What determines patient preferences for treating low risk basal cell carcinoma when comparing surgery vs imiquimod? A discrete choice experiment survey from the SINS trial

Surgical excision versus topical 5% 5-fluorouracil and photodynamic therapy in treatment of Bowen's disease: A multicenter randomized controlled trial

BACKGROUND

Randomized controlled trials comparing the effectiveness of 5-fluorouracil cream, methylaminolevulinate photodynamic therapy (MAL-PDT) and surgical excision in patients with Bowen's disease are lacking.

METHODS

In this multicenter noninferiority trial, patients with a histologically proven Bowen's disease of 4-40 mm were randomly assigned to excision with 5 mm margin, 5% 5-fluorouracil cream twice daily for 4 weeks, or 2 sessions of MAL-PDT with 1 week interval. The primary outcome was the proportion of patients with sustained clearance at 12 months after treatment. A noninferiority margin of 22% was used.

RESULTS

Between May 2019 and January 2021, 250 patients were randomized. The proportion of patients with sustained clearance was 97.4% (75/77) after excision, 85.7% (66/77) after 5-fluorouracil, and 82.1% (64/78) after MAL-PDT. Absolute differences were -11.7% (95% CI -18.9 to -4.5; P = .0049) for 5-fluorouracil versus excision and -15.4% (95% CI -23.1 to -7.6; P = .00078) for MAL-PDT versus excision. Both noninvasive treatments significantly more often led to good or excellent cosmetic outcome.

CONCLUSIONS

Based on our predefined noninferiority margin of 22%, 5-fluorourcail is noninferior to excision and associated with better cosmetic outcome. For MAL-PDT noninferiority to excision cannot be concluded. Therefore, 5-fluorouracil should be preferred over excision and MAL-PDT in treatment of Bowen's disease.

Topical Treatments for Basal Cell Carcinoma and Actinic Keratosis in the United States

Skin cancer is an overarching label used to classify a variety of cutaneous malignancies. Surgical excision procedures are the commonly used treatments for these lesions; however, the choice to perform operative intervention may be influenced by other factors. Established research and literature suggest that topical treatments limit the need for surgical intervention and its commonly associated adverse effects, including infection and scarring. In addition, the growing indications for the usage of topical therapies in BCC treatment, as well as their increased availability and therapeutic options, allow for their greater applicability in the dermatology clinic. Certain topical therapies have been highlighted in research, especially those targeting basal cell carcinoma (BCC) and actinic keratosis (AK). There is also a clear correlation between cost and treatment outcomes, considering BCC's ever-growing prevalence and the proportion of excised lesions being reported as malignant. This review will discuss BCC and AK lesion criteria that result in the most successful outcomes using topical treatments, then highlight the various topical treatment options, and finally address their clinical significance moving forward.

Patient Preference for Optical Coherence Tomography versus Punch Biopsy for Diagnosis of Basal Cell Carcinoma: A Labelled Discrete Choice Experiment

Abstract is missing (Short communication)

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.

Willingness to Pay for Surgical Treatments for Basal Cell Carcinoma: A Population-Based Cross-Sectional Study

BACKGROUND

Keratinocyte carcinoma (KC) treatment accounts for approximately $5 billion in spending per year, yet no studies have evaluated the US general public's willingness to pay (WTP) for these procedures.

OBJECTIVE

To determine the monetary value of surgical KC treatments, as perceived by society, as a measure of preference.

PARTICIPANTS, METHODS AND MATERIALS

We performed an internet-based age-, sex-, and race-stratified cross-sectional survey of 425 subjects representative of the US general population. Stated WTP and desirability of electrodesiccation and curettage (EDC), excision, and Mohs micrographic surgery (MMS) for facial and extrafacial basal cell carcinoma (BCC) were assessed. A discrete choice experiment was performed using maximum likelihood estimation, and a secondary analysis was performed to determine the influence of framing MMS as the best treatment option.

RESULTS

A total of 425 subjects finished their questionnaires, yielding a completion rate of 97%. Median (interquartile range) stated WTP for EDC, excision, and MMS were $1,000 (421-2,079), $1,503 (562-3,062), and $3,006 (1,250-5,084), respectively, when MMS was framed in a standard fashion. Stated WTP for MMS increased to $3,989 (2,015-5,801) when it was framed as the best option. For BCC on the back, WTP for MMS dropped by 12%.

CONCLUSION

There is markedly higher societal WTP for MMS on both the face and trunk, regardless of whether MMS is framed as the best option. Gold-standard bias may affect WTP and desirability in medical decision-making under uncertainty, inflating the WTP of options framed as the best while decreasing the desirability of alternatives.

