Introduction
Cancer is becoming a long-term health condition, with approximately 70% of patients living for at least 5 years from the time of diagnosis (Cancer Research UK). Psychological distress commonly occurs in cancer survivors. A systematic review on the prevalence of anxiety and depression in cancer survivors at least 2 years post-diagnosis reported prevalence of 11.6% for depression and 17.9% for anxiety (Mitchell et al.
2013). An earlier review concluded that approximately 25% of adult cancer survivors experience levels of anxiety and depression warranting treatment (Hoffman et al.
2009). Fear of cancer recurrence (FCR), defined as worry about cancer returning or advancing in the same or a different body part (Vickberg
2003), is also very common in cancer survivors. Across tumour groups, approximately 56% of survivors experience moderate to high FCR (Simard et al.
2013). Psychiatric comorbidity is common in cancer survivors; anxiety and depression often co-occur (Mehnert and Koch
2008) and, in survivors with clinical levels of FCR, psychiatric comorbidity is the rule rather than exception (Simard and Savard
2015). Anxiety, depression and FCR are all linked to poorer quality of life (Lebel et al.
2013) and increased healthcare use and costs (Sarkar et al.
2015).
The development of psychological interventions for cancer patients has tended to follow the disorder-specific approach used in mental health. Disorder-specific approaches focus on one clinical problem at a time; therefore, distinct protocols exist for treating anxiety and depression in cancer patients and survivors (e.g. Greer et al.
2010; Hopko et al.
2007). More recently, protocols have been developed to address FCR also (e.g. Butow et al.
2013; Maheu et al.
2016). However, a disorder-specific approach to psychological morbidity in cancer survivors may not be the most cost-effective or efficacious approach Disorder-specific approaches require interventions to be tailored to the main presenting complaint, which could limit their clinical utility because of the comorbidity of anxiety, depression and FCR in cancer survivors. Disorder-specific approaches may also limit the dissemination of psychological treatments as they require healthcare professionals to be trained in different therapeutic models and associated interventions (Norton and Paulus
2016). A transdiagnostic approach offers a more cost-effective model of training, requiring practitioners to develop competency in a single treatment protocol applicable to patients regardless of their specific symptoms of distress (McEvoy et al.
2009). Furthermore, transdiagnostic approaches may offer patients a more time-efficient intervention because comorbid problems could be treated concurrently, rather than sequentially by disorder specific interventions. Basing intervention on a transdiagnostic model of psychopathology which can account for all forms of psychological distress would be a significant advance in treating cancer survivors.
Metacognitive therapy is based on the transdiagnostic model of metacognitive processes in psychopathology, the Self-regulatory executive function (S-REF) model (Wells and Matthews
1994). The S-REF model states that all forms of emotional disorder are maintained by the cognitive-attentional syndrome (CAS), which comprises three processes: (i) perseverative thinking (e.g. worry, rumination, over-analysing); (ii) inflexible self-focused attention (monitoring for signs of threat); and (iii) counterproductive coping strategies that impair cognitive and emotional regulation. Cancer survivors experience many types of negative thoughts (e.g. thoughts about cancer returning, memories or images of their cancer treatment, thoughts of loss), which can result in further conceptual processing, such as worrying about coping with cancer recurrence or ruminating about implications of cancer on work and family roles. For most patients, worry and rumination are transient but, in those who will become depressed or anxious, they persist.
The S-REF model specifies that the CAS is activated and guided by positive and negative metacognitive beliefs. Positive metacognitive beliefs concern the usefulness of worry, ruminating, threat monitoring and coping strategies e.g. “worrying will help me cope”, “monitoring my symptoms constantly keeps me safe”. Unfortunately, worry/rumination and each aspect of the CAS are counter-productive, because they increase negative thoughts and broaden the sense of threat. The individual responds as if the negative thought is valid and important, preventing the development of a more flexible relationship with negative thoughts that can reduce worry/rumination. Similarly, the S-REF model explains how threat monitoring (e.g. scanning for symptoms or for negative thoughts) and maladaptive coping behaviours (e.g. avoiding reminders of cancer, withdrawal, distraction) are driven by metacognitive beliefs that these strategies will be helpful. However, the coping strategies have the opposite effect by maintaining the sense of threat and personal vulnerability so that emotional distress persists or escalates. Within the S-REF model, negative metacognitive beliefs are of fundamental importance to persistent emotional distress. There are two main domains of negative metacognitive beliefs: that perseverative thinking is uncontrollable (e.g. “I cannot control my worry”, “I can’t stop analysing my past mistakes”) and that it can be harmful mentally and/or physically (e.g. “I could lose control of my mind”). Activation of these negative metacognitive beliefs leads to worry about worry, which in turn increases distress. Furthermore, negative metacognitive beliefs concerning the uncontrollability of perseverative thinking result in limited effort to stop worry/rumination as the individual believes it is not possible to do so, thereby further maintaining distress.
