Comparing the experiences of cancer survivors living with sleep disturbances between differing levels of psychological distress: a qualitative study

Abstract

Background

Psychological distress often co-occurs with sleep disturbances; but the specific mechanisms linking the two remain unclear. A qualitative study explored perceptions and factors associated with sleep disturbances in cancer survivors between patients with varying levels of psychological distress.

Methods

Thirty-three Cantonese speaking mixed type cancer survivors were recruited from a community cancer care program. Participants that scored > 5 on the Pittsburgh Sleep Quality Index and had non-clinical or borderline to clinical levels of psychological distress underwent semi-structured interviews. Interviews were analyzed using grounded theory.

Results

Common triggers of sleep disturbances included unresolved treatment side-effects, intrusive thoughts about cancer and fear of cancer recurrence or progression, poor sleep hygiene and a lack of routine. Those with higher levels of distress exhibited more worry about recovery after cancer. Further, they engaged in thought suppression and experienced meta-worry about negative emotions and worry of poor sleep impacting recovery and cancer progression. They commonly exhibited high sleep reactivity and were observed to have limited social support. In contrast, those with low distress adopted better adaptive mechanisms, including a changed commitment to prioritizing health and positive reappraisal of their recovery progress. Self-distraction was used to cope with sleep disturbances and they had fewer expectations of good sleep quality.

Conclusions

Findings provided insights into the suitability of interventions for patients with sleep disturbances. Interventions targeting maladaptive emotion-focused coping may be more effective in addressing sleep disturbances in cancer survivors with higher distress. Interventions adopting a stepped-care approach may be advantageous in managing sleep disturbances by catering for varying levels of distress.

Introduction

Sleep disturbance is a highly prevalent symptom experienced by cancer patients; pooled prevalence reports have indicated that 60% experience sleep disturbance during active treatment and 59.7% more than 3 months post-treatment [1]. Furthermore, high levels of sleep disturbance were observed to persist in 30% of cancer survivors for two years after treatment completion [2]. The negative impact of sleep disturbance extends beyond quality of life [3]; long-term sleep disturbance has been linked with poorer health consequences, including increased morbidity and mortality generally [4], as well as adverse effects on tumor growth and cancer progression in cancer patients specifically [5].

Psychological distress is another prevalent condition affecting cancer patients, and has been linked to sleep disturbance [6]. Psychological distress has been reported in one in two cancer patients (52%) across multiple cancer groups [7]. The highest levels of psychological distress are typically observed during cancer diagnosis and treatment periods [8, 9], and while psychological distress shows a decreasing trend after cancer diagnosis [10], 12–19% of women report experiencing no declines in chronic distress after completing breast cancer treatment [11,12,13].

Significant overlap of sleep disturbance and psychological distress is reported in cancer survivors. Depressive symptoms have been identified as a risk factor for sleep disturbance in a systematic review and meta-analysis examining breast cancer survivors [14]; and in mixed type cancer patients at two years post-treatment [15] and at 9 years post-diagnosis [16]. Likewise, anxiety was associated with sleep disturbance in long-term prostate cancer survivors [17]. Longitudinal studies have further highlighted the lasting impact of psychological distress on sleep disturbance across various cancer types, underscoring the complex relationship between the two. Initial high levels of depressive and anxiety symptoms measured within 4 months of a new diagnosis of breast cancer were associated with high levels of chronic sleep disturbance up to one year post-diagnosis [18]. Greater increases in depression predicted subsequent increases in sleep disturbances during the first year of diagnosis in ovarian cancer patients [19], and baseline depressive symptoms predicted persistent sleep disturbances during two years post-treatment [2]. Conversely, lagged effects of poor sleep increased both fatigue and subsequently depressive symptom levels in ovarian cancer patient during treatment, suggesting the relationship to be a two-way influence [6]. Worsening anxiety among colorectal cancer patients was found to be associated with increasing sleep disturbance up to 10 months following diagnosis [20]; and baseline trait anxiety measured before treatment predicted lower sleep quality in breast cancer survivors at 2 year follow-up [21].

However, there are instances where sleep disturbance experienced by cancer survivors prevails without anxiety or depression. For example, depression and anxiety symptoms are associated with sleep disturbance near diagnosis and treatment [22,23,24], but the effect of anxiety on sleep disturbance was not found to sustain longitudinally after treatment [2, 19]. Another longitudinal study found anxiety, but not depression, predicted sleep disturbances in breast cancer survivors at 2 years post-chemotherapy [25]. As a result, the relationship between sleep disturbance and psychological distress cannot be assumed to be mutually reinforcing in cancer survivors.

