Summary of thesis
Lung cancer is the leading cause of death by cancer worldwide, accounting for approximately 20% of cancer deaths. Besides a poor prognosis, lung cancer patients suffer from severe physical symptoms and undergo intensive treatment. Also partners are emotionally affected by lung cancer as they often take on the role of caregiver and face the fear of losing their partner. The burden lung cancer poses on patients and their partners makes them vulnerable to developing psychological distress and psychiatric disorders. Lung cancer patients report among the highest psychological distress rates of all cancer patients. Despite these high distress rates, lung cancer patients are less likely to receive psychosocial care than patients with other cancer types. Moreover, limited research has been conducted on the effectiveness of psychosocial interventions in lung cancer patients and their partners. Recently, mindfulness-based interventions (MBIs), such as MBSR, have proven to be effective in reducing psychological distress in cancer patients. However, hardly any evidence is available on the effectiveness of MBSR in lung cancer patients and their partners.
1. How suitable are commonly used self-report questionnaires to differentiate between lung cancer patients and partners with and without a psychiatric disorder?
In a systematic screening study (Chapter 2), we examined to what extent the Hospital Anxiety and Depression Scale (HADS), Distress Thermometer, Beck Depression Inventory and State subscale of State Trait Anxiety Inventory were suitable to screen for psychiatric disorders in lung cancer patients and partners. A consecutive sample of 144 patients and 99 partners completed the screening instruments and were interviewed with the Structured Clinical Interview DSM-IV (SCID-I) to diagnose psychiatric axis I disorders. Overall, 18% of patients and 20% of partners were diagnosed with a psychiatric disorder (i.e. anxiety disorders, depressive disorders and adjustment disorder). In patients and partners, the HADS total score outperformed the other questionnaires in terms of both ruling out those without a psychiatric disorder and identifying those with a psychiatric disorder, using a cut-off level of ≥15. 8 153 The findings of this screening study implied that the HADS seems the most suitable screening measure to differentiate between those with and without a psychiatric disorder. Patients and partners scoring above the cut-off should be referred to a psychologist or psychiatrist for further diagnostics and treatment.
2. What is the currently available evidence for the effectiveness of MBIs in reducing psychological distress in cancer patients?
A systematic review (Chapter 3) was conducted on randomized controlled trials (RCT) that examined the effectiveness of MBIs in cancer patients and have been published since an earlier meta-analysis in 2012. We included 5 RCTs (n = 690), which confirmed the effectiveness of MBIs in decreasing psychological distress and improving quality of life. The methodological quality of the studies was good. Three RCTs reported on a comparison with an active control group, demonstrating that the MBI was superior to Supportive Expressive Group Therapy (SET) and a nutrition education programme in reducing distress, but inferior to Cognitive Behavioural Therapy in reducing insomnia. The external validity of the RCTs was low once again. The majority of participants were women and diagnosed with curable breast cancer. Fortunately, ongoing trials are examining other cancer populations, such as lung and prostate cancer, in palliative stages as well.
Interestingly, since the publication of this systematic review in 2015, four new RCTs have been published, of which three demonstrated the effectiveness of MBIs on a range of outcomes in breast cancer patients, such as pain, fatigue and post-traumatic growth (Johannsen et al. 2016; Lengacher et al. 2016; Zhang, Zhou et al. 2016). Importantly, the RCT in advanced prostate cancer patients has also been published (Chambers et al. 2016), revealing that the men did not benefit from the six 45-min MBCT sessions delivered by telephone in comparison to minimally enhanced usual care.
3. What is the effectiveness of MBSR added to CAU compared to solely CAU in reducing psychological distress in lung cancer patients and their partners?
