurement tools to assess QoL in breast cancer survivors?

  3. 3.

    Which psychosocial determinants measurement tools were used and how frequently were they used per individual QoL measures?

  4. 4.

    What is the influence of these psychosocial determinants on QoL in breast cancer survivors?

Results

Study population

The study selection process is outline in Fig. 1. The four databases yielded 7516 citations, which reduced to 6071 after removing duplicates. Of these, 58 full-texts were deemed potentially eligible and reviewed in full text. Of these, 33 studies were eligible for inclusion in this scoping review.

Fig. 1
figure 1

PRISMA diagram of selection of studies

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The majority of included studies (n = 26, 79%) employed a cross-sectional design; the remaining 7 studies (21%) assessed and compared QoL at various different time points post diagnosis e.g. short term at 6, 12 and 18 months [23, 24], medium term 2–4 years [25,26,27] and longer term 5–13 years later [13, 28]. Most studies were conducted in the United States (n = 22, 67%), with the remainder from China (n = 3, 9%), Germany (n = 2, 6%), and single studies in Australia, Taiwan, Malaysia, Japan, Korea and Austria respectively. Sample size ranged from 51 to 2671 participants; the average was 418 [29, 30]. The average age of participants was mid-40s to mid-50s, but ranged from 18 years to 96 years. The time period since completing breast cancer treatment varied greatly; some studies assessed the psychosocial determinants of QoL 6 months to 1 year post-treatment [28, 31], while other studies included participants who completed treatment up to 35 years previously [32].

Identifying psychosocial determinants of QoL in breast cancer survivors

The eligible studies reported on 16 possible psychosocial determinants of QoL (Table 2). The most prevalent psychosocial determinants investigated were social support (investigated in 14 studies), depression (7 studies) and future appraisal and perspective (7 studies). Five studies assessed coping, optimism and stress determinants and 4 studies assessed spirituality. Three studies looked at anxiety, confidence and self-efficacy and impact of events. Two studies investigated post-traumatic growth and there were single studies for positive and negative affect, cognitive symptoms, work limitations and health care system factors.

Table 2 Psychosocial determinants of QoL in breast cancer survivors
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QoL measures

There were 12 different validated QoL outcome measures utilised by the various studies in the scoping review (Table 3). The Functional Assessment of Cancer - Breast Cancer (FACT-B) was the most frequently used QoL measure (13 studies) [23,24,25,26, 30, 33, 35, 38, 41, 47,48,49, 54]. Two studies applied the Functional Assessment of Cancer Therapy – General (FACT-G), without the Breast Cancer Subscale (BC Subscale) [31, 42]. The SF-36 was used in 8 studies [27, 33, 36, 37, 47, 50, 52, 53]. The EORTC QLQ-C30 was used to assess QoL in 6 studies [28, 29, 43,44,45, 56] and EORTC QLQ-BR23 in 3 studies [29, 42, 44]; with 2 of these studies using both the EORTC QLQ-C30 and QLQ-BR23 [29, 44]. Three studies applied the Quality of Life Index Cancer Version (QLI-CV) [32, 39, 51]. The remaining QoL measures were used less frequently (≤ 2 studies). Seven studies (21%) used more than one measure of QoL as an outcome [29, 33, 41, 42, 44, 47, 52].

Table 3 Frequency of QoL measures
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Frequency of psychosocial determinants measurement tools per individual QoL measures in breast cancer survivors

A range of different measurement tools were used per psychosocial determinant (Table 4). There were 10 different measures of social support used in 14 studies, with the Medical Outcomes Survey (MOS) Social Support Survey and the Interpersonal Support Evaluation List (ISEL) used most frequently (3 studies respectively). The majority of measurement tools were used in only 1 or 2 studies. Table 5 presents the frequency of the individual psychosocial determinant measures per individual QoL measure. The 14 studies that measured the influence of the determinant social support employed 10 different measures of social support and 7 different measures of QoL. The MOS Social Support Survey was used to measure social support in 3 different studies but only 2 of these studies used the same QoL measure [23, 33]. Similarly depression was measured by 4 different measures and its influence was assessed using 4 different QoL measures. While future appraisal and perspective was measured in 7 studies using 8 different measures and 6 different QoL measures; only 2 studies used the same measure for the determinant (uncertainty in illness) and QoL [32, 51].