While several frameworks and models have attempted to conceptualize the psychological mechanisms involved in the development and maintenance of sleep disturbance in general populations, variations in mechanistic properties between proposed models leave the exact nature of the relationship between sleep disturbance and psychological distress, particularly in the context of cancer survivors, unclear. For instance, Spielman et al. [26] proposed that the presence of anxiety and depression disorders may serve as a precipitating factor that triggers the onset of insomnia, while Espie [27] and Harvey [28] suggested that a combination of selective attention towards worries about sleep and dysfunctional sleep-related beliefs, such as negative consequences of poor sleep, leads to heightened arousal and psychological distress, which ultimately results in sleep interference.

Given that the relationship between sleep disturbance and psychological distress is unclear, exploration of the relationship between the two is needed to build a conceptual framework for the development and maintenance of sleep disturbance in a cancer setting. Sleep disturbance is likely to be affected by others factors such as employment status [2, 29], lasting treatment related side-effects including pain and hot flashes [14, 19, 30], and disruptive chronobiological effects on circadian rhythms [31] as a result of chemotherapy. However, given that different factors may impact sleep quality at different times across the trajectory of cancer survivorship, it is important to understand the context to which such factors may trigger or perpetuate sleep disturbances in order to understand the mechanisms behind sleep disturbance in the presence or absence of psychological distress. For example, disruptions of circadian rhythms resulting from chemotherapy are likely to be less impactful towards the end of treatment [32] and psychological distress is likely to play a larger role in perpetuating chronic sleep disturbances after treatment completion [2]. Identifying the differences in the experiences of sleep disturbances in cancer survivors between different distress levels through qualitative analysis can help to clarify these mechanisms. Existing qualitative studies have predominantly focused on the contributing factors and negative consequences of sleep disturbance [33,34,35,36,37,38] without exploring the potential underlying processes of sleep disturbance, such as the perception of sleep, which has only been covered by a handful of qualitative studies [39,40,41,42].

We report a qualitative study implemented to provide insight into the differences in experiences of sleep disturbance between cancer patients with varying levels of psychological distress in order to illuminate factors involved in developing and maintaining sleep disturbance.

Methods

Design

Given that psychological distress and perceptions of sleep are known to contribute to sleep disturbance, a qualitative study was conducted to investigate the variations in patient responses across different levels of distress with the aim of gaining a better understanding of the underlying processes leading to the development of sleep disturbance. Using a descriptive-interpretive approach, we compared the lived experiences of cancer survivors with sleep disturbance between those reporting non-clinical levels of psychological distress and those reporting borderline to clinical levels of psychological distress.

Participants

Purposive sampling was used to select cancer survivors who had attended a community-based multidisciplinary cancer care program between September 2022 and August 2023. Ethics approval was granted by the Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster (No: UW 22–595). Eligible patients were Cantonese and Mandarin-speaking Chinese patients aged 18 years or older, diagnosed with cancer without metastatic disease. Given that sleep disturbance was observed to persist in 30% of cancer survivors for two years after treatment completion [2], the qualitative study also aimed to capture experiences of sleep disturbances for patients that had completed curative primary and adjuvant treatments within two years, during the early phase following treatment completion. Patients were assessed for sleep disturbances and psychological distress using the Pittsburgh Sleep Quality Index (PSQI) [43] and the Hospital Anxiety and Depression Scale (HADS) [44]. Patients that either have 1) poor sleep (PSQI > 5) and non-clinical levels of anxiety or depression (HADS ≤ 7) 2) or poor sleep (PSQI > 5) and borderline or clinical levels of anxiety or depression (HADS ≥ 8) were identified as eligible participants. Patients that were regularly seeing psychiatric services, or attended workshops or interventions targeting sleep or psychological distress were excluded. Patients with linguistic or intellectual difficulties or receiving active adjuvant treatment (excepting hormonal treatment as it is often used as adjuvant therapy to reduce the risk of cancer recurrence and is typically taken for at least 5 years) were excluded.

