Being Mindful of Our Ps and Qs: A Systematic-Narrative Review of the Parallels and Quality of Digital Mindfulness-Based Programs for Cancer Patients

A hybrid systematic-narrative approach was employed to comprehensively evaluate the adherence of existing digital MBPs for cancer patients on key elements, as well as compare and contrast these interventions in terms of reported content, delivery, and measured outcomes. While prior literature reviews have primarily focused on evaluating the efficacy of MBPs, this narrative review aimed to provide a deeper understanding of their quality, which may help explain the observed heterogeneity in study outcomes (Greenhalgh et al., 2018). This was achieved through a critical analysis and visual interpretation of MBP content descriptions drawn from original research articles. The article retrieval process was conducted systematically to minimize selection biases and detailed search strategies were outlined (Turnbull et al., 2023). Furthermore, this review adhered to PRISMA guidelines, ensuring a rigorous and transparent approach to the literature search (see Supplement 1 for completed PRISMA checklist).

A total of 35 articles were included in this review. The results of this review have been organized into four domains: (1) assessing interventions as MBPs, (2) intervention delivery, structure and content, (3) cancer patient experiences, (4) review of intervention effectiveness and evaluation methodology.

This review aimed to evaluate the quality of existing digital MBPs for cancer patients by assessing interventions for key elements and comparing program delivery, content, and reported outcomes, which may contribute to previously reported heterogeneity (Fan et al., 2023; Fung et al., 2024; Matis et al., 2020). Overall, the review uncovered that interventions referred to as MBPs in the literature vary considerably inhow faithful they are to key MBP elements, reported details of the program, well-being outcomes assessed, and how interventions are tested/tailored for different patient outcomes. These variations existed despite purporting to follow the same key principles of mindfulness. In particular, one key finding was that most interventions did not meet the criteria to be classified as an MBP, as per the framework developed by Crane et al. (2017); however, those classified as an MBP showed more promise in significantly impacting patient outcomes. Indeed, studies that evaluated first-generation or older adaptations of MBPs such as MBSR, MBCT, and MBCR were more likely to faithfully follow existing protocols, which may explain why these types of interventions demonstrated the most effectiveness in improving a greater number of patient outcomes (Fig. 3). This highlights the importance of standardized program fidelity in ensuring consistent patient outcomes and suggests that newer or modified MBPs should be tested rigorously for adherence to core mindfulness principles. Various inferences and recommendations can be drawn from our findings.

First, researchers should exert caution when labeling programs specifically as MBPs. Amidst the numerous “mindfulness-based” interventions available and being tested on cancer patients, it is essential for scholarly and patient transparency that interventions labeled as MBPs contain the defining features of an MBP, and further, that such features/definitions be agreed-upon standards. Indeed, intervention validity and integrity have been identified as essential elements of effectiveness studies (Crane et al., 2013; Weck et al., 2011). Only then can interventions be meaningfully compared and assessed for effectiveness. We found that one of the most distinctive features of MBPs identified as missing from most MIPs was the systematic and sustained training in formal and informal meditation practices (Crane et al., 2017); yet previous reviews have lumped those with and without this key ingredient in analyses (Fan et al., 2023; Fung et al., 2024; Matis et al., 2020). This oversight may explain some of the heterogeneity in treatment effects reported in systematic reviews conducted to date.

Second is the need for greater transparency among researchers in reporting the theory of practice underpinning the intervention, delivered content, and the overall aims of the program. Indeed, this review may be more of a critique on the reporting of interventions, rather than on the interventions themselves. For example, most of the MBSR, MBCT, and MBCR interventions grouped as an MIP were classified on the premise of researchers not reporting on the training and core competencies of the therapist delivering the intervention. In addition, great variability was found in the reporting of intervention details among RBIs and DMRs, with many lacking clear descriptions of curricula, theoretical foundations, and key mindfulness-based components such as developing self-regulation, compassion, and equanimity. Future efficacy studies and protocol papers on MBPs for cancer patients should provide more comprehensive details on the intervention and facilitator competencies/training, particularly for novel interventions that are a mix of existing interventions or combinations of traditional MBPs and other therapies (e.g., music therapy, grounding). We refer researchers to the seminal work by Crane et al. (2017) on what defines an MBP for reporting guidance, as well as the work that has been conducted on assessing facilitators of MBPs (Crane et al., 2013). In addition, the integration of the Treatment Fidelity Tool for Mindfulness Based Interventions checklist is also recommended to ensure findings are valid and reliable (Kechter et al., 2019). Doing so will enable future research to systematically evaluate and ascertain the quality of interventions and competencies of facilitators, allowing for higher quality systematic reviews and meta-analyses of MBPs in general.