A review of emerging and non-US FDA-approved topical agents for the treatment of basal cell carcinoma

Although surgical therapy continues to be the gold standard for the treatment of basal cell carcinoma given high cure rates and the ability to histologically confirm tumor clearance, there are a number of nonsurgical treatment options that may be considered based on individual tumor characteristics, functional and cosmetic considerations, patient comorbidities and patient preference. Topical 5-fluorouracil 5% cream and imiquimod 5% cream have been US FDA-approved for the treatment of superficial basal cell carcinoma. Additionally, a number of new and emerging topical agents and techniques have been described for the treatment of basal cell carcinoma and will be reviewed herein.

Respondent Understanding in Discrete Choice Experiments: A Scoping Review

Introduction

Despite the recognised importance of participant understanding for valid and reliable discrete choice experiment (DCE) results, there has been limited assessment of whether, and how, people understand DCEs, and how ‘understanding’ is conceptualised in DCEs applied to a health context.

Objectives

Our aim was to identify how participant understanding is conceptualised in the DCE literature in a health context. Our research questions addressed how participant understanding is defined, measured, and used.

Methods

Searches were conducted (June 2019) in the MEDLINE, EMBASE, PsychINFO and Econlit databases, as well as hand searching. Search terms were based on previous DCE systematic reviews, with additional understanding keywords used in a proximity-based search strategy. Eligible studies were peer-reviewed journal articles in the field of health, related to DCE or best-worst scaling type 3 (BWS3) studies, and reporting some consideration or assessment of participant understanding. A descriptive analytical approach was used to chart relevant data from each study, including publication year, country, clinical area, subject group, sample size, study design, numbers of attributes, levels and choice sets, definition of understanding, how understanding was tested, results of the understanding tests, and how the information about understanding was used. Each study was categorised based on how understanding was conceptualised and used within the study.

Results

Of 306 potentially eligible articles identified, 31 were excluded based on titles and abstracts, and 200 were excluded on full-text review, resulting in 75 included studies. Three categories of study were identified: applied DCEs (n = 52), pretesting studies (n = 7) and studies of understanding (n = 16). Typically, understanding was defined in relation to either the choice context, such as attribute terminology, or the concept of choosing. Very few studies considered respondents’ engagement as a component of understanding. Understanding was measured primarily through qualitative pretesting, rationality or validity tests included in the survey, and participant self-report, however reporting and use of the results of these methods was inconsistent.

Conclusions

Those conducting or using health DCEs should carefully select, justify, and report the measurement and potential impact of participant understanding in their specific choice context. There remains scope for research into the different components of participant understanding, particularly related to engagement, the impact of participant understanding on DCE validity and reliability, the best measures of understanding, and methods to maximise participant understanding.

Electronic supplementary material

The online version of this article (10.1007/s40271-020-00467-y) contains supplementary material, which is available to authorized users.

Health-Related Quality of Life and Patient-Reported Outcomes in Radiation Oncology Clinical Trials

OPINION STATEMENT

The importance of assessing health-related quality of life (HRQoL) and patient-reported outcomes (PROs) is now well recognized as an essential measure when evaluating the effectiveness of new cancer therapies. Quality of life measures provide for a multi-dimensional understanding of the impact of cancer treatment on measures ranging from functional, psychological, and social aspects of a patient's health. Patient-reported outcomes provide for an assessment of physical and functional symptoms that are directly elicited from patients. Collection of PROs and HRQoL data has been shown to not only be feasible but also provide for reliable measures that correlate with established outcomes measures better than clinician-scored toxicities. The importance of HRQoL measures has been emphasized by both patients and clinicians, as well as policy makers and regulatory bodies. Given the benefits associated with measuring HRQoL and PROs in oncology clinical trials, it is increasingly important to establish methods to effectively incorporate PROs and HRQoL measures into routine clinical practice.

Patient preferences for reducing bowel adverse events following prostate radiotherapy

BACKGROUND

The Extended Prostate Cancer Index Composite (EPIC) instrument is a commonly used patient reported outcome (PRO) tool in prostate cancer clinical trials. Summary scores for EPIC subscales are calculated by averaging patient scores for attributes (e.g., side effects), implying equal weighting of the attributes in the absence of evidence showing otherwise.

METHODS

We estimated patient preferences for each of the attributes included in the bowel subscale of the EPIC instrument using best-worst (B-W) scaling among a cohort of men with prostate cancer. Patients were presented with multiple tasks in which they were asked to indicate which attribute they would find most and least bothersome at different levels of severity. Analysis utilized both (simple) B-W counts and scores to estimate patient preferences for each attribute as well as attribute levels.

