Original Article Cost Effectiveness of Gene Expression Profiling for Early Stage Breast Cancer A Decision-Analytic Model Mo Yang, MS1,2; Suja Rajan, PhD1,2; and Amalia M. Issa, PhD, MPH1,2,3 BACKGROUND: Gene expression profiling (GEP) is being used increasingly for risk stratification to identify women with lymph nodenegative, estrogen receptor-positive, early stage breast cancer who are most likely to benefit from adjuvant chemotherapy. The authors of this report evaluated the cost effectiveness of recurrence score-guided treatment using 2 commercially available GEP tests, Oncotype DX (Genomic Health, Redwood City, Calif) and MammaPrint (Agendia Inc., Irvine, Calif), from a third-party payer’s perspective. METHODS: A 10-year Markov model was developed to compare the costs and quality-adjusted life-years (QALYs) of treatment decisions guided by either Oncotype DX or MammaPrint in a hypothetical cohort of women with early stage, lymph nodenegative, estrogen receptor-positive breast cancer who may experience recurrence. Outcomes included no recurrence, recurrence, and death. The costs considered included gene test costs, the costs of adjuvant chemotherapy and other chemotherapy (including premedication, oncology visits, and monitoring for adverse events), the cost of treating recurrence, costs associated with the treatment of adverse events, and end-of-life care costs. RESULTS: The model demonstrated that the patients who received the Oncotype DX test to guide treatment spent $27,882 (in US dollars) and gained 7.364 QALYs, whereas patients who received the MammaPrint test to guide treatment spent $21,598 and gained 7.461 QALYs. Sensitivity analyses demonstrated that the results were robust to changes in all parameters. CONCLUSIONS: The model suggested that MammaPrint is a more cost-effective GEP test compared with Oncotype DX at a threshold willingness-to-pay of $50,000 per QALY. Because Oncotype DX is the most frequently used GEP in clinical practice in the United States, the authors concluded that the current findings have implications for health policy, particularly C 2012 American Cancer Society. health insurance reimbursement decisions. Cancer 2012;118:5163–70. V KEYWORDS: gene-expression profiling, breast cancer, Markov modeling, cost-effectiveness, health economics. INTRODUCTION Breast cancer is the second most common malignancy and the second most common cause of cancer death for women in the United States. Breast cancer accounts for an estimated 209,060 newly diagnosed cases annually.1 A key challenge for patients with breast cancer and their health care providers while making treatment decisions relates to the decision to use or forego adjuvant chemotherapy.2,3 The argument for the use of adjuvant chemotherapy is the potential to reduce the risk of recurrence and mortality for patients with breast cancer. However, there is variation in the degree of benefit from adjuvant therapy, and the benefit is questionable for patients who have estrogen receptor-positive, or lymph node-negative, or tamoxifen-responsive disease.4-6 Chemotherapy also is expensive for payers and may produce significant toxicities, such as myelosuppression and permanent ovarian failure, which may have a substantial impact on quality of life.4 Several gene expression profiling (GEP) assays are currently on the market for use as genomic diagnostics to provide prognostic or risk information. The potential value of these genomic diagnostics lies in their claims to measure gene expression levels of a patient’s tumor and to produce a ‘‘numerical score’’ depicting risk for disease recurrence. The estimation of disease recurrence helps identify patients who are likely to benefit from chemotherapy and, thus, assists providers in making decisions regarding the administration of chemotherapy. However, these tests differ from one another in several ways, including the presentation of risk recurrence data. To date, Oncotype DX (Genomic Health, Redwood City, Calif), a 21-gene profile assay that uses real-time (RT) polymerase chain reaction (PCR) for expression analysis of paraffin-embedded tissue, remains the most frequently used GEP in clinical practice in the United