Abstract
Various psychotherapeutic approaches have been developed to address the psychosocial stressors and distress associated with cancer diagnosis and treatment. One such approach, Acceptance and Commitment Therapy (ACT), may be particularly well suited to people with cancer as it offers a model of healthy adaptation to difficult circumstances. This paper provides a description and theoretical rationale for using ACT in psychosocial oncology care that emphasizes emotional distress and cancer-related pain and provides a narrative review of the current state of evidence for this setting. Six studies met eligibility criteria for inclusion in the review. The research designs included one case study, three pre-post cohort studies, and two randomized controlled trials. Cancer diagnoses of patients included breast cancer, ovarian cancer, colorectal cancer, and mixed cancer populations at various stages of disease progression or recovery. ACT interventions demonstrated significant improvements in symptoms including quality of life and psychological flexibility as well as reductions in symptoms including distress, emotional disturbances, physical pain, and traumatic responses. Overall, although there is limited published research currently available, there is some evidence to support ACT as an effective psychotherapeutic approach for cancer patients. Further research is needed for different cancer populations across the illness trajectory. Barriers to implementation are discussed.
Keywords
Introduction
Cancer is one of the leading causes of death worldwide (Fitzmaurice et al., 2015). In 2012, it was estimated that 14.1 million new cancer cases were diagnosed, 8.2 million cancer-related deaths occurred, and 32.6 million cancer survivors were living within five years of diagnosis (GLOBOCAN, 2012; Torre et al., 2015). Cancer diagnosis and treatment is associated with increased psychosocial stressors and distress. A recent meta-analysis of 70 studies from 14 countries showed that 16.3 and 10.3% of cancer patients (N = 10,071) in oncological and hematological settings met criteria for clinical depression and anxiety, respectively (Mitchell et al., 2011). High levels of reported psychosocial stress led Bultz and Carlson (2005) to recommend that distress be considered the “sixth vital sign” in cancer care, a practice now endorsed by multiple organizations and researchers (Bultz et al., 2011; Holland & Bultz, 2007; Salmon, Clark, McGrath, & Fisher, 2015). Distress not only decreases quality of life but it is also associated with lower immune functioning (Reiche, Nunes, & Morimoto, 2004) and higher mortality rates (Watson, Haviland, Greer, Davidson, & Bliss, 1999). Many people continue to struggle during and following cancer treatments: 20–30% of patients continued to report physical symptoms, psychological distress, interpersonal strain, sexual difficulties, and financial problems more than five years after their cancer diagnosis (Foster, Wright, Hill, Hopkinson, & Roffe, 2009). Notably, between 35 and 96% of cancer patients report that they experience pain (Solano, Gomes, & Higginson, 2006), making it one of the most commonly reported symptoms of diagnosis and treatment and a significant contributor to reduced quality of life.
Psychotherapy can help alleviate distress in cancer patients, including reducing symptoms of depression and anxiety as well as improving quality of life (Faller et al., 2013). However, the reported efficacy of treatment is variable and often considered to be modest (Newell, Sanson-Fisher, & Savolainen, 2002), leaving room for innovations in clinical care to boost the effectiveness of psychosocial oncology interventions. In this narrative review, we describe the theoretical rationale for a relatively new psychotherapeutic approach, Acceptance and Commitment Therapy (ACT), in psychosocial oncology care that may be particularly useful for targeting cancer-related pain and distress. We then compare ACT with other leading approaches, describe the current evidence for ACT with cancer patients, and make recommendations for future research, including a discussion of barriers to implementation.
Theoretical rationale for the use of ACT in psychosocial oncology care
Overview of ACT
Acceptance and Commitment Therapy (ACT) is part of the family of mindfulness- and acceptance-based treatments that have grown in popularity over the past 30 years. Since the publication of the first book articulating the ACT model in 1999 (Hayes, Strosahl, & Wilson, 1999), more than 100 ACT randomized controlled trials have been conducted (Hayes, 2016). These randomized controlled trials show that ACT is effective for a broad variety of mental health concerns, including anxiety and depression (Arch et al., 2012; Forman, Herbert, Moitra, Yeomans, & Geller, 2007), substance abuse (Luoma, Kohlenberg, Hayes, & Fletcher, 2012), psychosis (Bach & Hayes, 2002), aggression (Zarling, Lawrence, & Marchman, 2015), and treatment-resistant psychopathology (Clarke, Kingston, James, Bolderston, & Remington, 2014). ACT has also become popular in behavioral medicine for a variety of chronic illnesses and conditions, such as diabetes (Gregg, Callaghan, Hayes, & Glenn-Lawson, 2007) and chronic pain (Hann & McCracken, 2014; Veehof, Oskam, Schreurs, & Bohlmeijer, 2011). ACT can reduce distress and improve functioning among people living with chronic medical conditions (Dindo, Recober, Marchman, Turvey, & O'Hara, 2012; Hann & McCracken, 2014), as well as encourage changes in health behaviors such as smoking cessation and diet change (Bricker et al., 2014; Bricker, Wyszynski, Comstock, & Heffner, 2013; Gregg et al., 2007). The strength of evidence for the efficacy of ACT in the treatment of chronic pain has led to its endorsement as having “strong research support” by the Society of Clinical Psychology (Division 12) of the American Psychological Association (2016). Furthermore, there is evidence that ACT can reduce distress in caregivers and support staff (Losada et al., 2015; McConachie, McKenzie, Morris, & Walley, 2014), with additional research underway on ACT for caregivers of cancer patients (Köhle et al., 2015).
