Patient preferences for reducing toxicities of treatments for gastrointestinal stromal tumor (GIST)

Patient Preferences in Targeted Pharmacotherapy for Cancers: A Systematic Review of Discrete Choice Experiments

BACKGROUND

Targeted pharmacotherapy has been increasingly applied in cancer treatment due to its breakthroughs. However, the unmet needs of cancer patients are still significant, highlighting the urgency to investigate patient preferences. It is unclear how patients deliberate their choices between different aspects of targeted therapy, including cost, efficacy, and adverse events. Since discrete choice experiments (DCEs) have been widely applied to patient preference elicitation, we reviewed DCEs on targeted therapy for different cancers. We also synthesized evidence on the factors influencing patients' choices and their willingness-to-pay (WTP) for survival when treated by targeted therapy.

METHODS

We searched databases, including PubMed, EMBASE and MEDLINE, up to August 16, 2022, supplemented by a reference screening. The attributes from the selected studies were categorized into three groups: outcomes, costs, and process. We also calculated the relative importance of attributes and WTP for survival whenever possible. The purpose, respondents, explanation, findings, significance (PREFS) checklist was used to evaluate the quality of the included DCE studies.

RESULTS

The review identified 34 eligible studies from 13 countries covering 14 cancers, such as breast, ovarian, kidney, prostate, and skin cancers. It also reveals a rising trend of DCEs on this topic, as most studies were published after 2018. We found that patients placed higher weights on the outcome (e.g., overall survival) and cost attributes than on process attributes. On average, patients were willing to pay $561 (95% confidence interval [CI]: $415-$758) and $716 (95% CI $524-$958) out-of-pocket for a 1-month increase in progression-free survival and overall survival, respectively. PREFS scores of the 34 studies ranged from 2 to 4, with a mean of 3.38 (SD: 0.65), suggesting a reasonable quality based on the checklist. However, most studies (n = 32, 94%) did not assess the impact of non-responses on the results.

CONCLUSIONS

This is the first systematic review focusing on patient preferences for targeted cancer therapy. We showcased novel approaches for evidence synthesis of DCE results, especially the attribute relative importance and WTP. The results may inform stakeholders about patient preferences toward targeted therapy and their WTP estimates. More studies with improved study design and quality are warranted to generate more robust evidence to assist decision making.

Patient Medication Preferences for Managing Dry Eye Disease: The Importance of Medication Side Effects

OBJECTIVES

The side effects of dry eye medications can lead to medication non-adherence and, eventually, to poor outcomes. This study aimed to quantify to what extent the side effects of dry eye disease (DED) medications (burning/stinging sensation and blurring) are important to patients compared to medication benefits or costs.

METHODS

Patients diagnosed with DED were recruited at a referral eye center in Singapore (n = 139). This study utilized a Discrete Choice Experiment where patients were presented with 10 choice tasks where they were asked to choose between their current medication (or no medication), and two hypothetical medications that varied based on five attributes: duration of burning/stinging, duration of blurring, time to medication effectiveness, medication frequency, and out-of-pocket cost. The main outcomes were relative attribute importance and predicted uptake.

RESULTS

Latent class logistic regressions found two groups with distinct preferences. For both classes, duration of burning/stinging (Class 1 = 23%, Class 2 = 29%) and cost (Class 1 = 24%, Class 2 = 27%) were the most important attributes while duration of blurring (Class 1 = 15%, Class 2 = 9%) was the least important. The predicted uptake of a medication increased 18 percentage-points when burning/stinging duration decreased from 2 h to a few minutes. The predicted uptake for new medications was lowest for those on medication with well-controlled symptoms and highest for those who were not on medication and could not control their symptoms effectively.

CONCLUSION

This study showed that duration of burning/stinging was an important factor when choosing medications. Incorporating patient preferences in medication decisions can potentially improve patient acceptance of a treatment regimen.

Primary Localized Gastrointestinal Stromal Tumors: Medication Adherence and Prognosis According to Gender

OBJECTIVE

Gender is associated with medication adherence for imatinib, but whether it is related to the prognosis of primary localized gastrointestinal stromal tumors (GISTs) is unclear. The goal of this study was to clarify the relationship between gender and prognosis in GIST patients, with differences in medication adherence considered.

METHODS

The data of 320 GIST patients were retrospectively collected from the First Affiliated Hospital of Chongqing Medical University. Survival analysis was performed using the Kaplan-Meier method (Log rank test) and the risk factors of recurrence were determined using Cox multivariate analysis. Medication adherence-stratified analyses were performed to control for confounding factors.