Procedure

Patients were approached after attending the community cancer care program and were asked if they would like to take part in an interview on their experiences of sleep disturbance. Willing participants completed a screening interview and were recruited if they met eligibility criteria. Written consent was obtained, and each participant was scheduled to complete an in-depth, semi-structured, recorded interview of approximately 45 min in duration that was either conducted via a phone call or Zoom, a digital video conferencing platform. The interviewer (J.C.) was a doctoral candidate with a specialization in psycho-oncology and behavioral health. The semi-structured interview guide included questions regarding the sleep disturbance experience before and after cancer diagnosis, factors perceived to impact sleep quality, strategies that were used to manage sleep disturbances, thoughts and feelings that arise when poor sleep occurs, beliefs, attitudes and expectations towards sleep, perceived need to seek professional help in managing sleep disturbance and understanding of sleep hygiene (Appendix A). To minimize the burden on the participants, participants were not asked to review the transcripts. To ensure that the meanings attributed to the participants' responses accurately reflected their intended message, the interviewer repeatedly reconfirmed their understanding and interpretation of the responses throughout the interviews. This involved summarizing key points and confirming with participants to ensure their responses were correctly understood in real time. The sample size was determined by data saturation within each of both groups, where additional data did not lead to any new emergent themes [45].

Data analysis

All digitally recorded interviews were transcribed verbatim in Cantonese/traditional Chinese. Transcripts were then analyzed and coded using the grounded theory technique [46]. Data was subjected to constant comparative analyses. The analytical process was based on immersion in the data and repeated sorting, coding, and comparison. Each interview was examined line-by-line and subsequently sorted into code components by two coders (J.C. & Y.S.). Each code component from both coders was compared to each other to ensure that the codes were mutually exclusive and to identify any possible connections, which were then clustered to form broader categories or themes. The NVIVO software, designed for organizing and processing qualitative data, was used to facilitate data coding and analysis. The properties of the studied concepts were then hierarchically derived [47]. Following systematic organizations of code components and themes, the data were cross-checked by senior team members (W.W.T.L. & D.W.L.N.) experienced in qualitative research to increase the validity of theoretical constructs through repeated discussions. All analyses were performed in the original language of Cantonese.

Results

Participants

Thirty-three cancer patients consisting of breast, gynecological, head and neck, colorectal and lymphoma cancer participated in the study. On average, the patients were diagnosed 15 months prior to the time of recruitment. All patients presented with clinical levels of sleep disturbances (PSQI > 5), of whom 13 reported borderline or clinical levels of psychological distress (HADS ≥ 8), and 20 reported non-clinical levels of psychological distress (HADS ≤ 7). Patients in the non-clinical and borderline to clinical distress group reported a global PSQI score of 9.75 ± 3.36 and 11 ± 3.34 respectively. The non-clinical distress group reported a mean anxiety and depression score of 2.00 ± 1.72 and 1.75 ± 1.07; while the borderline clinical group reported 9.23 ± 1.54 and 7.38 ± 4.19 respectively. Additional demographic and clinical data are presented in Tables 1 and 2 in case-by-case and quantitative formats respectively. Pertinent narrative data are presented in Tables 3, 4, 5, referenced in text below by italicized numbers, (e.g. Table 3, 1.1).

Table 1 Personal and clinical characteristics of the participants (case-by-case)

Table 2 Personal and clinical characteristics of the participants (quantitative)

Nature of sleep disturbance (Table 3, 1.1–1.3)

Regardless of the psychological distress level, all patients reported similar patterns of sleep disturbance, including nocturnal waking, long sleep onset latency, and shortened sleep duration.

Patients frequently reported greater sleep onset latency compared to before their cancer diagnosis, sometimes waiting 30 min to 4 h after getting in bed before sleep onset (1.1). Frequent nocturnal wakening with difficulty in resuming sleep after waking in the middle of the night (1.2), together with long sleep onset latency effectively reduced the nighttime sleep duration (1.3) were common problems. Some patients reported large reductions in sleep duration after cancer diagnosis compared to before, with a reduction from approximately eight to five hours (1.3).

Table 3 Nature of sleep disturbance and common triggers in cancer survivors, narrative quotes

Common triggers of sleep disturbances (Table 3, 2.1–2.4)

Common triggers of sleep disturbance were identified for both patients with non-clinical or borderline to clinical levels of distress. These included treatment-related side effects, intrusive thoughts of cancer, fears of cancer recurrence, and non-cancer-related factors.