In recent years, there has been tremendous progress in the medical treatment of cancer; nonetheless, the lived experience of a wide range of cancers involves some degree of unavoidable physical and psychological suffering. While elevated distress is conventionally viewed as abnormal or pathological, ACT is distinctive in its rejection of the “assumption of healthy normality” (Hayes, Strosahl, & Wilson, 2011, p. 5). One of the foundational principles of ACT is that suffering is an inevitable facet of human experience and that it can be managed by responding to difficult life events with “psychological flexibility,” defined as “contacting the present moment as a conscious human being, fully and without needless defense—as it is and not as what it says it is—and persisting with or changing a behavior in the service of chosen values” (Hayes, Strosahl, et al., 2011, pp. 96–97).
Psychological flexibility
The ACT model articulates three fundamental pillars of psychological flexibility that contribute to healthy adjustment when faced with challenges such as cancer diagnosis, treatment, survivorship, or advanced disease: (1) being present, (2) opening up, and (3) doing what matters (Harris, 2009; Hayes, Villatte, Levin, & Hildebrandt, 2011).
Being present
Being present, a fundamental aspect of all mindfulness-based interventions, means bringing awareness to the here-and-now and to present moment experiences, whether they are private (thoughts, feelings, and bodily sensations such as pain, fatigue, and nausea) or public (five senses experience such as what can be seen, heard, and touched, such as watching tree branches sway in the wind, hearing the purr of a well-loved cat, or feeling the soothing touch of a partner). While the content of private and public experiences can shift and change as time passes, experiential exercises presented in ACT cultivate awareness of the continuity of the “observing self,” the part of the self that is able to notice that it is noticing. This cultivation of a sense of self that is steady and constant over time, even in the face of changing circumstances, is readily applicable to people undergoing the major changes in work, relationships, and functioning that come with serious illness.
Opening up
ACT encourages psychological contact with emotions as they arise and fade. This encourages emotions to flow as appropriate to circumstance—for example, in response to hearing that a medical test reveals metastases or rules them out. In the moment, this may result in higher or lower distress, depending on the context, while over time, this approach of openness to emotions is thought to result in less emotional load as secondary reactivity (e.g., distress in response to intense emotions) is reduced. Similarly, thoughts are observed as they come into the mind, without attempting to change their content or frequency, and are labeled as thoughts. The rationale, in part, is that attempts to avoid or escape from negative thoughts may be subject to the paradoxical effects of thought suppression (Abramowitz, Tolin, & Street, 2001). For example, the person who tells himself “don't think about cancer recurrence” may end up thinking about it more frequently over time due to the growing momentum of the rebound effect (Wenzlaff & Wegner, 2000). A preoccupation with these troubling thoughts interferes with present awareness and enjoyment in everyday life.
Doing what matters
ACT encourages the clarification of personal values, along with acting on what is meaningful and purposeful to the individual. Values may give direction to actions in a variety of life domains, including relationships with others, work, self-development, and health. Values or personal priorities are chosen by each person and may change over time. Clarification and awareness of personal values is important, as ACT teaches the person to be willing to experience difficult experiences that may arise while engaging in behaviors that are aligned with their values (Hayes, Strosahl, et al., 2011).
Committed action in ACT refers to engaging in values-consistent patterns of action on an ongoing basis (Harris, 2006)—for example, eating well and exercising in the service of the value of health and well-being not just once, but regularly, over months and years—and returning to action based on one's core values if a lapse has occurred. Values-consistent activities and behaviors may change over the course of cancer diagnosis and treatment as symptoms such as pain and fatigue may interfere with physical mobility and cognitive functioning. As a result, people are encouraged to be flexible as to how they express their values—for example, acting on the value of connecting with a partner could be achieved with a small act (such as holding hands) or a larger act (such as making dinner or going on a trip), depending on the patient's energy level and ability at any given time. The fundamental premise is that valued action is always possible, even in very challenging and limiting circumstances, and acting on what matters brings richness and meaning to all of our lives, even when pain and distress are present.
