Study protocol of the CAREST-trial: a randomised controlled trial on the (cost-) effectiveness of a CBT-based online self-help training for fear of cancer recurrence in women with curatively treated breast cancer

Due to earlier diagnosis and improved medical treatments, the number of women living with breast cancer is rising. In the Netherlands, the prevalence of breast cancer has been estimated to rise from 100.000 in 2000 to 140.000 in 2020 [1]. Similarly, in the USA, the 5-year relative survival rate of women with breast cancer improved from 75 % in 1975 to 90 % in 2009 [2]. One of the most prevalent long-term consequences of surviving cancer is fear of cancer recurrence (FCR), which can be defined as the fear or worry of the possibility that the cancer will return or progress in the same organ or in another part of the body [3]. Although the majority (82 %) of long-term breast cancer survivors reported low levels of FCR, a considerable amount of women (17 %) reported moderate to high FCR [4]. In younger (age 18–45) early-stage breast cancer survivors, 70 % of participants report moderate to high levels of FCR [5]. Younger age was also found to be associated with a higher intensity of FCR [5, 6]. Moderate to high levels of FCR have also been found in 29 % of women with ductal carcinoma in situ or early invasive breast cancer two years after diagnosis [7].

Findings on the long-term course of FCR are still unclear [8]. Thewes and colleagues [9] found longer time associated with reduced FCR in younger cancer patients. Several other studies found no significant relationship between time since diagnosis and FCR [3, 10‐15]. Elevated levels of FCR represent a continuing problem in cancer patients, up to sixteen years after diagnosis [3, 10‐15]. For example, long-term breast cancer survivors (5–12 years after diagnosis) report many factors that can trigger FCR, such as hearing about cancer, unclear bodily complaints, environmental triggers (e.g., on television, the internet, newspapers, and magazines; and visiting a doctor [16]. Women encounter these triggers about twice a month [16].

Thus, FCR is a common and continuing problem in breast cancer survivors. Women cope with FCR in different ways. Elevated levels of FCR has been found to be associated with higher frequency of unscheduled visits to the general practitioner, larger number of outpatient and emergency room visits, and more use of health care services [5, 16, 17]. Higher levels of FCR may also lead to avoiding forms of cancer screening and medical control visits [5, 16, 17]. Moreover, FCR may lead to various types of (compulsive) self-examining [5, 16, 17]. Therefore, it is not surprising that preliminary evidence shows that FCR is associated with higher healthcare costs and lower surveillance rates, which may compromise health outcomes [5].

Depending on the coping mechanisms used by breast cancer survivors to deal with their FCR, FCR also has a considerable impact on their lives. One of the most significant effects of FCR is the negative impact on quality of life [4, 18, 19]. Furthermore, FCR may have a correlation with distress, intrusive thoughts, avoidance, hyperarousal, psychological disorders (e.g., depression, anxiety symptoms, posttraumatic stress disorder), and fatigue [3, 4, 13, 14, 20]. Subsequently, FCR is associated with higher mental health costs [5, 19].

Cancer survivors frequently identify FCR as a major concern and 20 to 79 % of them report to have a need for professional help coping with FCR [19, 21]. About 30 % of cancer survivors have indicated that there is no support for them in dealing with FCR [22]. Reasons for this include lack of recognition, lack of trained mental health professionals, insurance coverage and cost issues, and geographical distance from providers [22, 23]. Considering the increasing prevalence of breast cancer, increasing healthcare costs, and the lack of professional help for FCR in a large group of cancer survivors [1, 2, 5], there is an urgent need for easy-accessible and cost-effective evidence‐based psychological interventions for reducing FCR.