States. Oncotype DX uses a recurrence score (RS), which places patients in 3 categories: high risk, intermediate risk, and low risk. The putative test objective is to tailor treatment to the individual patient so that Corresponding author: Amalia M. Issa, PhD, MPH, Program in Personalized Medicine and Targeted Therapeutics and Department of Health Policy and Public Health, University of the Sciences, 600 S. 43rd Street, Box 22, Philadelphia, PA 19104; Fax (215) 596-7614; [email protected] 1 Program in Personalized Medicine and Targeted Therapeutics, University of the Sciences, Philadelphia, Pennsylvania; 2Department of Clinical Sciences and Administration, College of Pharmacy, University of Houston, Houston, Texas; 3Department of Health Policy and Public Health, University of the Sciences, Philadelphia, Pennsylvania. DOI: 10.1002/cncr.27443, Received: September 18, 2011; Revised: November 23, 2011; Accepted: December 6, 2011, Published online February 22, 2012 in Wiley Online Library (wileyonlinelibrary.com) Cancer October 15, 2012 5163 Original Article patients with a low risk of recurrence who do not need chemotherapy can avoid it, which will enhance patient quality of life and save money for payers. MammaPrint (Agendia Inc., Irvine, Calif), a 70gene profile microarray assay that was developed and is used more frequently in Europe, reports results in a binary mode: either high risk or low risk for recurrence. MammaPrint uses fresh-frozen tumor tissues, which are available more frequently from procedures done in Europe, whereas Oncotype DX uses tissues preserved in paraffin, a typical procedure in the United States. Two trials with the expressed purpose of examining efficacy and providing level I evidence of Oncotype DX and MammaPrint, the Trial Assigning Individualized Options for Treatment (TAILORx) and the Microarray in Lymph node-Negative Disease may Avoid Chemotherapy (MINDACT) trial, respectively, currently are ongoing.7-9 However, full results from those trials are not yet available, and decisions regarding quality of life and costs need to be made in the interim. Although previous economic analyses have been conducted on GEP assays,10-17 to our knowledge, only 1 study examined MammaPrint,13,17 and we are not aware of any studies that have compared the cost-effectiveness of these 2 commercially available GEPs directly. The use of GEP may have significant effects on patient outcomes, medical services use, and costs. Much of the discussion surrounding health care reform before and after the enactment of the Patient Protection and Affordable Care Act18 is centered on ways to create higher quality, more efficient care and to reduce rising health care expenditures. Thus, assessing the outcomes, use, and costs associated with these genomic diagnostic tests is critical for future clinical decision making. The objective of the current study was to evaluate the cost effectiveness of treatment decisions using Oncotype DX compared with treatment decisions using MammaPrint from a third-party payer’s perspective. MATERIALS AND METHODS Model Description A 10-year Markov model was developed using Tree-Age (TreeAge Software, Williamstown, Mass) to evaluate the costs and quality-adjusted life-years (QALYs) associated with using 2 GEP-guided treatment strategies: Oncotype DX and MammaPrint. Patients were distributed into 3 mutually exclusive health states: no recurrence (diseasefree survival), recurrence, and death. The study was conducted from a third-party payer’s perspective. 5164 The model assumed a hypothetical cohort of 1000 patients with lymph node-negative, estrogen receptorpositive breast cancer and simulated events for receiving either of the 2 GEP tests (Fig. 1). All patients started with a risk classification state based on an assessment by Adjuvant! Online (Adjuvant, Inc., San Antonio, Tex). Subsequently, patients were reclassified into risk categories based on the 2 GEP tests using reclassification probabilities from the literature.15,17,19-22 We compared each of the 2 GEP tests with Adjuvant! Online, because both strategies had been compared previously for analytic validation purposes with Adjuvant! Online in earlier studies.17,19-21 