In summary, these three processes have been brought together into one sentence that encapsulates the ACT approach to dealing with life's challenges: “I am here now, accepting the way I feel, noticing my thoughts, while doing what I care about” (Moran, 2013). This stance can be applied to every stage of the cancer journey.
ACT in contrast to Cognitive Behavioral Therapy
Overview of CBT
The most common form of psychotherapy used to reduce distress and improve quality of life in cancer patients is Cognitive Behavioral Therapy (CBT; Uitterhoeve et al., 2004; Williams & Dale, 2006). CBT built on the behavior therapy tradition by formally addressing the role of language and cognition (Beck, 1970). Beck (1993) hypothesized that psychological disturbances were caused by inaccurate and problematic thinking patterns, and therefore CBT was developed to apply the “cognitive model of a particular disorder with the use of a variety of techniques designed to modify the dysfunctional beliefs and faulty information processing characteristic of each disorder” (p. 194). Most previous research on psychosocial oncology interventions has focused on psychoeducational interventions and/or cognitive approaches (Newell et al., 2002; Williams & Dale, 2006).
In the last 15 years, several meta-analyses and systematic reviews have reported on the efficacy of cognitive behavioral approaches, showing that CBT positively affects depressive symptoms (Williams & Dale, 2006), reduces emotional distress, and improves quality of life (Osborn, Demoncada, & Feuerstein, 2006) at various points in the cancer-care trajectory (Newell et al., 2002; Uitterhoeve et al., 2004). A meta-analysis by Osborn et al. (2006) showed that short-term CBT significantly reduces symptoms of depression (g = 1.21) and anxiety (g = 1.99) and improves quality of life (g = 0.91), although long-term improvements were only found for quality of life (d = 0.26). CBT protocols can be delivered through individual or group psychotherapy with a variable number of sessions (e.g., 1–52; Johannsen, Farver, Beck, & Zachariae, 2013; Newby, Graff, Ganzini, & McDonagh, 2015).
Key similarities between ACT and CBT
ACT is a form of CBT in the sense that it is part of the evolving tradition of cognitive behavioral approaches, and it utilizes core behavioral components of CBT such as behavioral activation and exposure. Although ACT is a form of CBT, ACT is often contrasted with CBT for ease of communication—for example, in randomized controlled trials when the ACT approach is being compared to the form of CBT originally developed by Beck (Arch et al., 2012; Forman et al., 2007; Wetherell et al., 2011). For the purpose of clarity, we will follow the practice of contrasting ACT with CBT, where by CBT, we mean the form of CBT developed originally by Beck and colleagues.
Despite differences in style and technique, ACT and CBT are thought to have many overlapping mechanisms of change and outcomes. Mennin, Ellard, Fresco, and Gross (2013) suggest that all cognitive behavioral therapies, including CBT and ACT, share a common goal of promoting “behavioral adaptation,” an organism's ability to change to better suit the environment (Dobzhansky, 1970). They suggest that both ACT and CBT foster change through principles of (1) context engagement, or developing new ways of thinking and new behaviors (including behavioral activation and exposure); (2) attention change, i.e., developing the ability to shift and broaden attention (including mindfulness and acceptance); and (3) cognitive change, including shifting perspectives on how a situation is understood (e.g., using cognitive reframing and/or decentering). The commonalities between CBT and ACT is supported by the finding that even with differing theoretical lineages and explicit goals of both ACT and CBT, recipients of both therapies benefit from improvement on a wide variety of outcomes that are not always specifically targeted with the intervention, such as symptom reduction and living a more value-oriented life (Arch & Craske, 2008).
Key differences between ACT and CBT
ACT is one of several behavioral interventions developed since the 1980s that incorporates mindfulness and acceptance-based strategies (others include Dialectical Behavior Therapy, Mindfulness-Based Stress Reduction [MBSR], and Mindfulness-Based Cognitive Therapy [MBCT]). The full explication of the differences between ACT and CBT are beyond the scope of this paper (see Ciarrochi and Bailey [2008] for an explanation of ACT geared toward CBT practitioners); however, we will highlight several differences that are relevant to behavioral treatment of patients living with cancer.
In contrast to CBT, ACT is considered to be transdiagnostic, targeting universal psychological processes that are conceptualized as underpinning psychological suffering across disorders and life challenges. This reduces the emphasis on diagnosis-specific manuals (e.g., for major depressive disorder or generalized anxiety disorder) that are more frequently used with CBT. Most importantly, the transdiagnostic model is well suited to addressing the high levels of psychological and medical comorbidities that occur in cancer populations (Arch et al., 2012; Hayes, Strosahl, et al., 2011; Kadan-Lottick, Vanderwerker, Block, Zhang, & Prigerson, 2005; Mehnert & Koch, 2008). For example, avoidance of bodily discomfort, uncomfortable emotions, and distressing thoughts can be targeted simultaneously and efficiently with experiential exercises that cultivate the skill of acceptance, which can improve mood, illness coping, and functioning even in very brief interventions (Dindo, 2015).