In the MILON study, a multicentre, parallel-group RCT (Chapter 4), patients with lung cancer and their partners were randomised to either MBSR in addition to care as usual (CAU+MBSR) or solely CAU. MBSR is an 8-week group-based intervention, including mindfulness practices and teachings on stress. CAU included anti-cancer treatment, medical consultations and supportive care. The primary outcome was psychological distress (HADS). Secondary outcomes included quality of life, caregiver Chapter 8. Summary and General Discussion 154 burden, relationship satisfaction, mindfulness skills, self-compassion, rumination and post-traumatic stress symptoms. Outcomes were assessed at baseline, post-intervention and at 3-month follow-up. Linear mixed modeling was conducted on an intention-totreat and per-protocol sample. Results of the MILON study (Chapter 5) demonstrated that 63 patients and 44 partners were included in the trial; 31 patients and 21 partners were randomized to MBSR and 32 patients and 23 partners to CAU. As hypothesized, patients in the CAU+MBSR group reported significantly less psychological distress than those in the CAU group. Additionally, patients showed more improvements in quality of life, mindfulness skills, self-compassion and rumination after CAU+MBSR versus CAU. Baseline distress levels appeared to predict treatment outcome: those with more distress benefitted most from MBSR. In partners, no differences were found between the two groups. To conclude, this RCT suggested that MBSR can reduce psychological distress and improve quality of life in patients, especially in distressed patients. However, partners did not seem to benefit from MBSR, possibly because they were more focused on patients’ wellbeing rather than their own.
4. How do lung cancer patients and their partners who refuse participation in a trial on MBSR differ from those who do participate?
And what are the reasons of patients and partners to refuse or to participate? In a mixed methods study (Chapter 6) we examined the characteristics of lung cancer patients and partners who participated and refused participation in the RCT on MBSR, and their underlying reasons for refusing or participating. After participation in the screening study (Chapter 2), a subsample of 137 lung cancer patients and 99 partners were invited for the RCT, of which 21 patients and 13 partners eventually participated. Patients who were retired, who received no current anti-cancer treatment and who reported higher levels of self-compassion were more likely to refuse than to participate. Partners who reported lower psychological distress levels were more likely to refuse participation. Qualitative analysis showed that participants wanted to participate because they or their partner were distressed and in need of help. Some refusers, however, reported distress but did not want help because they did not want to face the fact they (or their partner) had lung cancer. By integrating psychosocial interventions into regular cancer care, we might be able to better reach those patients and partners in need of psychosocial care.
5. What kind of role do mindfulness and self-compassion play in the relationship between patients and partners with respect to psychological distress and communication about cancer?
More specifically, to what extent are mindfulness and self-compassion of oneself and mindfulness and self-compassion of one’s partner related to one’s psychological distress and communication about cancer? In a cross-sectional sample (Chapter 7) of 88 couples facing lung cancer, the actorpartner interdependence model was used to examine how mindfulness and selfcompassion are related to psychological distress and communication about cancer within and between partners. Within partners, levels of mindfulness and self-compassion were inversely related to levels of psychological distress. At a dyadic level we found that the association between self-compassion and distress in one partner was less strong if the other partner reported higher levels of self-compassion. In addition, within partners levels of self-compassion were positively associated with communication about cancer, while levels of mindfulness were not. At a dyadic level, mindfulness of one partner tended to be related to more open communication in the other partner. These findings point to the possibility that mindfulness and self-compassion skills go beyond the individual, and may impact couple functioning.
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Schellekens, M., van den Hurk, D., Prins, J., Molema, J., van der Drift, M., & Speckens, A. (2016). The suitability of the Hospital Anxiety and Depression Scale, Distress Thermometer and other instruments to screen for psychiatric disorders in both lung cancer patients and their partners.
Schellekens, M., Compen, F., van der Lee, M., van der Drift, M., & Speckens, A. (2015). The effectiveness of mindfulness-based interventions for patients with cancer: A systematic review of recent randomised trials.
Schellekens, M., van den Hurk, D., Prins, J., Molema, J., Donders, R., Woertman, W., van der Drift, M., & Speckens, A. (2014). Study protocol of a randomized controlled trial comparing mindfulness-based stress reduction with treatment as usual in reducing psychological distress in patients with lung cancer and their partners: the MILON study.
Schellekens, M., van den Hurk, D., Donders, A., Molema, J., Dekhuijzen, R., van der Drift, M., & Speckens, A. (2017). Mindfulness-based stress reduction added to care as usual for lung cancer patients and/or their partners: A multicentre randomized controlled trial
Schellekens, M., Karremans, J., van der Drift, M., Molema, J., van den Hurk, D., Prins, J., & Speckens, A. (2017). Are Mindfulness and Self-compassion related to psychological distress and communication in couples facing lung cancer? A dyadic approach.