In the first strategy, patients were offered Oncotype DX, and their risk was reclassified using the RS. For the second strategy, patient risk was reclassified according to MammaPrint. We assumed that each patient could only have 1 recurrence. Once a patient enters a health state, the patient will not progress to a better health state. A total simulated time horizon of 10 years was conducted with 1 year considered as a cycle. During each Markov cycle, the patients may remain disease-free or develop recurrence. Once patients develop recurrence, they remain in the recurrence state until they die from breast cancer. Costs and QALYs are discounted at 3% in the base case. Patients may experience no, minor, major, or fatal toxicity from chemotherapy. We also assumed that 90% of patients who were at high risk according to both Adjuvant! Online and Oncotype DX received chemotherapy, whereas 90% of patients who were at low risk according to both Adjuvant! Online and Oncotype DX did not receive chemotherapy. For patients who experienced a conflicting result between Adjuvant! Online and Oncotype DX, 50% of the subpopulation received chemotherapy. The same assumption was applied to MammaPrint. Probability of Risk Classification Data on risk classification using Adjuvant! Online and GEP tests were derived from the literature (Table 1).15,22 For Strategy 1, in total, 668 patients were classified as either low risk or high risk using Adjuvant! Online, and they were reclassified as low risk or high/intermediate risk using the RS. The intermediate-risk group was combined with the high-risk group in the RS category. Of the 354 patients (52.99%) at low risk according to Adjuvant! Online, 216 (61.02%) were reclassified as low risk, and 138 (39%) were reclassified as high risk using the RS. Of the 314 patients (47.01%) at high risk according to Adjuvant! Online, 122 (38.85%) were reclassified as low risk, and 192 (61.15%) were reclassified as high risk using the RS. For Strategy 2, in total, 302 patients were classified as Cancer October 15, 2012 Cost-Effectiveness of GEP Tests/Yang et al Figure 1. The analytical decision model assumed patients with lymph node-negative, estrogen receptive-positive (þ) breast cancer for the Oncotype DX (21-gene signature) and MammaPrint (70-gene signature) gene expression profiling tests, and simulated events for 2 strategies. All patients started in the risk classification state in which they underwent risk assessment by Adjuvant! Online (Adjuvant, Inc., San Antonio, Tex). In the first strategy, patients were offered Oncotype DX, and their risk was reclassified using the recurrence score. For the second strategy, patients’ risk was reclassified according to MammaPrint. either low risk or high risk using Adjuvant! Online, and they were reclassified as low risk or high risk using MammaPrint.18 Of the 80 patients (26.58%) at low risk according to Adjuvant! Online, 52 (65%) were reclassified as low risk, and 28 (35%) were reclassified as high risk using MammaPrint. Of the 222 patients (73.51%) at high risk according to Adjuvant! Online, 59 (26.58%) were reclassified as low risk, and 163 (73.42%) were reclassified as high risk using MammaPrint. Risk of Recurrence and Death Model inputs for transition probabilities based on recurrence rates and death rates for different risk classifications were obtained from the literature (Table 2).10,15-18,23 On the basis of a study by Hornberger et al,10 a 15% relative risk reduction in the recurrence rate because of chemotherapy was applied to patients classified as high risk by both Oncotype DX RS and MammaPrint.10,24,25 A 45% relative risk reduction in the recurrence rate because of chemotherapy was applied to patients classified as low risk Cancer October 15, 2012 by both Oncotype DX RS and MammaPrint.10,24,25 We assumed that the transition probability of death was constant. The probabilities of different toxicities after chemotherapy were obtained from the literature.26 Utility The utility used to adjust survival for quality of life ranges from 0 to 1, with 0 representing death and 1 representing perfect health (Table 2). Utilities for toxicity from chemotherapy, recurrence-free