Following a cancer diagnosis and during treatment, patients are faced with life-changing decisions and concerns not only regarding their treatment but also about their future and their families' future (Arman & Rehnsfeldt, 2003; Brooks, Wilson, & Amir, 2011; Singer, 2014). Many patients also have to confront their mortality (Zafar, Alexander, Weinfurt, Schulman, & Abernethy, 2009). The cognitive approach emphasizes challenging distorted and negative thinking patterns and fostering a more balanced perspective (Beck, 1993); however, negative thoughts regarding cancer treatment, prognosis, and personal losses in valued life domains such as work and relationships may not be distorted. The thoughts, moods, and sensations people with cancer experience when confronted with these issues may be accurate appraisals of their present circumstances. For example, a patient endorsing the thought “I might die” and “my family will be devastated” may be true and therefore a cognitive restructuring approach may not be the best fit for this clinical context. This concern regarding fit between the cognitive model and the lived experience of the cancer patient has, in part, led to increasing interest in acceptance-based therapies, as they offer an alternative mechanism of change that emphasizes changing the relationship with negative thoughts and emotions (Shennan, Payne, & Fenlon, 2011; Veehof, et al., 2011) rather than attempting to change the thoughts and emotions themselves.
ACT in contrast to MBSR and MBCT
Overview of MBSR and MBCT
The most commonly used mindfulness interventions in cancer settings are currently Mindfulness-Based Stress Reduction (MBSR) and Mindfulness-Based Cognitive Therapy (MBCT; Shennan et al., 2011). MBSR was developed to help people with chronic health conditions cope with difficult physical symptoms that did not improve with standard medical care, with the early work focusing on chronic pain (Kabat-Zinn, 1982). As a result, instead of aiming to eliminate pain, the goal of MBSR is to foster self-regulation using mindfulness, where mindfulness is defined as “paying attention in a particular way; on purpose, in the present moment, and non-judgmentally” (Kabat-Zinn, 1994, p. 4). Suffering is proposed to be reduced by developing a stance of neutral, open awareness, which allows for acceptance of pain sensations, as well as pain-related thoughts and emotions, without struggle, rumination, or negative evaluation (e.g., “this pain is horrible”). Committed mindfulness practice is associated with the uncoupling of the sensory and affective/cognitive aspects of pain (Grant, Courtemanche, & Rainville, 2011), so that although pain may remain, suffering is reduced. Due to the emphasis on living with difficult, distressing, and often unavoidable physical symptoms, MBSR has been used with increasing frequency for cancer patients and can improve psychosocial health and cancer adjustment (Cramer, Lauche, Paul, & Dobos, 2012; Ledesma & Kumano, 2009).
More recently, MBCT was developed to help integrate the principles of CBT with MBSR to better prevent depression relapse (Segal, Williams, & Teasdale, 2012; Teasdale et al., 2000). Teasdale et al. (2002) proposed a model of cognitive vulnerability whereby some individuals are more susceptible to experiencing low mood, which can lead to a pattern of negative thinking, in turn perpetuating and intensifying low mood and ultimately leading to a state of depression. In this way, individuals who have experienced a prior episode of depression are more vulnerable to experiencing a relapse. The proposed therapeutic mechanisms of MBCT include awareness and acceptance of present moment experience in order to teach patients to relate differently to their thoughts, emotions, and behaviors and interrupt key processes that contribute to worsening mood. Due to high levels of comorbidity between cancer diagnoses and mental health concerns (notably anxiety and depression; Mitchell et al., 2011), MBCT has been applied in oncology settings and can successfully reduce symptoms of cancer-related fatigue, anxiety, depression, and distress (Foley, Baillie, Huxter, Price, & Sinclair, 2010; Shennan et al., 2011; van der Lee & Garssen, 2012). Furthermore, a recent review of 13 articles found that mindfulness interventions (i.e., MBSR or MBCT) show promise in both acute and palliative oncology settings, notwithstanding methodological limitations associated with some of the studies (Shennan et al., 2011).
The practice of mindfulness itself is associated with distinct physiological effects including an increase in parasympathetic nervous system activation (Ditto, Eclache, & Goldman, 2006; Azam et al., 2015). Although the intention of mindfulness practices is not to relax but rather to bring attention to present moment experiences, a sense of relaxation is a commonly reported outcome of regular practice (Baer, 2003). The benefits of mindfulness practice may contribute to the overall improvement in parasympathetic nervous system activation, such as respiratory sinus arrhythmia (Ditto, Eclache, & Goldman, 2006; Azam et al., 2015), decreased skin conductance response (Ortner, Kilner, & Zelazo, 2007), and long-term decreased cortisol, proinflammatory cytokines, and blood pressure after MBSR in cancer patients (Carlson, Speca, Faris, & Patel, 2007). Changes in physiological processes may underlie the reduction of distressing physical symptoms that cancer patients experience with mindfulness practice, including reduced stress, pain, and fatigue and improved sleep (Carlson & Garland, 2005; Tacon, 2011).