Knowledge on treatment of FCR is limited. Simard and colleagues [19] found only five face-to-face group interventions (cognitive behaviour therapy, supportive-experiential therapy, mindfulness-based stress reduction, and emotion regulation) to reduce FCR. Furthermore, Völker and colleagues [24] suggest a stepped-care model for treating FCR. Normalization, psycho-education and self-management are the first steps in this model [24]. Normalization helps patients to understand that fear is a normal reaction which can be helpful in some situations. Psycho-education is necessary, because cancer survivors experience many bodily symptoms (such as fatigue, new aches and pains, muscle tension, joint stiffness, feeling of weakness, indigestion, and other physical symptoms) that can easily be misinterpreted as symptoms of recurrence [16]. Anxiety itself also can cause several bodily symptoms (such as increased heart rate, shortness of breath, chest pressure, sweating, dry mouth, dizziness, feeling of weakness, muscle tension, and indigestion), which may increase other bodily symptoms and therefore reinforce FCR. In extreme cases, FCR has been associated with the development of anxiety disorders [8]. Misinterpretation of bodily symptoms can lead to negative thinking, which causes somatic amplification. Because of this somatic amplification, patients focus even more on their bodily symptoms, leading to a negative emotional spiral. With psycho-education, patients gain more knowledge about the bodily mechanisms of fear. This knowledge can help them to break the negative spiral. Ziner and colleagues [25] found that breast cancer survivors with high self-efficacy in dealing with concerns related to breast cancer after treatment, had lower FCR and that self-efficacy may have a protective effect in these women. Therefore, training in self-efficacy may reduce FCR [24‐26]. If these first steps of treatment for FCR turn out to be insufficient, cognitive behavioural therapy (CBT) should be the next step in the treatment of FCR [24, 27, 28]. Furthermore, acceptance focused therapies, such as Mindfulness Based Stress Reduction (MBSR), Mindfulness Based Cognitive Therapy (MBCT) and Acceptance and Commitment Therapy (ACT) may be included in treatment for FCR [24].

In order to reach the growing group of breast cancer survivors experiencing FCR, a CBT-based online self-help intervention (including normalization, psycho-education and self-management) may be an appropriate and accessible way to offer psychological treatment to patients for several reasons. First, self-help without support was the second most preferred type of supportive care by cancer patients (14–28 %), after individual professional counseling [21]. Furthermore, there is a growing body of evidence that internet interventions can improve psychological well-being in cancer patients [23]. Online self-help interventions have several advantages, including convenience (such as working on the self-help training in the evening when there are no competing demands), ability to proceed at one’s own pace to master the material, low cost, greater privacy and confidentiality, more comfort, the intervention content can be updated quickly, greater accessibility (for example for those living in rural areas), time- and cost-effective, and where waiting lists are long [23, 29‐31]. Convenience and working in their own pace may be particularly attractive for young women, who often are still working and have young children [5]. Given the high prevalence of FCR in young breast cancer survivors, online self-help training may be an effective and attractive way to reach these young women [5]. Moreover, an informational self-management intervention may reduce psychological distress (feelings of tension, anger and depression) in high risk patients who perceive little control and much illness uncertainty [32]. Thus, an online self-help intervention with psycho-education may empower patients. Disadvantages of online self-help interventions are internet access constraints, technical difficulties, high drop-out rates, poor adherence, safety issues, limited personal interaction, and not being able to detect more complicated issues and non-verbal or verbal clues in patients [23, 31, 33, 34]. Furthermore, online cognitive behavioural interventions for anxiety have been found to be effective for anxiety disorders and anxiety symptoms [30, 35]. Online cognitive behavioural self-help interventions for anxiety have been found to be at least as good as face-to-face treatment in several studies, but other studies found small effects favoring face-to-face treatment [29, 34‐37]. Self-help interventions may be specifically effective, if based on a theoretical model such as CBT [38]. In conclusion, CBT-based online self-help interventions are promising and may provide effective, acceptable, and practical health care for those who may otherwise remain untreated. Because online self-help training may be both easily accessible and cost-effective, in the current study an online CBT-based self-help training to reduce FCR after breast cancer treatment will be evaluated.