Table 4 Description and frequency of psychosocial measures
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Table 5 Frequency of psychosocial determinant measures per individual QoL measure
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Assessing the influence of the psychosocial determinants on QoL in breast cancer survivors

Among the studies that investigated social support, the general conclusion was that low perceived support was associated with a worse QoL [35, 41, 56] and higher levels of support were associated with better QoL [13, 23, 28, 32, 34, 37, 38]. Three studies found that the influence of social support on QoL varied by the type of support e.g. appraisal, belonging [36, 39]. Only 2 studies found no association between social support and QoL [26, 33].

For depression, 6 studies showed an inverse relationship with higher/lower levels of depression associated with a lower/higher QoL [23, 24, 26, 31, 42, 44] and one study found no association [43]. Out of the 7 studies that investigated future appraisal and perspectives, fear/worry about cancer recurrence was associated with a lower QoL in 4 studies [26, 29, 30, 52]. Higher uncertainty about illness was found to be associated with a lower Qol in 2 studies [32, 51] and appraisal of illness was also shown to mediate the influence of concerns and optimism on women’s QoL in one study [38].

The 5 studies that looked into coping generally found that the most relevant aspect of coping was the type of coping strategy one used, with disengagement, self-distraction, keeping to self and wishful thinking all having a negative association with QoL [28, 41, 47]. In general higher utilisation of active coping and lower utilisation of passive coping were positively associated with QoL [23, 25, 41]. Four of the 5 studies that assessed the role of optimism on QoL found that higher levels of optimism were positively associated with QoL [13, 23, 28, 50]; the remaining study was null [38]. All 5 studies that investigated stress found that greater psychological stress, symptom distress and life burden were associated with a lower QoL [33, 35, 38, 47, 54].

The 4 studies that examined the association between faith or spirituality and QoL had mixed findings. One study found that women with greater spiritual beliefs were more likely to have a lower emotional QoL [26], and another study reported that spiritual struggles were associated with lower QoL [48]. The other 2 studies concluded that higher rates of engagement with faith and spirituality had a positive impact on QoL [23, 49].

For the 3 studies that assessed anxiety, 2 studies reported that higher anxiety was associated with a lower QoL [31, 45] while the remaining study found a null association [43]. In 3 individual studies higher confidence, self-efficacy and self-esteem were each found to be associated with higher QoL [13, 35, 39]. Higher frequency of intrusive thoughts in 2 studies [23, 37] and a perceived negative impact of cancer in 1 study were associated with a lower QoL [53].

Two studies found that higher scores for posttraumatic growth were associated with a higher QoL [27, 54]. While higher scores on negative affect and cognitive limitations were found to be associated with a lower QoL [43, 46]. Work limitations were reported to have no significant impact on QoL [43]. The one study on health care system determinants found that a positive patient-doctor relationship was associated with better psychological well-being, while diagnostic care delay was associated with lower physical well-being in some ethnic groups [33].

Discussion

This review confirms that there are numerous psychosocial determinants that are associated with QoL in breast cancer survivors. The psychosocial determinants investigated most frequently were social support, depression and future appraisal and perspective. There was less research undertaken on societal determinants, such as healthcare system factors, work limitations etc. In general, across all the 33 articles included in this review, a higher level of a positive influence and a lower level of a negative influence of a psychosocial determinant was associated with a better QoL e.g. higher social support and lower levels of depression were found to be associated with a higher/better QoL. There were some determinants such as spirituality and coping were the influence on QoL was mixed or it varied, depending on which aspect of the determinant was measured e.g. type of coping strategy; but these determinants were also less commonly investigated.

