The study has two arms: 1) MBCT delivered by teleconference over eight weekly sessions and (2) patient education.
It is hypothesised that 3, 6 and 9 months after recruitment and commencement of the intervention:
1. Relative to men who receive patient education, men who receive MBCT will have lower anxiety and depression.
2. Relative to men who receive patient education, men who receive MBCT will have lower cancer-specific distress.
3. Relative to men who receive patient education, men who receive MBCT will have higher mindfulness.
4. Intervention-driven improvements in psychological outcomes will be mediated by mindfulness skills.
Patient education consists of the man’s standard medical management and a package containing existing evidence-based patient education materials.
Mindfulness-Based Cognitive Therapy
The Mindfulness-Based Cognitive Therapy group intervention (MBCT) follows a cancer-specific manual based on Segal, Williams and Teasdale’s [15
] manual for MBCT, with novel specific components developed for men with advanced prostate cancer in our pilot study [14
]. The sessions are facilitated by health professionals with experience in oncology and professional training in MBCT. The program has been further developed to be suitable for telephone delivery. For example, facilitators have been trained to use explicit communication such as encouraging group members to say their name before contributing, listen closely to the tone of participants' voices, give extra time for responses, and have explicit rules for how the group will interact. Each session runs for 1.25-h and only short (up to 15 min) meditations are provided during the group phone sessions to support group engagement and alleviate practical concerns such as holding the telephone receiver. As well, the material in participant workbooks has been elaborated to provide session plans, so participants can navigate phone sessions more easily, and interactive worksheets are provided to help keep group discussions on task. The program includes eight weekly group teleconferences, and each participant has an individual introductory call with their facilitator to allow them to connect with the facilitator, prepare them for the program and to enhance motivation. Participants are provided with a handbook summarising each weekly session; self-help materials including Jon Kabat Zinn’s Full Catastrophe Living [16
]; and an audio recorded meditation on compact disc. Daily home practice of mindfulness meditation is strongly encouraged; with participants asked to engage in one of the four 35 min practices depending on the stage of the course (the body scan, moving meditation, mixed mindfulness meditation, silent practice with bells at 5 min intervals). Finally, as in our pilot study, peer interaction is directed towards support for the learning of mindfulness skills and mutual support in facing the challenges of advanced prostate cancer.
Recruitment is being undertaken through clinicians in the Australian and New Zealand Urogenital and Prostate Cancer Trials Group and in major treatment centres in Queensland, New South Wales, Victoria and Western Australia. Other recruitment avenues include the distribution of information through prostate cancer support groups and media promotion. The research team who contact potential participants after referral to the study obtains informed written consent. Figure illustrates the recruitment, intervention and data collection process.
Flowchart of recruitment, intervention and assessment.
Inclusion criteria are that the men must: (1) have proven metastatic disease or castration resistant biochemical progression; (2) be able to read and speak English; (3) have no previous history of head injury, dementia or psychiatric illness; (4) have no other concurrent cancer; (5) have phone access.
Approximately 190 men will be recruited to the study (allowing 30% attrition from treatment; 65 men in each condition will complete final assessments). This sample size would comfortably exceed 80% power to detect a moderate to large effect over four assessment points.
Ethical approval has been obtained from the Griffith University Human Research Ethics Committee (Approval: PSY/15/12/HREC) and Metro-North – The Prince Charles Hospital Human Research Ethics Committee (HREC/12/QPCH/101). The study design is guided by the CONSORT criteria [17
]. Randomisation to study condition occurs following the completion of baseline assessment. Assessments are by self-report pen and paper measures and project staff tracking assessments are blinded to condition where possible. Randomisation occurs in blocks of 14, with each condition randomly generated 7 times within each block to ensure an unpredictable allocation sequence with equal numbers of men in each condition at the completion of each block; and sufficient men to form a tele-based group (of 7) in the MBCT condition. Randomisation occurs within Queensland-Western Australia and New South Wales-Victoria dyads to coincide with a two-stage commencement of recruitment. The randomisation sequence is undertaken by the project manager and concealed from investigators. The group sessions are audiotaped with 15% reviewed to ensure adherence to an MBCT approach. Analyses will be conducted on the basis of intention to treat.
A series of previously validated and reliable self-report measures are administered by mail to men at four time points: baseline/recruitment and at 3, 6, and 9 months after recruitment and intervention commencement. Mindfulness skills are included as potential mediators of intervention effect. Primary outcomes are anxiety, depression and cancer-specific distress. Secondary outcomes are global QoL and benefit finding. Disease variables (e.g. cancer grade, stage, time since diagnosis, time since treatment) will be assessed through medical records review.
Mindfulness: The Five Facet Mindfulness Questionnaire (FFMQ) [18
] is being used to measure the participants’ engagement with the principles of mindfulness.
Adherence to Practice: Adherence to mindfulness practice is assessed by participants completing a daily home practice form.
Primary outcome variables
Anxiety and Depression: The Brief Symptom Inventory-18 [19
] is providing a global measure of current psychological distress with subscale scores for anxiety, depression, and somatisation.
Cancer-Specific Distress: The Impact of Events Scale (IES) [20
] and the PSA Anxiety subscale of the Memorial Anxiety Scale for Prostate Cancer (MAX-PC) [22
] is being used to measure men’s cancer-specific distress.
Secondary outcome variables
Quality of Life: The Functional Assessment of Cancer Therapy – Prostate (FACT-P) [23
] is being used to assess the men’s perceived global quality of life across 5 domains: physical, social/family, emotional, functional well-being, and prostate cancer-specific concerns.
Benefit Finding: Positive adjustment is being measured with the Posttraumatic Growth Inventory assessing perceived positive outcomes resulting from a diagnosis of cancer [24
The study is a two-condition randomised controlled trial with repeated measures across time and continuous outcome variables. The analysis of longitudinal differences in outcome will be by multilevel (mixed) modelling (MLM). These procedures allow the testing of typical group level predictions such as Hypotheses 1 to 3 that men in the intervention condition will have better outcomes than the patient education group. However, by incorporating the hierarchical structure of assessment points nested within individual men they further permit the true assessment of individual change in psychological outcomes and of potential mediators of such change (Hypothesis 4). Consequently (and unlike traditional approaches), this model deals with the heterogeneity of responses, such as that expected in the outcomes of the proposed study, by allowing such variation as random effects within the model. MLM has the advantage of allowing use of all available data points, which maximizes power to detect effects and reduces bias owing to missing data in longitudinal studies.