Willingness-to-pay for cancer treatment and outcome: a systematic review.

BACKGROUND: Understanding patient preferences in cancer management is essential for shared decision-making. Patient or societal willingness-to-pay (WTP) for desired outcomes in cancer management represents their preferences and values of these outcomes. OBJECTIVE: The aim of this systematic review is to critically evaluate how current literature has addressed WTP in relation to cancer treatment and achievement of outcomes. METHODS: Seven databases were searched from inception until 2 March 2021 to include studies with primary data of WTP values for cancer treatments or achievement of outcomes that were elicited using stated preference methods. RESULTS: Fifty-four studies were included in this review. All studies were published after year 2000 and more than 90% of the studies were conducted in high-income countries. Sample size of the studies ranged from 35 to 2040, with patient being the most studied population. There was a near even distribution between studies using contingent valuation and discrete choice experiment. Based on the included studies, the highest WTP values were for a quality-adjusted life year (QALY) ($11,498-$589,822), followed by 1-year survival ($3-$198,576), quality of life (QoL) improvement ($5531-$139,499), and pain reduction ($79-$94,662). Current empirical evidence suggested that improvement in QoL and pain reduction had comparable weights to survival in cancer management. CONCLUSION: This systematic review provides a summary on stated preference studies that elicited patient preferences via WTP and summarised their respective values. Respondents in this review had comparable WTP for 1-year survival and QoL, suggesting that improvement in QoL should be emphasised together with survival in cancer management.

Cost-effectiveness analysis of olanzapine-containing antiemetic therapy for managing highly emetogenic chemotherapy in Southeast Asia: a multinational study.

PURPOSE: Recent studies suggested that olanzapine, together with dexamethasone and serotonin-3 receptor antagonist (5HT3RA), is effective in preventing chemotherapy-induced nausea and vomiting (CINV) following highly emetogenic chemotherapy (HEC). This regimen is particularly useful in Southeast Asia (SEA) countries where resources are limited. We aimed to evaluate the cost-effectiveness of incorporating olanzapine into standard antiemetic regimens for the prevention of CINV in patients receiving HEC among SEA countries. METHODS: Using a decision tree model, clinical and economic outcomes associated with olanzapine-containing regimen and standard antiemetic regimen (doublet antiemetic regimen: dexamethasone+first generation 5HT3RA) in most SEA countries except in Singapore (triplet antiemetic regimen: dexamethasone+first generation 5HT3RA + aprepitant) for CINV prevention following HEC were evaluated. This analysis was performed in Thailand, Malaysia, Indonesia, and Singapore, using societal perspective method with 5-day time horizon. Input parameters were derived from literature, network meta-analysis, government documents, and hospital databases. Outcomes were incremental cost-effectiveness ratio (ICER) in USD/quality-adjusted life year (QALY) gained. A series of sensitivity analyses including probabilistic sensitivity analysis were also performed. RESULTS: Compared to doublet antiemetic regimen, addition of olanzapine resulted in incremental QALY of 0.0022-0.0026 with cost saving of USD 2.98, USD 27.71, and USD 52.20 in Thailand, Malaysia, and Indonesia, respectively. Compared to triplet antiemetic regimen, switching aprepitant to olanzapine yields additional 0.0005 QALY with cost saving of USD 60.91 in Singapore. The probability of being cost-effective at a cost-effectiveness threshold of 1 GDP/capita varies from 14.7 to 85.2% across countries. CONCLUSION: The use of olanzapine as part of standard antiemetic regimen is cost-effective for the prevention of CINV in patients receiving HEC in multiple SEA countries.

Cost-effectiveness analysis of HLA-B*58: 01 genetic testing before initiation of allopurinol therapy to prevent allopurinol-induced Stevens-Johnson syndrome/toxic epidermal necrolysis in a Malaysian population.

OBJECTIVE: Studies found a strong association between allopurinol-induced Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) and the HLA-B*58:01 allele. HLA-B*58:01 screening-guided therapy may mitigate the risk of allopurinol-induced SJS/TEN. This study aimed to evaluate the cost-effectiveness of HLA-B*58:01 screening before allopurinol therapy initiation compared with the current practice of no screening for Malaysian patients with chronic gout in whom a hypouricemic agent is indicated. METHODS: This cost-effectiveness analysis adopted a societal perspective with a lifetime horizon. A decision tree model coupled with Markov models were developed to estimate the costs and outcomes, represented by quality-adjusted life years (QALYs) gained, of three treatment strategies: (a) current practice (allopurinol initiation without HLA-B*58:01 screening); (b) HLA-B*58:01 screening before allopurinol initiation; and (c) alternative treatment (probenecid) without HLA-B*58:01 screening. The model was populated with data from literature review, meta-analysis, and published government documents. Cost values were adjusted for the year 2016, with costs and health outcomes discounted at 3% per annum. A series of sensitivity analysis including probabilistic sensitivity analysis were carried out to determine the robustness of the findings. RESULTS: Both HLA-B*58:01 screening and probenecid prescribing were dominated by current practice. Compared with current practice, HLA-B*58:01 screening resulted in 0.252 QALYs loss per patient at an additional cost of USD 322, whereas probenecid prescribing resulted in 1.928 QALYs loss per patient at an additional cost of USD 2203. One SJS/TEN case would be avoided for every 556 patients screened. At the cost-effectiveness threshold of USD 8695 per QALY, the probability of current practice being the best choice is 99.9%, in contrast with 0.1 and 0% in HLA-B*58:01 screening and probenecid prescribing, respectively. This is because of the low incidence of allopurinol-induced SJS/TEN in Malaysia and the lower efficacy of probenecid compared with allopurinol in gout control. CONCLUSION: This analysis showed that HLA-B*58:01 genetic testing before allopurinol initiation is unlikely to be a cost-effective intervention in Malaysia.