states, and recurrence states were obtained from the peer-reviewed literature, including a systematic review of cost-utility assessment in oncology and a review of health-related quality-of-life estimates.27,29 The QALYs were calculated by the length of time spent in a health state multiplied by the utility of that state. Costs Unit costs were obtained from various sources. All costs are reported in 2009 US dollars. Costs from a different 5165 Original Article Table 1. Risk Reclassification and Recurrence Rates for the Oncotype DX and MammaPrint Gene Expression Profiling Tests Adjuvant! Onlinea Oncotype DXb Comparator Risk Group No. of Patients in Risk Group (%) 10-Year Risk of Recurrence, % Risk Group No. of Patients in Risk Group (%) 10-Year Risk of Recurrence, % References Low 354 (52.99) 8.40 Low 216 (61.02) 5.60 Tsoi 201015; Marchionni 200822 High 314 (47.01) 22.20 Int/high Low Int/high 138 (38.98) 122 (38.85) 192 (61.15) 12.85 8.90 30.71 Comparator Risk Group Adjuvant! Online No. of Patients 10-Year Risk in Risk Group of Recurrence, (%) % Risk Group MammaPrintc No. of Patients 10-Year Risk in Risk Group of Recurrence, (%) % Low 80 (26.49) 8.40 Low 52 (65) 5.60 High 222 (73.51) 22.20 High Low High 28 (35) 59 (26.58) 163 (73.42) 12.85 8.90 30.71 References Tsoi 201015; Buyse 200619; Marchionni 200822 Abbreviations: Int/high, intermediate/high. a Adjuvant! Online; Adjuvant, Inc., San Antonio, Tex. b Oncotype DX; Genomic Health, Redwood City, Calif. c MammaPrint; Agendia Inc., Irvine, Calif. Table 2. Transition Probabilities and Utilities Used in Modeling the 2 Gene Expression Profiling Strategies Variable Base Case Range Tested in Sensitivity Analysis 0.60 0.05 0.005 0.48-0.72 0.04-0.06 0.004-0.006 0.036 0.012 0.036 0.013 0.027-0.045 0.009-0.015 0.027-0.045 0.010-0,016 1.00 0.98 0.75 1.00 0.80 0.70 0 0.75-1.00 0.74-1.00 0.56-0.94 — 0.60-1.00 0.53-0.88 — Reference Transition probability Hillner & Smith 199126 Probability of toxicity Minor Major Fatal Buyse 200619 Death rates: Adjuvant! Online/GEP High/high High/low Low/high Low/low Utility No chemotherapy No recurrence with/without chemotherapy Recurrence with/without chemotherapy No toxicity from chemotherapy Minor toxicity from chemotherapy Major toxicity from chemotherapy Death Assumption Earle 200027 Earle 200027 Assumption Gold 199628 Gold 199628 Assumption Abbreviations: GEP: gene expression profiling. base year were inflated by 3% per year. The cost of Oncotype DX was based on the list price of $3975, whereas the cost of MammaPrint was $4200. Costs of chemotherapy included costs for chemotherapy medications and administration. We assumed a threshold willingness to pay for breast cancer of $50,000, and this was increased to $100,000 for sensi5166 tivity analyses. Costs that were considered in the model are listed in Table 3. Outcomes The model generated estimates of the health care costs and QALYs, incremental cost per QALY gained, and incremental cost-effectiveness ratio (ICER). The ICER Cancer October 15, 2012 Cost-Effectiveness of GEP Tests/Yang et al Table 3. Costs Used in Modeling the 2 Gene Expression Profiling Strategies Variable Base Case, $ Range Tested in Sensitivity Analysis, $ 3975 4200 19,618 2981-4969 3150-5250 14,714-24,523 Reference Slodkowska 200930 GEP tests Oncotype DX MammaPrint Adjuvant chemotherapy Hornberger 200510 Elkin 200439 Other chemotherapy costs Premedication, per cycle Oncology visit, per cycle Monitoring for side-effects, per y Recurrence 15 44 668 10,837 11-18 33-55 501-835 8128-13,546 2709 18,061 45,153 34,778 2032-3386 13,546-22,576 33,865-56,441 26,084-43,473 Hillner & Smith 199126 Hillner & Smith 199126 Treatment of side effects Minor Major Fatal End-of-life Abbreviations: GEP: gene expression profiling. Table 4. Incremental Cost-Effectiveness Ratio Results for the Base Case Diagnostic Strategy Costs, $ Incremental, $ QALYs Incremental QALYs C/E, $/QALYs ICER, $/QALYs MammaPrint Oncotype DX 21,598 27,882 6284 7.461 7.364 0.097 2895 3786 Dominated Abbreviations: C/E, cost-effectiveness; ICER, incremental cost-effectiveness ratio; QALYs, quality-adjusted life-years. estimated the differences in cumulative costs divided by the differences