RESULTS

A total of 174 respondents from two institutions participated in the survey. Preference estimates for each of the five attributes included in the EPIC-26 bowel subscale showed wide variation preferences: 'losing control of bowel movements' was found to be the most bothersome attribute, with a B-W score of -0.48, followed by bowel urgency which also had negative B-W score (-0.04). Increased frequency of bowel movements was the least bothersome attribute, with a B-W score of +0.33, followed by bloody stools (+0.12), and pelvic/rectal pain (+0.06). Analysis of preference weights for attribute bother levels showed preference estimates be linear.

CONCLUSIONS

We provide novel evidence on patient preferences for side effect reduction following prostate radiotherapy. Within the bowel sub-scale of the EPIC-26 short form, we found that bowel incontinence was perceived to be the most bothersome treatment effect, while increased bowel frequency was least bothersome to patients.

Intradermal Delivery of an Immunomodulator for Basal Cell Carcinoma; Expanding the Mechanistic Insight into Solid Microneedle-Enhanced Delivery of Hydrophobic Molecules

Basal cell carcinoma (BCC) is the most common cutaneous malignancy in humans. One of the most efficacious drugs used in the management of BCC is the immunomodulator, imiquimod. However, imiquimod has physiochemical properties that limit its permeation to reach deeper, nodular tumor lesions. The use of microneedles may overcome such limitations and promote intradermal drug delivery. The current work evaluates the effectiveness of using an oscillating microneedle device Dermapen either as a pre- or post-treatment with 5% w/w imiquimod cream application to deliver the drug into the dermis. The effectiveness of microneedles to enhance the permeation of imiquimod was evaluated ex vivo using a Franz cell setup. After a 24-h permeation experiment, sequential tape strips and vertical cross-sections of the porcine skin were collected and analyzed using time-of-flight secondary ion mass spectrometry (ToF-SIMS). In addition, respective Franz cell components were analyzed using high-performance liquid chromatography (HPLC). Analysis of porcine skin cross-sections demonstrated limited dermal permeation of 5% w/w imiquimod cream. Similarly, limited dermal permeation was also seen when 5% w/w imiquimod cream was applied to the skin that was pretreated with the Dermapen, this is known as poke-and-patch. In contrast, when the formulation was applied first to the skin prior to Dermapen application, this is known as patch-and-poke, we observed a significant increase in intradermal permeation of imiquimod. Such enhancement occurs immediately upon microneedle application, generating an intradermal depot that persists for up to 24 h. Intradermal colocalization of isostearic acid, an excipient in the cream, with imiquimod within microneedle channels was also demonstrated. However, such enhancement in intradermal delivery of imiquimod was not observed when the patch-and-poke strategy was used with a non-oscillating microneedle applicator, the Dermastamp. The current work highlights that using the patch-and-poke approach with an oscillating microneedle pen may be a viable approach to improve the current treatment in BCC patients who would prefer a less invasive intervention relative to surgery.

Characteristics of Patients Hospitalized for Cutaneous Squamous Cell Carcinoma

BACKGROUND

Knowledge regarding the inpatient burden of cutaneous squamous cell carcinoma (cSCC) is limited.

OBJECTIVE

To provide nationally representative estimates for hospitalization characteristics due to cSCC and determine predictors for increased length of stay (LOS) and cost of care.

METHODS/MATERIALS

A retrospective cohort study of the 2009 to 2015 National Inpatient Sample. Weighted multivariate logistic/linear regression models were created to evaluate sociodemographic factors associated with cSCC hospitalization and to assess characteristics associated with cost of care and LOS.

RESULTS

This study included 15,784 cSCC and 255,244,626 non-SCC inpatients (prevalence = 6.2/100,000 inpatients). On average, cSCC hospitalizations lasted 5.8 days and cost $66,841.00. Cutaneous squamous cell carcinoma most often occurred on the scalp (30.57%), face (21.08%), and lower limb (11.93%). Controlling for all other factors, cSCC inpatients presented to larger/urban/teaching hospitals and were most often older non-Hispanic white women. More chronic conditions/diagnoses/procedures and nonwhite race were associated with greater cost of care and LOS. Cost of care and LOS significantly differed between cSCCs of different anatomical sites. The most common procedures performed were skin grafts (27.96%), excisions (25.83%), and lymph node biopsies (11.39%).