Key similarities between ACT and MBSR/MBCT
Like MBSR and MBCT, ACT teaches core principles of mindfulness. Mindfulness has been proposed to reduce distress through (1) exposure to uncomfortable experiences, (2) understanding that thoughts are thoughts, (3) increasing engagement with coping skills, and (4) practicing momentary acceptance of difficult thoughts, emotions, and physical sensations (Baer, 2003). Both ACT and MBSR/MBCT share the core principle of acceptance, which emphasizes turning towards rather than away from emotional, cognitive, and physical pain. Therefore, both interventions promote exposure by encouraging individuals to remain in contact with, rather than avoid, difficult physical, cognitive, and emotional experiences, which can facilitate desensitization to the distressing emotional response. Furthermore, MBSR/MBCT and ACT teach a shift in perspective that involves bringing awareness to thoughts and feelings as mental events, which has been referred to as “decentering” (Baer, 2003). Decentering can lead to a change in the way internal experience is perceived, as emotional or physical pain can shift from a “primary” experience to a “secondary” experience through the act of contemplating it (Shapiro, Carlson, Astin, & Freedman, 2006). This shift is considered to be a central mechanism that drives the clinical effectiveness of mindfulness practice and has been described in mindfulness-centered writing as “reperceiving” (Shapiro et al., 2006), “decentering” (Teasdale et al., 2002), and in ACT writing as “self-as-context” (Hayes et al., 1999).
Key differences between ACT and MBSR/MBCT
ACT differs from MBSR and MBCT in the structure and delivery of therapy. The structure of MBSR and MBCT both require that patients attend weekly two-hour group sessions, although the duration varies slightly according to specific study protocols (Kabat-Zinn, 1982; Teasdale et al., 2000; Veehof et al., 2011). Each week, patients are assigned homework that requires up to 45 minutes of home-based mindfulness practice approximately six times a week, typically using audio recordings provided by the facilitators (Kabat-Zinn, 1982; Teasdale et al., 2000). The time commitment and structure leads to high demands on patients that may be challenging to fulfill in conjunction with logistical demands of cancer treatment and the symptom burden experienced. For example, Teunissen et al. (2007) found that more than 50% of patients reported fatigue, pain, lack of energy, weakness, and no appetite over the course of treatment, with cognitive difficulties an additional notable complaint. These adverse effects of cancer treatment may interfere with weekly group attendance and the ability to complete the assigned home practice.
The three core pillars of ACT can be modeled, taught, and experienced using a host of techniques, including experiential exercises, metaphors, and clinical interactions. ACT is scalable; therefore, the number, length, format, and content of sessions vary considerably. ACT treatment protocols have been effectively modified to be shorter or longer in length, depending on the needs of the patient population. For example, shorter protocols have been developed to target individuals with chronic pain using four weekly one-hour sessions (Dahl, Wilson, & Nilsson, 2004); medical patients with a one-day workshop (Dindo, 2015); or primary care patients in distress in as little as one session (Strosahl, Robinson, & Gustavsson, 2012). In contrast, McCracken, MacKichan, and Eccleston (2007) created a three-week, full-time intervention (80 hours) to better target the intensive rehabilitation needs of patients who were highly disabled from chronic pain. Other protocols fit more standard psychotherapy delivery models, such as 12 individual, face-to-face meetings with a psychotherapist (Arch et al., 2012; Rost, Wilson, Buchanan, Hildebrandt, & Mutch, 2012).
ACT teaches aspects of mindfulness such as being present in the moment, noticing thoughts and feelings, and letting go of judgements; however, ACT therapists often rely on experiential exercises and metaphors to teach this content, rather than training these skills by asking patients to practice formal mindfulness meditation for 40 minutes per day, as is often the case in MBSR and MBCT. Home practice of meditation can be part of ACT, but it not a mandatory component of the intervention. Rather, ACT emphasizes “informal” mindfulness practice by attuning to “five senses experiences” while doing daily activities, such as washing dishes and eating meals (Hayes, Strosahl, et al., 2011). This flexible structure may be better suited for people undergoing cancer treatment and experiencing the adverse effects noted above. Additionally, ACT emphasizes active, ongoing exploration of the person's values, along with behavioral steps toward acting on what is important, both of which are not explicitly a focus of MBSR or MBCT (though acting with awareness and intention in the moment are closely related and are explicitly discussed). This provides a new avenue for present life fulfillment that might not otherwise be explored.