in QALYs between the Oncotype DX and MammaPrint strategies. Sensitivity Analyses One-way sensitivity analyses were performed on assumptions, probabilities, and costs while holding the other variables fixed to assess the robustness of the Markov model. A probabilistic analysis using Monte Carlo simulation was carried out to determine the effect of uncertainty in all variables on the cost-utility ratio for the cohort. We applied the simulation 1000 times to ensure the reliability of the model. To quantify the uncertainty captured by the sensitivity analysis, we used 1000 Monte Carlo simulations to perform t tests and establish whether the costs and effectiveness associated with MammaPrint and Oncotype DX were statistically different from one another. This helped establish the statistical robustness of our sensitivity analysis. RESULTS Base-Case Analysis The model shows that patients for whom Oncotype DX was used to guide treatment spent US $27,882 and gained 7.364 QALYs, whereas patients for whom MammaPrint Cancer October 15, 2012 was used to guide treatment spent US $21,598 and gained 7.461 QALYs (Table 4). The results suggest that MammaPrint is a more cost-effective test than Oncotype DX at a threshold willingness to pay of $50,000 per QALY. Sensitivity Analyses Sensitivity analyses were performed using an incremental cost-effectiveness (ICE) scatter plot between Oncotype DX versus MammaPrint with 1000 Monte Carlo simulation trials using MammaPrint as the reference category (Fig. 2). In this plot, each trial point represents a comparison of the incremental costs and effectiveness of MammaPrint and Oncotype DX using simultaneous and randomly assigned values from the probability, costs and outcome distributions of the base-case parameter estimates. The ICE scatter plot diagram was divided into 4 quadrants. A trial point in Quadrant I indicates that Oncotype DX is more costly and more effective than MammaPrint. A trial point in Quadrant II indicates that Oncotype DX is more costly and less effective than MammaPrint, thereby indicating that MammaPrint the dominant strategy. A trial point in Quadrant III suggests that Oncotype DX is less costly and less effective than MammaPrint. A trial point in Quadrant IV suggests that Oncotype DX is less costly and more effective than 5167 Original Article Figure 2. This is an incremental cost-effectiveness scatter plot of the 2 gene expression profiling tests: Oncotype DX (Genomic Health, Redwood City, Calif) versus MammaPrint (Agendia Inc., Irvine, Calif). QALY indicates quality-adjusted life-year. MammaPrint, thereby indicating that Oncotype DX is the dominant strategy. Figure 2 indicates that 82% of our trial points are in Quadrant II, indicating that MammaPrint is the dominant strategy. T tests for means performed using the 1000 Monte Carlo simulation values provided the following results: 1. Costs of Oncotype DX and MammaPrint are statistically different with P values < .01; the mean cost of Oncotype DX is $27,882 with a standard error of $1455, and the mean cost of Mamma Print is $21,598 with a standard error of $1246. 2. The effectiveness of Oncotype DX and Mamma Print are statistically different with P values < .01; the mean effectiveness of Oncotype DX is 7.36 with a standard error of 0.07, and the mean effectiveness of MammaPrint is 7.46 with a standard error of 0.07. One-way sensitivity analyses also were performed by varying the values of the probabilities, utilities, and costs. MammaPrint was identified as beneficial and cost effective using alternative assumptions, probabilities, and cost variables that were measured in the sensitivity analysis. In the univariate sensitivity analyses, the results were robust to changes in all parameters. DISCUSSION We used a decision-analytic model to estimate the costs, QALYs, and incremental cost-effectiveness of 2 commercially available GEPs: Oncotype DX and MammaPrint, which are used to guide treatment decisions about adju5168 vant chemotherapy in early stage breast cancer. To the best of our knowledge, this study is the first of its kind to compare the cost effectiveness of Oncotype DX directly with that of MammaPrint. In the base-case analysis