Considerable evidence supports the association between metacognitive beliefs and emotional distress in a range of anxiety and depressive disorders in mental health (e.g. Wells
2013), with emerging evidence in several physical health populations including chronic fatigue (Maher-Edwards et al.
2011), epilepsy (Fisher et al.
2016), and Parkinson’s disease (Brown and Fernie
2015). Recent studies suggest that metacognitive theory and therapy can be translated to cancer patients and survivors specifically. In patients with recently diagnosed breast or prostate cancer, metacognitive beliefs were associated with anxiety, depression and trauma symptoms after controlling for negative health beliefs (Cook et al.
2015a). In a prospective study, breast and prostate cancer patients’ metacognitive beliefs around the time of diagnosis predicted anxiety, depression and trauma symptoms 12 months later, after controlling for baseline symptoms and metacognitive beliefs (Cook et al.
2015b). Metacognitive beliefs are also significantly higher in breast cancer patients with clinical levels of FCR compared to those patients without FCR (Butow et al.
2015).
Key components of the CAS have also been linked to heightened emotional distress in cancer survivors. Worry about general health and cancer is associated with elevated anxiety and depression (Deimling et al.
2006). The association between worry about cancer recurrence or progression and distress has been extensively documented (Simard et al.
2013). In cancer survivors, rumination in response to negative thoughts is associated with greater distress (Morris and Shakespeare-Finch
2011) and mediates the relationship between harm/loss cognitions and depression (Steiner et al.
2014). There is also emerging evidence that anxious cancer patients show an attentional bias for threat-related stimuli (e.g. Chan et al.
2011; Butow et al.
2015) which is consistent with the role of maladaptive attentional processing in the S-REF model.
There has been one treatment study of MCT in cancer patients: an open trial in young adult survivors of paediatric cancer (Fisher et al.
2015). MCT reduced anxiety, trauma symptoms and depression, with treatment gains maintained through to 6-months follow-up. In that study, MCT was delivered according to a transdiagnostic model (Wells
2009) over an average of nine 1-h sessions the intervention is described in a case study (McNicol et al.
2013). Reducing the costs of psychological interventions in cancer care by providing brief interventions is important given the limited resources of public healthcare systems (Jansen et al.
2016). MCT has been successfully delivered over only 6–8 sessions for depression (Wells et al.
2012) post-traumatic stress disorder (Wells et al.
2015) and health anxiety (Bailey and Wells
2014), but such brief forms of MCT have not yet been tested in a cancer population. Therefore, the aim of this case series is to evaluate whether MCT delivered in six 1-h session
s could potentially reduce emotional distress, FCR and metacognitive beliefs and processes in adult cancer survivors.
Discussion
This study provides initial evidence that MCT delivered over only six sessions can reduce emotional distress in adult survivors of cancer. MCT was associated with large and clinically meaningful improvements in distress, worry and rumination and fear of cancer recurrence. The treatment gains were broadly maintained to 6-months follow, except for the patient who received an incurable diagnosis shortly before that assessment. MCT appeared acceptable and feasible; all patients completed six sessions. Our findings therefore suggest that brief MCT could be an effective intervention to treat psychological morbidity in cancer survivors. Given its transdiagnostic nature, this stands in contrast to the currently influential view that disorder-specific approaches are needed. Although larger studies using a randomized, controlled design are necessary to replicate our findings, and future studies are needed to compare our intervention to other treatments tested to date, It is possible that the S-REF model provides an alternative model on which to base intervention in this population, and may not need to be combined with additional models such as the common-sense model (Leventhal et al.
1992) and relational frame theory (Barnes-Holmes et al.
2001) as proposed in a recent formulation (Fardell et al.
2016).
The case series has limitations. Two participants did not begin treatment at the end of their randomly allocated pre-defined baseline lengths. Instead, one continued her baseline for 2 extra weeks and the other for 1 extra week. This weakened the non-concurrent multiple baseline design as only two different lengths of baseline were used. However, stability was observed over both the 5 and 6-week baseline periods, and outcome measures improved only after treatment began. There was no independent blind assessment of treatment outcome, and all outcomes were assessed by self-report questionnaires which may have led to overestimation of treatment effects. As with all small-N designs, it is not possible to comment on the generalizability of treatment effects to the broader population of cancer survivors. There was no independent rating of adherence to the treatment manual, although treatment adherence was monitored through weekly supervision sessions. In the present study, the outcomes assessed were limited to overall levels of emotional distress, with secondary analyses of anxiety depression and fear of cancer recurrence. Future studies of brief MCT would benefit from assessing a broader array of outcomes including trauma-related symptoms and quality of life.
Overall, the outcomes in this case series suggest that brief MCT has the potential to be a clinically and cost-effective transdiagnostic intervention for adult cancer survivors. In line with the suggested developmental pathway for translating complex interventions proposed by the MRC (2008), the next step is to conduct studies of brief MCT that use larger samples and randomized designs. This would determine whether the approach is efficacious and whether it confers health-economic advantages relative to comparison interventions.