Treatment-related side effects (2.1)

Treatment brought upon a myriad of physical side effects which contributed to sleep disturbances. For example, a breast cancer patient (Case 20) spoke about how treatment-induced menopausal symptoms, hot flushes and sweating, lead to frequent nocturnal wakening. Persistent symptoms of peripheral neuropathy, including numbing and prickling at night, were experienced by a gynecological cancer patient who had completed chemotherapy (Case 1). Apart from the physical side-effects of treatment contributing to sleep disturbance, patients also perceived treatment to have disrupted their sleep–wake cycle, which was most commonly reported by those who had undergone chemotherapy or radiotherapy. For example, a patient with lymphoma (Case 7) experienced a significant deterioration of sleep quality after receiving a combination of chemotherapy and targeted therapy, which persisted beyond treatment completion.

Extended periods of hospitalization as a result of treatment complications negatively impacted sleep patterns for one patient. Even after being discharged, a patient with head and neck cancer (Case 10) faced difficulties in falling asleep at night, and even struggled to fall asleep in the day when attempting to make up for lost sleep.

Intrusive thoughts about cancer and fear of cancer recurrence (2.2)

Irrespective of levels of distress, intrusive thoughts about the cancer treatment process, or fears of cancer recurrence and progression were common. Patients reported nightmares disrupting sleep quality in the form of vivid flashbacks regarding the cancer treatment process (Case 1) which they perceived as traumatic, painful and frightening. Recalling the trauma of treatment also occurred at night when distractions are fewer, causing difficulty in initiating sleep (Case 27). One patient (Case 5) reported having recurring nightmares of deceased relatives during chemotherapy, which continued regularly after treatment completion. These nightmares often triggered thoughts of the severe consequences of cancer recurrence. Anticipatory anxiety affected sleeping as regular check-ups with oncologists approached, triggering fear of recurrence, adding to existing anxiety (Case 16). Fears of recurrence also accompanied other worries concerning the potential burden that recurrence may have on family members on top of adjustment concerns to cancer, such as the implications of their ability to return to work, which often kept their minds active before falling asleep (Case 20).

Poor sleep hygiene (2.3)

Non-cancer-related factors, such as poor sleep hygiene or disruptive sleeping environments had also contributed to poor sleep. For example, a partner's persistent snoring was a source of frustration for the patient as it has consistently prevented them from falling asleep (Case 28). Further, a considerable number of patients admitted to the habit of scrolling their phones in bed. Although the patient was aware of the detrimental effects on their sleep quality, they struggled to break free from the habit, as they used it as a way to manage stress after a busy day of work (Case 23).

Lack of routine (2.4)

Many patients noted a lack of employment as having a noticeable effect on sleep quality. For example, a patient (Case 17) observed that having no plans in the day would result in a shortened sleep duration to which they would wake up too early in the morning. Meanwhile, completing the chores and engaging in housework helped them to sleep better. Another perceived that the physical and mental demands of their jobs before retirement would naturally lead to increased daytime fatigue and ultimately result in better sleep quality at night (Case 13).

Differences in experiences of sleep disturbances in patients between varying distress levels

Table 4 documents sleep disturbance experiences in borderline to clinical distress (Table 4.A) versus non-clinical distress (Table 4.B). Differences and similarities in experiences between both groups are visualized in Fig. 1.

Table 4 Differences in experiences of sleep disturbances in patients between varying distress levels, narrative quotes

Fig. 1

Triggers of sleep disturbances and coping responses of varying distress level

Patients with borderline or clinical psychological distress (Table 4.A)

Patients who had higher levels of psychological distress more often reported rumination about their progress towards recovery, and experienced greater concern about how negative emotions and poor sleep might impact their recovery. Consequently, they felt a heightened pressure to maintain good sleep quality. Patients also reported ongoing life stressors and lack of social support as triggers for sleep disturbances.

Rumination about recovery and returning to normal (4.A.1)

Patients with non-clinical and borderline or clinical psychological distress both experienced cancer-related side effects that negatively affected their sleep, however the latter group was found to fixate on their symptoms as an indication of poor recovery progress and inability to return to normal. A patient (Case 8) exhibited unbearable levels of discomfort from treatment side-effects, which prevented them from falling asleep easily. They perceived symptoms as uncontrollable and managing them to be an isolating experience, as they believed the symptoms would last indefinitely. While patients with non-clinical levels of distress tended to see treatment-related symptoms as a natural part of recovery, patients with higher distress levels seemed to find them overwhelming. One patient mentioned having once preferred death over facing their symptoms, particularly during the treatment period, which contributed to disturbing their sleep (Case 25). A patient (Case 15) was observed to exhibit upward comparison; as they had perceived their symptoms to be more severe when comparing with other patients at regular check-ups, which left them with feelings of uncertainty about their recovery.