Third, all intervention types, regardless of MBP/MIP classification, reporting comprehensiveness, and efficacy methodology, demonstrated some promise for improving one or more patient outcome(s). This is in line with previously reported literature (Fan et al., 2023; Fung et al., 2024; Matis et al., 2020) and current recommendations that MBPs be provided to cancer patients for anxiety and depression (Carlson et al., 2023). However, coupled with our findings that patient experiences can vary across intervention types, interventions should be recommended to cancer patients based on treatment goals, patient preferences, and feasibility of time commitments. For example, MBSR, MBCT, and MBCR interventions may be more suited to patients who can accommodate 1.5–2 hr weekly sessions with a facilitator and are able to engage in a more intense intervention, with MBSRs and MBCRs being more appropriate for those who prefer a group setting. Indeed, previous literature has demonstrated that emotional readiness is important to consider when engaging a cancer patient in an MBSR intervention (Bisseling et al., 2017). In contrast, DMRs may be a more feasible option for patients who prefer flexible, self-guided interventions that can be completed at one’s own pace, or in circumstances when access to a facilitator/mindfulness teacher is limited; however, we suggest that some guidance be provided for such interventions. Alternatively, interventions can be staggered, where patients hesitant to learn mindfulness can begin with a DMR intervention and progress to a more traditional MBP such as MBCT, MBSR, or MBCR depending on preference and treatment goals. When making recommendations for MBPs, clinicians should weigh the pros and cons of different intervention types to optimize patient outcomes and satisfaction.

Regarding intervention content and delivery, this review revealed a general trend toward self-guided interventions being the most commonly evaluated MIPs, particularly within the last 5 years. This may reflect a general shift toward a proclivity for mobile health apps (Melhem et al., 2023), or self-guided interventions, completed at one’s own pace (Baker-Glenn et al., 2011; Ugalde et al., 2017). Alternatively, it may be that self-guided interventions are easier to disseminate, as well as collect usage data and treatment compliance, ensuring a more standardized experience for users and a more straightforward evaluation. More importantly, preliminary evidence suggests that individuals who participate in self-guided mindfulness programs can cultivate mindfulness, challenging the common assumption that facilitator engagement is essential. However, it is important to note that these results are preliminary and may not apply to clinical populations, such as cancer patients, who may face greater challenges in engagement, adherence, and long-term effectiveness in self-guided programs. Future research should explore this further. Nonetheless, this begs the question, should existing definitions of what constitutes an MBP be updated to include self-guided interventions that otherwise fulfill most program requirements of an MBP, or should a framework for mindfulness-based self-guided programs (MB-SGP) be developed? Future research should investigate the efficacy and potential benefits of MB-SGPs compared to traditional MBPs, to ensure that the former maintain the integrity and therapeutic value associated with mindfulness practices, which would be beneficial for cancer patients. Despite existing literature demonstrating cancer patients’ preferences for more cancer-content in mind–body therapies, cancer-related content remains an unmet need in many programs (Huberty et al., 2022a, 2022b). Lastly, in examining the methodologies and measures used to evaluate interventions’ efficacy, most studies did not measure change in mindfulness over time, despite the primary aim of MBPs being to cultivate and enhance mindfulness. Only 33% of studies employed a measure of mindfulness, leaving several studies undetermined on whether the intervention was effective in its aims or what the moderators or meditators of successful vs. unsuccessful interventions were. Future MBP efficacy studies with cancer patients are encouraged to include measures of mindfulness, as well as measures of acceptance, awareness, and engagement in mindfulness meditation, as they have been found to be the main active ingredients of these programs (Lindsay et al., 2018; Stein & Witkiewitz, 2020). Additionally, discrepancies were also found in how researchers defined and measured compliance rates/treatment completion, as well as patient satisfaction/experience with the intervention. Overall, treatment compliance rates greatly varied across studies, as some measured time spent on app/number of logins, others defined completion as attending 70% of sessions or more, whereas others simply removed non-treatment completers from their analyses. Regardless of how researchers define compliance, adherence, or treatment completion, future researchers are encouraged to consider these measures when evaluating the feasibility and acceptability of MBPs. Sustained changes in patient outcomes should be given more attention in the literature, as only 25% of articles in this review measured patient outcomes at or beyond 6 months.

Although this review provides clear recommendations for future research in MBPs for cancer patients, results should be interpreted with some caution. The following limitations of this hybrid systematic-narrative review are important to consider when interpreting the findings. Most studies examined were not RCTs—particularly the MBP interventions, which were predominately one-arm pre-post designs. This may have impacted the accuracy of reported outcomes, potentially leading to the overestimating or underestimation of effectiveness in these studies. Additionally, this narrative review combined RCT results with those of pre-post single-arm design studies due to scarcity of research, suggesting that future studies on MBPs and MIPs should prioritize RCTs. This limitation reduces the generalizability of the findings and may confound conclusions about the effectiveness of MBPs and MIPs. Furthermore, comparisons between MBP and MIPs are preliminary, given the disproportionate number of RCTs to one-armed studies, as well as the larger proportion of MBP articles (one-third vs. two-thirds for MIPs). Finally, the heterogeneity of scales used to measure patient outcomes made meaningful comparisons challenging. Future research should evaluate the validity of these scales and recommend which tools are most appropriate for measuring depression, anxiety, distress, sleep, fatigue, and quality of life.