Methods
Narrative review search strategy and study selection
A literature search was conducted to determine evidence for the use of ACT in oncology settings using the following search terms: acceptance and commitment therapy, ACT, cancer, and oncology. Database searches were conducted in March 2016 using CINAHL, PubMed, and PsycINFO. To the authors' knowledge, only one case study (Karekla & Constantinou, 2010), three pre-post cohort studies (Arch & Mitchell, 2015; Burke et al., 2014; Feros, Lane, Ciarrochi, & Blackledge, 2013), and two randomized controlled trials (Hawkes, Pakenham, Chambers, Patrao, & Courneya, 2014; Rost et al., 2012) have been published using ACT with cancer patients or family members. Although three articles discussing an ACT intervention in women with breast cancer were reported by Hulbert-Williams, Storey, and Wilson (2015), translated versions of the articles were not available to be included for the present review (Montesinos, Hernandez, & Luciano, 2001; Montesinos & Luciano, 2005; Páez, Luciano, & Gutiérrez, 2007). Studies were not included in the review if they used qualitative methodology (Nelson et al., 2015) or were of poor quality (i.e., reported the same data in multiple studies, used treatment protocols with substantial deviation from existing ACT protocols, and/or reported inadequate statistical analysis; Datta, Aditya, Chakraborty, Das, & Mukhopadhyay, 2016; Esmali & Alizadeh, 2016; Gholamhosseini & Mojtabaie, 2015; Mohabbat-Bahar, Maleki-Rizi, Akbari, & Moradi-Joo, 2015; Mojtabaie & Gholamhosseini, 2014; Najvani, Neshatdoost, Abedi, & Mokarian, 2015). Treatment protocols were considered to be substantial deviations if there was an insufficient description of the treatment protocol and/or if concepts that are inconsistent with ACT treatment were introduced.
Results
Study characteristics
The six studies were conducted using a variety of cancer diagnoses: breast cancer (N = 1; Karekla & Constantinou, 2010), ovarian cancer (N = 47; Rost et al., 2012), colorectal cancer (N = 410; Hawkes et al., 2014), or mixed cancer populations (N = 42; Arch & Mitchell, 2015; N = 11; Burke et al., 2014; N = 45; Feros et al., 2013). In three studies, distress was used as an inclusion criterion for participating (Arch & Mitchell, 2015; Feros et al., 2013; Karekla & Constantinou, 2010). Two studies included participants who had advanced disease symptoms, which comprised of all participants for Rost et al. (2012) and 11% of the sample for Feros et al. (2013). Only one study did not investigate the patients themselves, but rather the parents of children that had a diagnosis of cancer or underwent major heart surgery (Burke et al., 2014).
Format of interventions
The interventions varied in delivery structure, length, and medium. Individual therapy was administered in 8–12 sessions that ranged in length from approximately 30 minutes to 1 hour (Feros et al., 2013; Hawkes et al., 2014; Karekla & Constantinou, 2010; Rost et al., 2012). Group sessions ranged between 5 and 7 sessions and were between 1.5 and 2 hours in length (Arch & Mitchell, 2015; Burke et al., 2014). All interventions were administered in person, with the exception of one study that was administered over the phone (Hawkes et al., 2014). Although the content of study protocols varied in the format delivered, they all covered the three pillars of psychological flexibility of the ACT model. Hawkes et al. (2014) additionally emphasized healthy lifestyle change, explicitly promoting increased physical activity, eating a healthy diet, and smoking cessation (Hawkes et al., 2009). In most cases, the protocols described the use of experiential exercises and metaphors.
Only two studies were randomized and controlled (Hawkes et al., 2014; Rost et al., 2012) in which participants were randomized to either the intervention or provided with treatment as usual. In the study by Rost et al. (2012), the “treatment as usual” condition used a 12-session protocol that included psychological support by teaching relaxation techniques, problem solving skills, and cognitive restructuring, key elements of standard CBT protocols for cancer patients. In contrast to mindfulness exercises, the intention of the relaxation techniques was to calm the body and mind, which may reduce tension and/or serve as a distraction (Jain et al., 2007). For Hawkes et al. (2014), the “usual care” condition included the dissemination of four educational brochures and quarterly newsletters related to the study content.
Outcome measures
All studies collected outcome measures at pre- and posttreatment, with five studies also collecting additional follow-up data at three months (Arch & Mitchell, 2015; Feros et al., 2013; Karekla & Constantinou, 2010), six months (Burke et al., 2014; Hawkes et al., 2014; Karekla & Constantinou, 2010), and 12-months (Hawkes et al., 2014). Rost et al. (2012) also assessed outcomes after the fourth and eighth sessions, although they were not able to include a long-term follow-up as many of their advanced disease patients had died. Although the specific outcome measures used varied across studies, most included a measure of distress and psychological flexibility. Only one study included physical pain as an outcome measure using the short form of the Medical Outcomes Study questionnaire (SF-36). In the case study conducted by Karekla and Constantinou (2010), no specific outcome measures were used, but the patient reported that at the end of treatment, she felt “like her old self” (p. 379).