RESULTS

Kaplan-Meier analysis revealed that among patients who received postoperative adjuvant imatinib therapy, men had a higher recurrence rate than women (P<0.01). Pearson's chi-square test revealed better medication adherence in women than in men (P<0.01). Cox regression analysis revealed that gender was not an independent risk factor for recurrence-free survival (RFS; P=0.25), but medication adherence was (P<0.01). Among GIST patients with a medication possession ratio (MPR) of less than 90%, 62.86% of male patients took imatinib irregularly or not at all due to limited understanding of the disease, whereas 55.74% of female patients' took imatinib irregularly because they could not tolerate adverse drug reactions.

CONCLUSION

Adherence was poorer in male than in female patients, which might explain the worse prognoses of the former among patients who received adjuvant treatment with imatinib. The gender difference in the degree of adherence should be considered in postoperative pharmacotherapy for patients with primary localized GISTs.

Patient Preferences for Outcomes Following DCIS Management Strategies: A Discrete Choice Experiment

PURPOSE

Ductal carcinoma in situ (DCIS), a nonobligate precursor of breast cancer, is often aggressively managed with multimodal therapy. However, there is limited research on patients' preferences for trade-offs among treatment-related outcomes such as breast appearance, side effects, and future cancer risk. We sought to investigate whether women consider treatment features aside from cancer risk when making treatment choices for ductal carcinoma in situ and if so, to what degree other features influence these decisions.

METHODS

A discrete choice experiment was administered to participants in a comprehensive cancer screening mammography clinic. The experimental design was used to generate constructed health profiles resulting from different management strategies. Health profiles were defined by breast appearance, severity of infection within the first year, chronic pain, hot flashes, and risk of developing or dying from breast cancer within 10 years.

RESULTS

One hundred ninety-four women without a personal history of breast cancer completed the choice task. Across 10 choice questions, 29% always selected the health profile with a lower risk of invasive breast cancer (ie, dominated on cancer risk), regardless of the effects of treatment. For nonrisk dominators, breast cancer risk remained the most important factor but was closely followed by chronic pain (24% [95% CI, 20 to 28]) and infection (22% [95% CI, 18 to 25]). Depending on treatment outcomes, the tolerable increase in breast cancer risk was as high as 3.4%.

CONCLUSION

Most women were willing to make some trade-offs between invasive cancer risk and treatment-related outcomes. Our findings highlight the importance of shared decision-making weighing risks and benefits between patient and provider management of low-risk disease.

A Systematic Review of Discrete Choice Experiments in Oncology Treatments

BACKGROUND

As the number and type of cancer treatments available rises and patients live with the consequences of their disease and treatments for longer, understanding preferences for cancer care can help inform decisions about optimal treatment development, access, and care provision. Discrete choice experiments (DCEs) are commonly used as a tool to elicit stakeholder preferences; however, their implementation in oncology may be challenging if burdensome trade-offs (e.g. length of life versus quality of life) are involved and/or target populations are small.

OBJECTIVES

The aim of this review was to characterise DCEs relating to cancer treatments that were conducted between 1990 and March 2020.

DATA SOURCES

EMBASE, MEDLINE, and the Cochrane Database of Systematic Reviews were searched for relevant studies.

STUDY ELIGIBILITY CRITERIA

Studies were included if they implemented a DCE and reported outcomes of interest (i.e. quantitative outputs on participants' preferences for cancer treatments), but were excluded if they were not focused on pharmacological, radiological or surgical treatments (e.g. cancer screening or counselling services), were non-English, or were a secondary analysis of an included study.

ANALYSIS METHODS

Analysis followed a narrative synthesis, and quantitative data were summarised using descriptive statistics, including rankings of attribute importance.

RESULT

Seventy-nine studies were included in the review. The number of published DCEs relating to oncology grew over the review period. Studies were conducted in a range of indications (n = 19), most commonly breast (n =10, 13%) and prostate (n = 9, 11%) cancer, and most studies elicited preferences of patients (n = 59, 75%). Across reviewed studies, survival attributes were commonly ranked as most important, with overall survival (OS) and progression-free survival (PFS) ranked most important in 58% and 28% of models, respectively. Preferences varied between stakeholder groups, with patients and clinicians placing greater importance on survival outcomes, and general population samples valuing health-related quality of life (HRQoL). Despite the emphasis of guidelines on the importance of using qualitative research to inform attribute selection and DCE designs, reporting on instrument development was mixed.

LIMITATIONS

No formal assessment of bias was conducted, with the scope of the paper instead providing a descriptive characterisation. The review only included DCEs relating to cancer treatments, and no insight is provided into other health technologies such as cancer screening. Only DCEs were included.