and in the probabilistic sensitivity analysis of recurrence rates under the 2 testing strategies, the MammaPrint test dominated the Oncotype DX test. Because Oncotype DX is the most frequently used GEP in clinical practice in the United States, our finding has implications for health policy, particularly health insurance reimbursement decisions. It has been estimated that the willingness to pay for better health outcomes in the United States is approximately $50,000 per QALY gained, and it is well known that cancer therapeutics have relatively high ICERs.31-34 Thus, although both Oncotype DX and MammaPrint are costly and have high ICERs, it is reasonable to presume a willingness to pay for testing strategies that are likely to yield reduced expenditures for payers, health systems, patients, and society in the long term. This study has several limitations. Like all decisionanalytic models, our cost-effectiveness analysis relies on key assumptions. The available data for inputs into our model were limited; therefore, we combined the 21-gene signature, RS-guided, high-risk and intermediate-risk groups into 1 group (called high risk). We did not specify recurrence as local or regional recurrence, a secondary primary, or a contralateral breast cancer because of the limited availability of data. We opted to model 1 relapse per patient, which is the common assumption.35-37 Thus, there may be an underestimate of relapse costs if certain patients developed more than 1 relapse (and approximately 30% of patients with breast cancer do develop more than 1 relapse). Finally, our analysis reflects a thirdparty payer perspective from the United States that may not be applicable in other health care systems. In summary, we modeled 2 commercially available GEP tests, Oncotype DX and MammaPrint, both of which are aimed at providing information based on genetic characteristics of breast cancer tumors to aid in guiding treatment decisions about adjuvant therapy. Our analysis suggests that MammaPrint is the more cost-effective (dominant) testing strategy for guiding treatment decisions for adjuvant therapy in early stage breast cancer. Oncotype DX uses an RS that places patients into 3 risk categories: high, intermediate, and low. On the basis of available population-level data to date, patients who receive intermediate risk scores of 11 to 25 have a breast cancer recurrence rate between 7% and 16%. The effects of adjuvant chemotherapy combined with hormone Cancer October 15, 2012 Cost-Effectiveness of GEP Tests/Yang et al therapy in patients who receive an intermediate score (approximately 44% of patients with lymph node-negative, hormone-positive breast cancer) are unknown. Furthermore, oncologists report that an intermediate score is ambiguous for informed decision making.38 Therefore, the use of MammaPrint as a prognostic assessment tool is not only cost effective, it also appears to circumvent the ambiguity in the Oncotype DX RS results. New genomic diagnostics and personalized medicine applications are increasingly entering the market, and this broader availability of diagnostics has major implications for health care delivery. Oncotype DX and MammaPrint are the first of a new wave of technologies designed to provide prognostic information that can directly impact treatment decisions and, as a consequence, use and cost effectiveness in health care delivery systems. Considering the increasing costs of cancer therapeutics and companion diagnostics in oncology, our current study provides a valuable and timely contribution to the literature and to policy makers. Our analysis may assist payers and health care providers in selecting the optimal GEP strategy until further level I evidence is available from the TAILOR-X and MINDACT trials.39 FUNDING SOURCES This work was supported by a grant from InHealth, the Institute for Health Technology Studies (principal investigator: Amalia M. Issa, PhD, MPH). CONFLICT OF INTEREST DISCLOSURES The authors made no disclosures. REFERENCES 1. Jemal A, Siegel R, Xu J, et al. Cancer statistics. CA Cancer J Clin. 2010;60:277-300. 2. National Comprehensive Cancer Network. 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