Worry about negative emotions affecting cancer progression and subsequent thought suppression (4.A.2)

Patients with higher distress frequently expressed worry about whether having negative emotions arising from ruminating about cancer would further impact their health. For example, rumination of their side effects led to additional worry about how these negative emotions would affect their health condition (meta-worry) (Case 8). While conscious efforts to maintain a positive mindset by suppressing negative thoughts were made, patients also acknowledged that this was often challenging (Case 8). Another patient worried whether feelings of anger, triggered by arguments with their partner, would hinder the effectiveness of chemotherapy treatment. This worry in turn caused additional distress, which led them to avoid situations that lead to anger in order to better control their emotions (emotional suppression) (Case 1).

Worry about poor sleep affecting recovery, and subsequent pressure to achieve good sleep (4.A.3)

Many patients with higher distress exhibited concerns about the potential consequences of poor sleep, alike to the above reported effects of negative emotions on cancer recurrence or progression (Case 7). For example, a patient (Case 24) reported that maintaining good sleep was especially important given their history of cancer recurrence.

However, conscious efforts to fall asleep or by taking naps during the day to compensate for lost sleep was counterproductive and instead resulted in increased difficulty to sleep (Case 23). Anxiety over sleep concerns may also be reinforced by their sleep quality of the previous night, fearing their sleep difficulties would continue as they had already experienced it multiple nights in a row (Case 1). Patients also monitored bodily sensations, such as the level of comfort achieved in their sleeping environment (Case 27) or for any physical symptoms (Case 24), to determine the reasons behind their sleep difficulties.

High sleep reactivity to ongoing life stressors and lack of social support (4.A.4)

Apart from cancer-related factors, patients with higher distress were more likely to exhibit greater rumination towards other sources of stress such as family-related worries, planned engagements for the next day, and work stress, which contributed to increased difficulty in falling asleep (Case 26, 27). Likewise, it was commonly observed by patients that worry of being unable to sleep ultimately resulted in an increased failure to fall asleep (Case 32).

Alongside ongoing life stressors, patients with higher distress often reported having limited social support. For example, arguments that arose from a patient’s dissatisfaction towards the partner’s emotional and financial support towards the patient’s treatment expenses precipitated rumination on these issues before sleep (Case 1). Again, awareness of their negative emotions also became a source of worry for cancer progression. Alternatively, a patient (Case 31) cited the primary cause of her sleep disturbances, aside from cancer, was the burden and stress of being a full-time caregiver for a family member with intellectual disability.

Patients with non-clinical psychological distress (Table 4.B)

Patients who experienced lower levels of psychological distress typically demonstrated acceptance of their illness and treatment process, placed greater emphasis on moving forward with life after cancer, and expressed a shift in personal values to prioritize health. Simultaneously, they placed less fixation on achieving good sleep quality and were more likely to report comorbid health conditions diagnosed prior to cancer as contributors of sleep disturbance.

Acceptance, resilience and optimism towards cancer and treatment experience (4.B.1)

In contrast to those with higher distress, those with non-clinical distress generally attributed less emotional distress to their treatment side-effects. This was seen in Case 11, where an initial fear of potential radiotherapy side-effects evolved to a positive reappraisal of their cancer treatment journey after realizing that radiotherapy-induced damage was less than anticipated. Further, they were more likely to reframe their perspective by reflecting on the adversities they had faced in the past and used them as sources of motivation for increased personal growth to further overcome future difficulties (Case 14).

Change in life values, and commitment to prioritizing one’s health (4.B.2)

In contrast to those with higher distress, patients with less distress demonstrated a shift in values and priorities after cancer treatment, placing greater emphasis on caring for their health rather than fixating on their recovery progress. For example, a patient (Case 16) displayed a stronger focus on the positive aspects of their cancer treatment experience and demonstrated a commitment to actively seek ways to improve their health. They also expressed that it no longer feels worth it to exert themselves. Instead, they accepted their physical limitations after cancer, made necessary adjustments to their behavior accordingly, and embraced their new normal. Similarly, while one patient (Case 14) shared their perspective on the inevitability of death, they also indicated their commitment to making most of the present moment.