Treatment effects
Due to the disparate study designs used in the included studies, treatment effects are considered separately below according to pre-post cohort studies and randomized controlled trials.
Pre-post cohort studies
Feros et al. (2013) found significant changes with medium to large effect sizes (d = 0.56 to 1.38) at the posttreatment and three-month assessments, whereby distress and mood disturbance decreased and quality of life and psychological flexibility increased. They reported that ACT had comparable efficacy to similar psychotherapeutic interventions, such as CBT (Feros et al., 2013; Osborn et al., 2006). Similarly, Arch and Mitchell (2015) found significant changes at posttreatment and the three-month follow-up, including a decrease in anxiety, depression, fear of cancer recurrence, physical pain, and trauma symptoms, as well as an increase in vitality, life meaning, comprehensibility, and manageability. Burke et al. (2014) reported significant reductions in posttraumatic stress symptoms and an improvement in the emotion adjustment to the diagnosis, psychological flexibility, and mindfulness.
Randomized controlled trials
Rost et al. (2012) found significant interaction effects for all outcome measures assessed. They showed that for measures of distress, quality of life, and acceptance, patients in the ACT treatment group improved over the course of treatment while those in the treatment as usual group (using a CBT-style protocol) did not. For measures of mental disengagement, emotional control, and thought suppression, interaction analyses over the course of treatment showed significant worsening in the treatment as usual group and significant improvements in the ACT treatment group. For measures of anxiety and depression, both the treatment as usual and ACT treatment group showed an improvement of symptoms, although this effect was significantly greater for the ACT treatment group.
Hawkes et al. (2014) found treatment effects for the ACT intervention in comparison to usual care for posttraumatic growth and the cancer-specific quality of life subscale of physical well-being at both 6 months and 12 months, whereas treatment effects were only evident for spirituality and acceptance at 6 months. For measures of mindfulness and distress, both the ACT intervention and usual care showed significant improvements, but did not significantly differ from each other. Mediational analyses further showed that outcomes assessing ACT variables (acceptance and mindfulness) indirectly affected measures of posttraumatic growth, spirituality, and quality of life (physical well-being) 6 months following treatment.
Discussion
The results of the current narrative review demonstrate that there is a small body of empirical research available on the use of ACT with cancer patients. Furthermore, only two published studies were randomized controlled trials, which are considered the gold standard for evidence-based research (Cartwright, 2011). Further research with a randomized, controlled design would meaningfully contribute to the growing body of evidence of ACT's effectiveness with cancer patients. It is notable that the included studies were diverse: they were conducted in various cancer settings, with nonrestrictive inclusion criteria, at various stages of treatment, and delivered with different protocols. The differences in intervention delivery and format demonstrate how ACT protocols are flexibly incorporated into clinical settings to accommodate the needs of the patient, such as for high-functioning colorectal cancer survivors (Hawkes et al., 2014) or patients receiving end-of-life care (Rost et al., 2012).
The included studies showed significant improvements for a variety of psychological variables. Of particular interest is the significant improvement in mindful attention found by Burke et al. (2014), given that participants were not assigned mindfulness home practice, as in MBSR and MBCT interventions. Similarly, the clinical improvements found by Rost et al. (2012) are notable given that participants were in the late stage of ovarian cancer, which can be associated with distress that remains stable or increase over time (Hipkins, Whitworth, Tarrier, & Jayson, 2004). Furthermore, of the 47 patients who were recruited, 16 participants were unable to complete the protocol as they passed away (n = 12) or needed to be transferred to home-based hospice care (n = 4), demonstrating the large effect sizes of the ACT treatment for patients in the late stages of disease progression. This suggests that ACT may be a particularly good fit for the needs of patients nearing end of life. Although only one study included an outcome measure for physical pain (Arch & Mitchell, 2015), it is noteworthy that the magnitude of improvement for physical pain was medium to large, providing some support for the effectiveness of an ACT intervention for cancer pain. All but one study included follow-up data ranging from 3 to 12 months. This shows the long-term efficacy of the treatments for sustained changes in measures of quality of life, distress, mood, and psychological flexibility. Taken together, although there is limited research available on the use of ACT interventions in oncology settings, the available evidence shows that ACT can be an effective psychological intervention to reduce distress and improve quality of life for cancer patients.