CONCLUSION

This study highlights the substantial burden of inpatient cSCC in the United States. Further research is necessary to prevent cSCC hospitalizations and improve inpatient dermatologic care for cSCC.

A Review on Imiquimod Therapy and Discussion on Optimal Management of Basal Cell Carcinomas

Basal cell carcinoma (BCC) is the most common type of skin cancer with an increasing incidence. However, it is still poorly researched compared to many other human diseases. Today, cutaneous neoplasms are a frequent, major problem faced by medical professionals. BCC tumors can cause extensive cosmetic distress as well as disfigurement to patients especially when on the face. Treatment options include surgery, systemic agents, and topical agents. Over the past few decades more studies have been performed to evaluate the utility of topical imiquimod therapy for treatment of BCC. Imiquimod is a toll-like receptor that modifies the immune response via the up-regulation of cytokines and has the capacity to improve a person's immune response. Multiple clinical studies have demonstrated the ability of topical imiquimod to diminish or even eradicate basal cell carcinoma. Given this variety of treatment options and the need for noninvasive options, this review is focused on summarizing the existing information available on the use of imiquimod for BCC and comparing it to other treatment modalities. While excision is the first line treatment and often has greater success with regards to clearance, imiquimod has been shown to be an efficacious treatment modality for BCC. Imiquimod therapy has been shown to be a less invasive and cheaper option than many other treatment modalities. It may be used as either monotherapy or in combination with other treatments, though occlusion has not been shown to be helpful. Several dosing regimens have been studied in the literature. Dosing should take into account factors such as the type of BCC, location, and physician/patient comfort with the regimen. Variability in response to treatment with imiquimod amongst studies suggests that response to treatment may depend on location of lesion, thus more research must be done in this area.

Factors and situations influencing the value of patient preference studies along the medical product lifecycle: a literature review

Industry, regulators, health technology assessment (HTA) bodies, and payers are exploring the use of patient preferences in their decision-making processes. In general, experience in conducting and assessing patient preference studies is limited. Here, we performed a systematic literature search and review to identify factors and situations influencing the value of patient preference studies, as well as applications throughout the medical product lifecyle. Factors and situations identified in 113 publications related to the organization, design, and conduct of studies, and to communication and use of results. Although current use of patient preferences is limited, we identified possible applications in discovery, clinical development, marketing authorization, HTA, and postmarketing phases.

Conventional and combination topical photodynamic therapy for basal cell carcinoma: systematic review and meta-analysis

BACKGROUND

Topical photodynamic therapy (PDT) is an established treatment option for low-risk basal cell carcinoma (BCC).

OBJECTIVES

To compare efficacy, cosmesis and tolerability of PDT for BCC with alternative treatments.

METHODS

MEDLINE, PubMed, Embase and CENTRAL databases were searched from inception until 1 September 2017. Included studies were randomized controlled trials (RCTs) of PDT for nodular (n) and superficial (s) BCC reporting at least one of the following outcomes: clearance at 3 months and sustained at 1 or 5 years; recurrence at ≥ 1 year; cosmesis; adverse events; tolerability.

RESULTS

From 2331 search results, 15 RCTs (2327 patients; 3509 BCCs) were included. PDT efficacy (5-year sustained clearance) was high but inferior to excisional surgery [nBCC pooled risk ratio (RR) 0·76; 95% confidence interval (CI) 0·63-0·91], and without re-treatment of partially responding lesions, was modestly inferior to imiquimod (sBCC: RR 0·81; 95% CI 0·70-0·95) and similar to fluorouracil (sBCC: RR 0·88; 95% CI 0·75-1·04). Five-year sustained clearance was inferior with conventional vs. fractionated PDT (sBCC: RR 0·76; 95% CI 0·68-0·84). PDT cosmesis was superior to surgery (sBCC: RR 1·68, 95% CI 1·32-2·14; nBCC: RR 1·82, 95% CI 1·19-2·80) and cryosurgery (BCC: RR 3·73, 95% CI 1·96-7·07), and without re-treatment of partially responding lesions was similar to imiquimod (sBCC: RR 1·01, 95% CI 0·85-1·19) and fluorouracil (sBCC: RR 1·04, 95% CI 0·88-1·24). Peak pain was higher but of shorter duration with PDT than topical treatments. Serious adverse reactions were rarer with PDT than imiquimod (sBCC: RR 0·05, 95% CI 0·00-0·84) and fluorouracil (sBCC: RR 0·11, 95% CI 0·01-2·04). Combination PDT regimens demonstrated reduced recurrence and improved cosmesis; however, results from these small studies were often nonsignificant.