Self-distraction of cancer-related worries to cope with sleep disturbances (4.B.3)

While those with high distress engaged in avoidant strategies, such as disengaging from negative thoughts, those with non-clinical levels of distress conversely engaged in distraction of negative thoughts, by actively engaging in activities, such as mindfulness, or listening to the radio, that redeployed attention to external activities (Case 20; Case 30).

Fewer expectations towards sleep quality (4.B.4)

Compared with those with high distress, patients with non-clinical distress exhibited fewer expectations regarding their sleep quality. Instead, patients tended to accept sleep difficulties if they arose (Case 2). Some patients were not very worried about how much time they slept and whether it would affect their daily functioning (Case 20).

Pre-existing comorbid health conditions lead to sleep disturbance (4.B.5)

Many patients with non-clinical distress had pre-existing conditions that sometimes interfered with sleep, so were more accepting (Case 4). Cancer treatment was perceived by some to have worsened the symptoms of their comorbid conditions (e.g. herniated disc), further exacerbating their pre-existing sleep disturbance (Case 2). Consequently, many reported having become accustomed to sleeping poorly for many years (Case 3), suggesting that their sleep issues were unrelated to cancer.

Common help-seeking behaviors in managing sleep disturbances (Table 5)

Irrespective of distress levels, both groups reported reluctance or opposition to seeking help from oncologists towards sleep disturbances. Patients either underestimated the severity of their sleep problems, believed it to have little effect on their daily lives or prioritized the treatment of other symptoms over sleep disturbance.

Table 5 Common help-seeking behaviors in managing sleep disturbances, narrative quotes

Lack of urgency to address sleep disturbances with oncologist (5.1)

Patients with pre-existing sleep disturbance accepted poor sleep as a normal part of their lives (Case 2). They reported that they did not feel that sleep disturbance had a significant impact on their daily functioning, reflecting a lack of urgency in addressing sleep disturbances (Case 32). Some patients perceived other symptoms to be more important to address, such as unexplained pain in their hands and feet (Case 9).

Preference for using Chinese medicine over Western sleep medication (5.2)

Patients universally had negative opinions of sleep medication and Western medication in general, expressing concerns about its potential damaging effects on health and dependence. In contrast, there was widespread consensus in favor of seeking Chinese medicine as a method to treat sleep disturbances and other cancer-related symptoms (Case 4, Case 33)., they believed that traditional Chinese medicine (TCM) unlike allopathic medicine not only improves sleep quality, but also promotes overall health after undergoing cytotoxic cancer treatment, without having negative effects on the body (Case 10).

Perceived lack of support from oncologists for sleep and other health-related matters (5.3)

Reluctance to seek support was often influenced by previous experiences during regular check-ups with oncologists. For example, patients were informed that poor sleep was a normal post-treatment experience; and that there were few options available to manage sleep disturbances (Case 7). Some indicated disappointment or frustration with the oncologists’ responses, as they either felt that their concerns and worries were dismissed (Case 28), or that the oncologists had not provided enough information or guidance on symptom management post-treatment (Case 25). This often led to a sense of helplessness and uncertainty after their appointments.

Discussion

This qualitative study compared the experiences and perceptions of sleep disturbances in cancer survivors between those without and with psychological distress. The findings revealed that irrespective of the presence of psychological distress, cancer survivors who have completed treatment continue to face persistent physical and psychological challenges, which contribute to sleep disturbances. Consistent with previous research, common triggers of sleep disturbances included treatment-related side effects [30, 48, 49], intrusive thoughts about cancer [50, 51], and fear of cancer recurrence or progression [52]. Non-cancer-related triggers of sleep disturbance were also identified, including a lack of routine, inactivity and poor sleep hygiene. As the majority of participants were unemployed, patients may have lower physical and cognitive engagement, which can lead to poorer sleep and irregular sleep–wake cycles [53] and disrupted sleep habits [29]. Notably, a number of patients had reported having long-standing sleeping difficulties that pre-dated their cancer diagnosis.