This review also identified a range of gaps and limitations in the current literature and areas for further research. The majority of studies were cross-sectional and assessed the influence of psychosocial determinants on QoL at a single point in time. It is possible that the influence of psychosocial determinants on QoL may vary over time. A US study of breast cancer survivors found that when worry about recurrence increased over time (4 years after diagnosis), women were more likely to report a decline in emotional well-being. On average, there was a gradual lessening of worry as the years of survivorship increased, but some women reported greater worry at 4 years than they did shortly after primary treatment was completed [26]. The majority of the studies were undertaken in North America and the findings may not be transferable to other countries, with differing health care systems and cultures.

There is also considerable variation in the type of measures being used to assess both QoL and the individual psychosocial determinants across studies. There were 12 different QoL measures utilised across the 33 studies. Some of the QoL measures were breast cancer specific (FACT-B), some were cancer focussed (though not specific to a particular cancer; EORTC QLQ-C30) and some were generic (SF36) and hence may not have focussed on the same aspects of QoL aspects. Thus findings may not be comparable. A systematic review of QoL instruments in long-term breast cancer survivors identified only three instruments (QLACS, QLI-CV, QOL-CS) that evaluated all four domains of QoL (physical, psychological, social and spiritual) [107]. These instruments were only used in 5 studies in the current review (Table 3). Similarly, this review identified that on average 6 different measures were used per psychosocial determinant, making comparability of findings difficult.

While the findings provide evidence of a relationship between individual psychosocial determinants and QoL, they are not conclusive. Across the 34 studies there was only ever a maximum of 2 studies where results could be directly compared and this was only feasible for 6 determinants; social support, anxiety, coping, spirituality, optimism and future perspectives and appraisal. (Table 5) The clinical relevance of the possible effects of the determinants on QoL is also difficult to interpret. Differences in QoL should be compared to the minimal important difference for the various QoL measures, if known e.g. estimated to be in the range of 3–8 points for the FACT-B [108, 109]. It is also possible given the breadth in definition of a “psychosocial determinant”, that there are a range of other determinants whose influence on QoL has yet to be measured in studies e.g. motivation, goals. A recent systematic review identified that cancer may impact patients’ life goals and life goal disturbance may be related to poorer psychological outcomes but further studies are required [110].

This is the first scoping review of the psychosocial determinants of QoL in breast cancer survivors. However there were some limitations to this review process. It is feasible that despite an extensive search of multiple databases, some relevant papers may have been missed. Not all abstracts were screened by two independent reviewers; 75% were screened. However the adaption of the inclusion/exclusion criteria by the two independent reviewers as part of the scoping review iterative process allowed for a more focused review by alleviating any potential ambiguity, given the broad research question [20]. There was also no quality appraisal or meta-analysis of the included studies undertaken, but again is not deemed to be part of the scoping review process [19].

Recently there has been an emphasis on developing more patient-centered care in breast cancer survivors and using an individual’s psychological needs as a guide for psychosocial treatment selection rather than their diagnostic or medical treatment [111]. Understanding the influence of psychosocial determinants on QoL in breast cancer survivors potentially helps to enable the development of more personalised and tailored intervention strategies and support services to reduce long term physical and psychological morbidity. The identified psychosocial determinants can be mapped to evidence based psychosocial treatments such as Cognitive and Behavioral Cancer Stress Management to provide patients with skills to live well with breast cancer and/or improve QoL [112].

Conclusion

This review has identified several psychosocial determinants of QoL in breast cancer survivors. The overall consistency of the associations found between the various psychosocial variables and QoL, regardless of the measures used, provides a reasonably clear picture of the influence of individual psychosocial determinants on QoL in breast cancer survivors. The fact that these associations do not depend on the specific measures used adds validity to the findings. However this review has also highlighted a clear need to standardise measures of both QoL and individual psychosocial determinants, potentially through expert consensus groups, in order to be able to evaluate the impact of psychosocial determinants on QoL systematically and to compare results across studies. Further research also needs to be undertaken in health care settings, outside of the USA; given that psychosocial determinants and QoL itself may in fact be influenced by the organisation and availability of follow-up clinical and supportive care. Future studies should also use a prospective or longitudinal design to monitor change and understand the complexity and variety of influences on QoL long-term. By improving the quality of evidence on this topic there is the potential to also improve the quality of follow-up care in breast cancer survivors.