CONCLUSIONS AND IMPLICATIONS

Although there was variation in attribute importance between responder types, survival attributes were consistently ranked as important by both patients and clinicians. Observed challenges included the risk of attribute dominance for survival outcomes, limited sample sizes in some indications, and a lack of reporting about instrument development processes.

PROTOCOL REGISTRATION

PROSPERO 2020 CRD42020184232.

Mutational Testing in Gastrointestinal Stromal Tumor

Targeted treatment has become a major modality in cancer management. Such cancer drugs are generally designed to treat tumors with certain genetic/genomic makeups. Mutational testing prior to prescribing targeted therapy is crucial in identifying who can receive clinical benefit from specific cancer drugs. Over the last two decades, gastrointestinal stromal tumors (GISTs) have evolved from histogenetically obscure to being identified as distinct gastrointestinal mesenchymal tumors with well-defined clinical and molecular characteristics, for which multiple lines of targeted therapies are available. Although the National Comprehensive Cancer Network (NCCN) strongly recommends mutational testing for optimal management of GIST, many GIST patients still have neither a mutation test performed or any mutation-guided cancer management. Here, we review the mutation-guided landscape of GIST, mutational testing methods, and the recent development of new therapies targeting GIST with specific mutations.

Patients' Preferences for Outcome, Process and Cost Attributes in Cancer Treatment: A Systematic Review of Discrete Choice Experiments

INTRODUCTION

As several studies have been conducted to elicit patients' preferences for cancer treatment, it is important to provide an overview and synthesis of these studies. This study aimed to systematically review discrete choice experiments (DCEs) about patients' preferences for cancer treatment and assessed the relative importance of outcome, process and cost attributes.

METHODS

A systematic literature review was conducted using PubMed and EMBASE to identify all DCEs investigating patients' preferences for cancer treatment between January 2010 and April 2016. Data were extracted using a predefined extraction sheet, and a reporting quality assessment was applied to all studies. Attributes were classified into outcome, process and cost attributes, and their relative importance was assessed.

RESULTS

A total of 28 DCEs were identified. More than half of the studies (56%) received an aggregate score lower than 4 on the PREFS (Purpose, Respondents, Explanation, Findings, Significance) 5-point scale. Most attributes were related to outcome (70%), followed by process (25%) and cost (5%). Outcome attributes were most often significant (81%), followed by process (73%) and cost (67%). The relative importance of outcome attributes was ranked highest in 82% of the cases where it was included, followed by cost (43%) and process (12%).

CONCLUSION

This systematic review suggests that attributes related to cancer treatment outcomes are the most important for patients. Process and cost attributes were less often included in studies but were still (but less) important to patients in most studies. Clinicians and decision makers should be aware that attribute importance might be influenced by level selection for that attribute.

Emerging Opportunities for Target Discovery in Rare Cancers

Rare cancers pose unique challenges to research due to their low incidence. Barriers include a scarcity of tissue and experimental models to enable basic research and insufficient patient accrual for clinical studies. Consequently, an understanding of the genetic and cellular features of many rare cancer types and their associated vulnerabilities has been lacking. However, new opportunities are emerging to facilitate discovery of therapeutic targets in rare cancers. Online platforms are allowing patients with rare cancers to organize on an unprecedented scale, tumor genome sequencing is now routinely performed in research and clinical settings, and the efficiency of patient-derived model generation has improved. New CRISPR/Cas9 and small-molecule libraries permit cancer dependency discovery in a rapid and systematic fashion. In parallel, large-scale studies of common cancers now provide reference datasets to help interpret rare cancer profiling data. Together, these advances motivate consideration of new research frameworks to accelerate rare cancer target discovery.

Understanding Patient Preferences in Medication Nonadherence: A Review of Stated Preference Data