This qualitative study identified several notable differences between patients with various distress levels in how they adopted different coping responses towards common triggers of sleep disturbances, as well as differences in perceptions of sleep disturbances, which compounded existing sleep difficulties. Patients with borderline or clinical psychological distress more often mentioned rumination and worry about recovery after cancer, particularly regarding treatment side-effects, which often contributed to difficulty in falling asleep. High levels of worry regarding both negative emotions and poor sleep impairing cancer progression were often mentioned. This sleep-related worry prompted anxiety around feared negative consequences of sleep loss, such as cancer recurrence. Coping methods, including thought and emotional suppression, increased pressure to sleep, and heightened monitoring of sleep cues (e.g., bodily sensations for signs consistent with falling asleep) which are highly counterproductive, perpetuated sleep disturbances instead. Anticipation of sleep difficulties increases arousal around sleep which in turn delays sleep onset and confirms that the anticipation was justified. This then becomes self-sustaining. These findings align with Harvey’s cognitive model of insomnia [28], which proposes that the combination of sleep-related worry, selective attention and monitoring, and maladaptive safety behaviors (attempts to avoid or control unwanted thoughts) throughout the day contributes to increased arousal and interferes with sleep at night. However, worry about negative emotions arising when ruminating on cancer related side effects (meta-worry) or poor sleep potentially contributing to cancer progression or recurrence is also consistent with the newer metacognitive model of insomnia [54]. This model proposes that attentional bias towards sleep-related cues that interfere with sleep (primary arousal) may amplify the existing negative emotional valence (secondary arousal) associated with these thoughts, further exacerbating the inability to fall asleep. Such negative emotions feedback to further increase worry and intensify attentional bias. In the context of cancer, patients with high distress may be more vulnerable to sleep disturbances than the general population, as selective attention towards sleep-related worries or physical symptoms (e.g. pain) may amplify personally relevant fears, including cancer recurrence, progression and ability to return to normalcy.

Patients with borderline or clinical distress also mentioned nocturnal rumination about ongoing life stressors unrelated to cancer. These observations resemble trait sleep reactivity, which refers to an increased likelihood of developing insomnia in response to stressful events [55]. Trait sleep reactivity was not only found to moderate the effects of stress-induced intrusive thoughts on insomnia, but insomnia had also mediated the effect of trait sleep reactivity on depression [56]. Hence, it can be inferred that high levels of sleep reactivity may further exacerbate sleep disturbances by amplifying the impact of stress-induced or cancer-related intrusive thoughts in patients with higher distress levels; which in turn may also exacerbate existing depressive symptoms. Additionally, social support for this group was limited, which may further contribute to a sense of isolation, reduced emotional well-being and increased use of maladaptive coping strategies to manage sleep disturbances [57].

In contrast, patients with non-clinical distress exhibited noticeably less emotional distress in response to treatment-related physical symptoms. Their adoption of better adaptive mechanisms to manage the impact of cancer included a changed commitment to prioritizing one’s health, acceptance of their cancer treatment experience, while focusing on self-improvement rather than just recovery progress. This is concurrent with previous research that has shown that coping skills such as resilience, self-efficacy and emotion regulation may protect against psychological distress [58, 59] after treatment completion in cancer survivors. Observed capacities to adapt their actions to personal goals and values while accepting the reality of their adversities closely mirrors psychological flexibility, a core construct of the Acceptance and Commitment Therapy Model (ACT) [60]. This aligns with previous research that employed latent profile analysis which demonstrated that those in the low psychological flexibility class reported the highest levels of psychological distress, whereas those in the high psychological flexibility class reported the lowest levels of psychological distress [61]. Based on the ACT model, it can be inferred that patients with non-clinical distress have higher psychological flexibility; thus, they are able to experience and observe unpleasant, negative physical and psychological concerns about cancer and their inability to sleep, without having the urge to control them [62].

Additionally, while the borderline to clinical distress group engaged in thought suppression, the non-clinical distress group engaged in self-distraction and external attentional focus to cope with sleep disturbances. While it can be argued that both groups engaged in avoidant coping, some research has suggested that self-distraction is a predictor of better sleep quality [63], as diversion of attention is achieved by replacing an unwanted thought with another, which is thought to be a temporary reprieve to prevent the individual from re-engaging in worries and concerns [28]. This coping mechanism potentially enabled them to effectively reduce the impact of cancer-related worries on sleep disturbances. Differences in perceptions of sleep were also observed; patients with non-clinical distress had less concern over their sleep disturbances and had lower expectations of sleep quality. This may be accounted for by physical symptoms associated with pre-existing comorbid health conditions that had already contributed to sleep disturbances before cancer diagnosis, which were more commonly observed in the group with non-clinical distress. This is consistent with previous longitudinal research indicating that higher comorbidity is an explanatory variable for sleep disturbances in lung cancer patients [64]. As a result, although cancer-related factors may still trigger sleep disturbances for this group, the associated metacognitions surrounding cancer-related concerns and sleep-related worry may be less likely to be a contributor of poor sleep.