CONCLUSIONS

PDT is an effective treatment for low-risk BCC, with excellent cosmesis and safety. Imiquimod has higher efficacy than single-cycle PDT but more adverse effects. Highest efficacy is with excisional surgery. Fractionated and combination PDT options warrant further study.

Five-Year Results of a Randomized Controlled Trial Comparing Effectiveness of Photodynamic Therapy, Topical Imiquimod, and Topical 5-Fluorouracil in Patients with Superficial Basal Cell Carcinoma

For the treatment of superficial basal cell carcinoma, a prospective, noninferiority, randomized controlled multicenter trial with 601 patients showed that 5% imiquimod cream was superior and 5-fluorouracil cream not inferior to methyl aminolevulinate photodynamic therapy (MAL-PDT) at 1 and 3 years after treatment. No definite conclusion could be drawn regarding the superiority of imiquimod over 5-fluorouracil. We now present the 5-year follow-up results according to the intention-to-treat analysis. Five years after treatment, the probability of tumor-free survival was 62.7% for methyl aminolevulinate photodynamic therapy (95% confidence interval [CI] = 55.3-69.2), 80.5% for imiquimod (95% CI = 74.0-85.6), and 70.0% for 5-fluorouracil (95% CI = 62.9-76.0). The hazard ratio for treatment failure of imiquimod and 5-fluorouracil were 0.48 (95% CI = 0.32-0.71, P < 0.001) and 0.74 (95% CI = 0.53-1.05, P = 0.09), respectively, when compared with methyl aminolevulinate photodynamic therapy. Compared with 5-fluorouracil, imiquimod showed a hazard ratio of 0.65 (95% CI 0.43-0.98, P = 0.04). In conclusion, 5 years after treatment, the results of this trial show that 5% imiquimod cream is superior to both methyl aminolevulinate photodynamic therapy and 5-fluorouracil cream in terms of efficacy for superficial basal cell carcinoma. We therefore consider 5% imiquimod cream as the first choice for noninvasive treatment in most primary superficial basal cell carcinomas.

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.

Imiquimod 5% cream for the treatment of large nodular basal cell carcinoma at the medial canthal area

Context (Background):

Imiquimod (IMQ) 5% cream is an immunomodulatory and antitumorigenic agent, which was used as a topical treatment regimen, who had periocular basal cell carcinoma (BCC).

Aim:

This study aims to present three cases with large BCC at the medial canthal area treated with IMQ 5% cream.

Materials and Methods:

IMQ 5% cream was used in three patients with ages 45, 49, and 73 who preferred medical treatment over surgery. Following incisional biopsy IMQ cream was used once a day, 5 times a week and the patients were followed up weekly during 12 week treatment period and monthly after the clearance of the lesion.

Results:

Erythema and erosion on the surface of the lesion, injection of conjunctiva, burning and itching sensation, epiphora and punctate keratitis were seen in all patients during the treatment period. The ophthalmic side effects could be managed by topical lubricating eye drops and the inflammatory reactions resolved within 1 month after cessation of therapy. The patients were followed up for at least 3 years without tumor recurrence and the biopsies taken from the suspected area were found to be tumor free.

Conclusion:

Surgical excision of carcinoma of the eyelid at medial canthal area can be difficult without causing damage to the lacrimal system and reconstruction of the defect may need grafts or flaps. IMQ may provide an alternative therapy to surgery in certain cases.

Treatment of Low-Risk Basal Cell Carcinoma

With the continuously rising incidence and changing populations of patients with basal cell carcinoma, evidence about the different treatment modalities is mandatory. Randomized clinical trials, such as the surgery versus imiquimod for nodular superficial basal cell carcinoma trial, can provide this evidence. Patients can then be informed about all aspects of alternative treatment options so that conscious, shared decisions can be made.

Sample Size Requirements for Discrete-Choice Experiments in Healthcare: a Practical Guide

Discrete-choice experiments (DCEs) have become a commonly used instrument in health economics and patient-preference analysis, addressing a wide range of policy questions. An important question when setting up a DCE is the size of the sample needed to answer the research question of interest. Although theory exists as to the calculation of sample size requirements for stated choice data, it does not address the issue of minimum sample size requirements in terms of the statistical power of hypothesis tests on the estimated coefficients. The purpose of this paper is threefold: (1) to provide insight into whether and how researchers have dealt with sample size calculations for healthcare-related DCE studies; (2) to introduce and explain the required sample size for parameter estimates in DCEs; and (3) to provide a step-by-step guide for the calculation of the minimum sample size requirements for DCEs in health care.

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.