Nonadherence is a global problem undermining the cost-effectiveness of evidence-based medications. Aligning treatment choices with patient preferences may promote adherent behaviour: eliciting patient treatment preferences may help resolve the problem of nonadherence. As there is no reliable measure of nonadherent behaviour that can be used to derive preferences, stated-preference techniques offer a robust alternative. To understand patient preferences in medication nonadherence, we systematically appraised full-text English studies (from database inception to 24 February 2014) involving participants evaluating hypothetical scenarios to elicit preferences as an explicit means to understand medication nonadherence. Study characteristics (e.g. setting, disease, stated-preference method), attribute type and influence on choice were extracted. Seventeen full-text articles (4,456 patients) were included in the review, which reports stated-preference elicitation studies across a wide range of chronic and acute conditions. All studies were conducted in high-income settings. The influence of drug-related factors was predominant in patients' preferences for treatment. Patients preferred efficacious over safe medications except when considering the duration of therapy, but dosing and cost appeared more important when contemplating adherence. Patient characteristics, particularly medication experience, significantly influenced preferences. A disparity between stated preferences for treatment and adherence was reported. When using stated-preference techniques to understand nonadherence, this manuscript highlights that there is much room for methodological development. Studies outside of high-income settings are needed, particularly in relation to chronic diseases, for which nonadherence poses a substantial economic burden to health systems and patients. To inform the problem of sustaining adherence, prospective research is needed to understand how preferences change with time. The usefulness of stated-preference techniques to inform policy and practice requires a better understanding of how stated preferences relate to actual adherence behaviour.

Treatment preference, adherence and outcomes in patients with cancer: literature review and development of a theoretical model

OBJECTIVE

A patient's preference may guide their behavior and influence their willingness to take medication or undergo treatment affecting outcomes, such as health-related quality of life, or survival. The importance of understanding patient preferences within oncology is unclear and few adherence studies exist compared with other therapeutic areas.

RESEARCH DESIGN AND METHODS

This study was designed to review the literature regarding patient preferences, adherence and their link to outcomes specifically in the oncology setting and to propose a theoretical model. An in-depth review was conducted, using Embase, MEDLINE and Cochrane Library databases to search for published data examining patient preference, adherence and oncology-specific outcomes, from 1982-2012. Articles were reviewed independently by two authors and rated for relevance and quality. Information from high-quality articles and discussion with oncology and patient preference experts were used to identify associations between important individual concepts as a basis for a theoretical model.

RESULTS

In total, 1362 abstracts were identified. After removal of duplicates and initial review, 1269 were excluded and 93 reviewed in detail. Of these publications, 18 were deemed 'high-quality' and used to develop the final model. Variables associated with patient preference, adherence and outcome were identified. External variables included communication, treatment and mode of administration; patient beliefs and values were identified as cognitive variables; and adherence was attributed as a behavioral variable. Relationships between patient preference, adherence and clinical outcomes were established. Adverse events had a strong relationship with adherence; patient beliefs and values were identified as having a moderating effect on adherence. Adherence behavior had a direct relationship to outcomes.

CONCLUSIONS

Improving our understanding of patient preference may improve clinical outcomes in oncology patients. Although the proposed theoretical model is limited, it provides a basis to develop testable hypotheses for the relationships between patient preference, adherence and outcomes specific to oncology.

Discrete choice experiments in health economics: a review of the literature

BACKGROUND

Discrete choice experiments (DCEs) are increasingly used in health economics to address a wide range of health policy-related concerns.

OBJECTIVE

Broadly adopting the methodology of an earlier systematic review of health-related DCEs, which covered the period 2001-2008, we report whether earlier trends continued during 2009-2012.

METHODS

This paper systematically reviews health-related DCEs published between 2009 and 2012, using the same database as the earlier published review (PubMed) to obtain citations, and the same range of search terms.

RESULTS

A total of 179 health-related DCEs for 2009-2012 met the inclusion criteria for the review. We found a continuing trend towards conducting DCEs across a broader range of countries. However, the trend towards including fewer attributes was reversed, whilst the trend towards interview-based DCEs reversed because of increased computer administration. The trend towards using more flexible econometric models, including mixed logit and latent class, has also continued. Reporting of monetary values has fallen compared with earlier periods, but the proportion of studies estimating trade-offs between health outcomes and experience factors, or valuing outcomes in terms of utility scores, has increased, although use of odds ratios and probabilities has declined. The reassuring trend towards the use of more flexible and appropriate DCE designs and econometric methods has been reinforced by the increased use of qualitative methods to inform DCE processes and results. However, qualitative research methods are being used less often to inform attribute selection, which may make DCEs more susceptible to omitted variable bias if the decision framework is not known prior to the research project.

CONCLUSIONS

The use of DCEs in healthcare continues to grow dramatically, as does the scope of applications across an expanding range of countries. There is increasing evidence that more sophisticated approaches to DCE design and analytical techniques are improving the quality of final outputs. That said, recent evidence that the use of qualitative methods to inform attribute selection has declined is of concern.