This qualitative study also captured help-seeking behaviors in response to sleep disturbances. Most patients, regardless of psychological distress levels, were reluctant to seek help from oncologists. This reluctance was influenced by an unfavorable view sleep medication specifically and Western medication in general, coupled with past negative experiences with oncologists when addressing their health-related concerns. This sample of Chinese patients preferred to use traditional Chinese medicine (TCM) to reduce side effects, aid recovery and enhance immunity after treatment; and deemed Western medication to be “toxic”. However, recent evidence has raised concerns regarding the safety of drug-herb interactions, particularly when combined with cancer treatment [65]. Additionally, reported negative interactions with medical staff are consistent with the service gaps identified in the overall survivorship care in Hong Kong, particularly in regards to unmet healthcare information needs [66, 67], which may be likely to be driven by low satisfaction or poor patient education [68]. Sleep disturbances are often presumed by both clinicians and cancer patients to be a transient response to cancer diagnosis and treatment, which ultimately self-resolves. Consequently, patients rarely discuss sleep disturbances with their oncology team [36]. Routine screening for sleep disturbances and more information regarding the benefits and limitations of different treatment options at oncology clinics should be provided to help patients make informed treatment decisions.

The findings have provided insights into the suitability of future interventions for patients with sleep disturbances. As sleep disturbances and psychological distress may not always present as a cluster, particularly during long-term survivorship, interventions that target only one area are likely to fail. A stepped-care program targeting patients with different distress levels may potentially offer a tailored approach to manage sleep disturbances. Cancer survivors, including those with low distress levels may benefit from physical activity programs that help to establish structure and increase activity in their daily routine [69], symptom management interventions to reduce discomfort-related causes of sleep disturbances [70], and encouragement to adopt greater externalizing focus and engagement in cognitively-taxing activities. Meanwhile, those with high distress are likely to benefit from interventions that target maladaptive emotion-focused coping strategies, such as sleep-related worry and metacognitions of worry, particularly those who are socially isolated. These may include acceptance and commitment therapy [54, 71], or cognitive behavioral therapy for insomnia [72], which has been recently found to produce similar effects on reducing depression compared with cognitive behavioral therapy for depression [73].

Our study has some methodological limitations. Sleep disturbance was only assessed once at recruitment, which may have unintentionally captured patients who had acute sleep disturbances affected by ongoing life stress. Future studies may implement repeated measurements over three months or longer in order to recruit patients with persistent sleep disturbances or chronic insomnia [74]. Furthermore, there was an unequal representation of patients with borderline to clinical or non-clinical levels of distress, which may affect the generalizability of the findings. However, the proportion of borderline to clinical levels of distress identified in the current study (39.4%) was similar to previous prevalence reports of head and neck cancer patients which constituted the majority of our sample. 21.1% and 48.9% of head and neck cancer patients with persistent poor sleep (PSQI > 5) were previously reported to have depression or anxiety (HADS > 7), respectively [75]. Thus, the unequal representation of patient groups in this study may be attributed to the overall lower prevalence of patients with depression or anxiety. Lastly, while the qualitative study captured various sleep disturbance experiences across different cancer types, majority of the sample consisted of breast, head and neck and gynecological cancers. Consequently, the unique experiences of sleep disturbances and treatment-related factors of other cancer types may not be adequately represented as clinical characteristics were not adjusted for. Future qualitative research may consider focusing on specific cancer types, cancer stages or treatment types to better understand how distress may uniquely impact sleep disturbances in different contexts.

In summary, while treatment-related side effects, intrusive thoughts about cancer, recurrence concerns and poor sleep hygiene may trigger sleep disturbances, patients with higher distress may be particularly vulnerable to maladaptive coping responses, such as increased worry around recovery after cancer, sleep-related worry, meta-worry, thought suppression, and high sleep reactivity, which may further perpetuate sleep disturbances. In contrast, those with non-clinical distress were more likely to experience persistent sleep disturbance as a result of coexisting physical symptoms related to other comorbid health conditions. Coupled with their reluctance in seeking professional help for supportive care services after cancer treatment, patients may not be driven to manage ongoing sleep disturbances. Future longitudinal studies may consider testing the effect of potential risk factors identified in contributing to sleep disturbances, as well as mediating pathways that operate across different distress levels. Pilot intervention studies are warranted in order to compare the effectiveness of customized approaches to manage sleep disturbances based on distress levels.