Future directions
Presently, there are few published research studies that investigate the use of ACT interventions in oncology settings (Hulbert-Williams et al., 2015; Shennan et al., 2011). The present narrative review offers preliminary evidence that supports the use of ACT in psycho-oncology settings. This may be due to its emphasis on acceptance of distress and difficult body sensations like pain, as well as finding meaning, purpose, and direction in the midst of highly challenging circumstances. ACT interventions may be particularly well suited to oncology settings since the ACT model can be applied transdiagnostically to target many varieties of psychological difficulties and ACT protocols can be adapted with great flexibility to serve the specific needs of different cancer-related populations (e.g., with respect to length, duration, format, and emphasis of intervention). Furthermore, ACT has shown strength in addressing a variety of challenges relevant to people diagnosed with cancer, such as pain (McCracken & Vowles, 2008), health behavior change (Gregg et al., 2007), distress reduction (Arch & Craske, 2008), and improvement in physical functioning (Vowles et al., 2007). However, in order to be implemented more broadly in cancer settings, stronger empirical evidence of efficacy and an examination of cost-effectiveness are needed (Owen, Klapow, Hicken, & Tucker, 2001).
Future research should consider further explorations of ACT interventions in various cancer populations across the illness trajectory. The present study provides support that ACT interventions have been effective for patients with breast, ovarian, and colorectal cancer and it would be important to conduct larger scale investigations of any differential effects for cancer types and stages. As only two studies included patients during the late stage of illness (Feros et al., 2013; Rost et al., 2012), it would be useful to replicate these findings in larger trials and to investigate other stages of illness, such as immediately following diagnosis.
The burden of cancer diagnosis and treatment also affects the caregivers and family members of cancer patients, at times causing substantial psychosocial distress (Mitschke, 2008). The present review identified only one study that targeted the parents of children with cancer or following major heart surgery (Burke et al., 2014). Future research should consider utilizing ACT for other individuals involved in the care of the patient. ACT interventions have been used effectively with other caregiver populations, such as parents of children with autism (Blackledge & Hayes, 2006), supporting the investigation for its use in this population. Finally, many of the included studies did not measure constructs that are specifically targeted by ACT interventions, such as sense of purpose and meaning or daily functioning: inclusion of these variables may provide a more suitable index of change in future research. It is possible that focusing on distress reduction as the primary outcome may lead to an underestimation of the long-term impact of ACT and other interventions on quality of life or functioning if not directly measured (Newell et al., 2002; Osborn et al., 2006; Williams & Dale, 2006). When more evidence is available, meta-analytic reviews may be useful in better determining the efficacy of ACT interventions in oncology settings.
There are substantial barriers to implementing psychological interventions in healthcare settings, reflected in the substantial gap between recommended practices in cancer-care and real-life practice (Schofield, Carey, Bonevski, & Sanson-Fisher, 2006). Dilworth, Higgins, Parker, Kelly, and Turner (2014) completed a systematic review of 25 papers that evaluated barriers for psychosocial care. For patients, the most commonly reported barriers were the perception that psychosocial care is not needed, lack of information, means of access, lack of confidence in services, and negative perception by others. Commonly reported perceived barriers by health professionals included lack of time and resources, negative perceptions of psychosocial care (such as lack of scientific validity), lack of knowledge of resources, and cost. Importantly, structural barriers such as a lack of funding also provide a logistical barrier in the provisions of psychosocial care to patients (Holland & Bultz, 2007; Holland, Kelly, & Weinberger, 2010). These barriers need to be carefully considered in implementing ACT interventions in oncology settings and applications such as brief workshops or interventions with internet-based components may have high impact at low cost.
Conclusion
Receiving a diagnosis and treatment for cancer can affect all aspects of a person's life, including relationships, economic stability, and physical and psychological well-being. High levels of distress and physical symptoms, especially pain, are reported in people with cancer and many continue to struggle to cope with the treatment and diagnosis years later. There is support for the use of psychotherapy to treat symptoms of depression in oncology settings. Most research has focused on CBT approaches, although more recently, mindfulness and acceptance-based approaches have increased in popularity. The ACT approach may be particularly well suited for use in medical settings due to its focus on the acceptance of difficult thoughts, feelings, and sensations, rather than on trying to reduce symptomology of an underlying psychological “disorder” and due to its success in other domains of behavioral medicine including chronic pain. The results of the present narrative review show that despite the 30-year history of ACT, few empirical studies have investigated the efficacy of ACT interventions for people with cancer, including one case study and five intervention trials. The studies examined a diverse range of patient populations, including breast cancer, ovarian cancer, colorectal cancer, and mixed cancer at various stages of disease progression. Overall, the findings suggest that ACT can be an effective psychotherapeutic intervention for use in oncology settings, showing a decrease in symptoms including distress, mood disturbances, trauma and physical pain as well as improved quality of life and psychological flexibility. Future research should evaluate larger scale studies in different cancer populations across the illness trajectory. Considerations for further trials for individuals, groups, and technology-mediated (e.g., telephone, internet) modalities, as well as with families, significant others, and caregivers are warranted. In implementing interventions, perceived barriers related to patients and health professionals and as well as institutional obstacles should be addressed.