Adherence to imatinib therapy in patients with gastrointestinal stromal tumors

Imatinib mesylate, an oral tyrosine kinase inhibitor, is indicated for first-line treatment of patients with unresectable and/or metastatic gastrointestinal stromal tumors (GIST). Imatinib also is approved as adjuvant therapy for patients following resection of primary GIST. Despite the efficacy of imatinib for the treatment of patients with GIST, adherence to treatment can prove difficult. Clinical studies have identified a number of factors that have a significant association with non-adherence to therapy, including age >51years, female sex, a high number of concomitant medications, and complications with patients' therapy or the disease itself. Moreover, treatment-related adverse events and increased healthcare costs have been shown to have an impact on patients' adherence to therapy. A study of perceptions of adherence to therapy found discrepancies between actual and perceived adherence rates; both patients and physicians overestimate adherence to treatment. Non-adherence to treatment is not exclusive to oncology, and occurs in other disease areas, particularly with chronic conditions. Evidence from other disease areas suggests that routine assessment of adherence and the implementation of adherence programs can lead to improvements in health status and reduced healthcare costs. Improving patient adherence to imatinib treatment for patients with unresectable/metastatic GIST is particularly important, because non-adherence has a significant impact on clinical outcomes and healthcare costs. Therefore, the effective management of treatment-related adverse events along with patient education may be important in keeping patients compliant with continuous therapy.

Adherence to targeted oral anticancer medications

The use of targeted oral anticancer medications (OAMs) is becoming increasingly prevalent in cancer care. Approximately 25-30% of the oncology drug pipeline involves oral agents and there are now over 50 OAMs approved by the Food and Drug Administration. This change represents a major shift in management of patients with cancer from directly observed, intermittent intravenous therapy to self-administered, oral chronic therapy. The increased prevalence of OAMs raises the issue of adherence in oncology, including understanding the challenges of adherence to OAMs. This review focuses on studies of adherence for patients taking molecularly targeted OAMs for breast cancer, chronic myelogenous leukemia (CML), gastrointestinal stromal tumors (GIST), non-small cell lung cancer (NSCLC), and renal cell carcinoma (RCC). We then discuss barriers to adherence and studies performed to date testing interventions for improving adherence. Finally, we discuss future areas of investigation needed to define and improve adherence to OAMs in targeted therapy for cancer.

Effect of pill burden on dosing preferences, willingness to pay, and likely adherence among patients with type 2 diabetes

PURPOSE

To quantify willingness-to-pay (WTP) for reducing pill burden and dosing frequency among patients with type 2 diabetes mellitus (T2DM), and to examine the effect of dosing frequency and pill burden on likely medication adherence.

PATIENTS AND METHODS

Participants were US adults with T2DM on oral antihyperglycemic therapy. Each patient completed an online discrete-choice experiment (DCE) with eight choice questions, each including a pair of hypothetical medication profiles. Each profile was defined by reduction in average glucose (AG), daily dosing, chance of mild-to-moderate stomach problems, frequency of hypoglycemia, weight change, incremental risk of congestive heart failure (CHF), and cost. Patients were asked to rate their likely adherence to the profiles presented in each question. Choice questions were based on a predetermined experimental design. Choice data were analyzed using random-parameters logit. Likely treatment adherence was analyzed using a Heckman two-stage model.

RESULTS

Of the 1,114 patients who completed the survey, 90 had lower dosing burden (<5 pills/day taken once/day or as needed) for all medications, and 1,024 had higher dosing burden (≥5 pills/day or more than once/day). Reduction in AG was valued most highly by patients. Hypoglycemia, chance of mild-to-moderate stomach problems, weight change, incremental risk of CHF, and daily dosing were less valued. Patients with higher current dosing burden had lower WTP for more convenient dosing schedules than patients with lower current dosing burden. Changes in dosing and cost impacted likely adherence. The magnitude of the impact of dosing on likely adherence was higher for patients with lower current dosing burden than for patients with higher current dosing burden.

CONCLUSION

Patients with T2DM were willing to pay for improvements in efficacy, side effects, and dosing. Patients' WTP for more convenient dosing depended on current dosing burden, as did the effect of these attributes on likely adherence.

Digestive tract hemorrhage due to complications with gastrointestinal stromal tumor treated with sunitinib: A case report

Gastrointestinal stromal tumors (GISTs) are rare, and account for 1% of all gastrointestinal neoplasms. GISTs are the most frequent mesenchymal tumors of the gastrointestinal tract. However, the clinical and pathological characteristics of these neoplasms are not adequately understood. The best treatment approach for GISTs remains unclear. In the present study, we report a case of a GIST originating from the stomach. A digestive tract hemorrhage occurred as a complication of sunitinib treatment. This is the first report of a digestive tract hemorrhage due to sunitinib treatment.