In the real world, as opposed to the controlled environment of clinical trials, use of the Oncotype DX (Genomic Health) test may not be as cost-effective as was thought. The gene expression profile (GEP) test is used in patients with early breast cancer to help make decisions about further treatment, in particular whether chemotherapy can be avoided.
A new study, which looked at use in a community "real-world setting," found that the likely cost-effectiveness ratio for Oncotype DX testing was higher than the ratios for the most commonly accepted diagnostic and preventive interventions.
The study was published January 8 in the Journal of Clinical Oncology.
Under ideal conditions, such as clinical trial settings, this test has been found to be cost-effective, but when it is used in a less ideal, real-world setting, the cost-effectiveness is different, explained senior author, Jeanne S. Mandelblatt, MD, MPH, professor in the departments of oncology and medicine at Georgetown University School of Medicine and a member of Georgetown Lombardi Comprehensive Cancer Center, Washington, DC.
"The point of our study was that it is important to understand the actual use of new technology, and if it's going to have the intended effectiveness," Dr Mandelblatt told Medscape Medical News.
"When analyzing data about a treatment in a clinical trial, you get a particular magnitude that is sufficiently significant without undue toxicity, and it receives FDA [US Food and Drug Administration] approval," she said. "But then when it's used in the general population, you don't see the same effect. This is because it may be used differently than in the trial, or the patients in the trial were healthier and more select than what is seen in general community practice."
"This is an issue," she noted. "Clinical trials are the best source of evidence that we have, but then the next step — and a really critical one — is to assess the true population impact."
Dr Mandelblatt explained that the actual impact seen in their trial was different than in past analyses. "It's not that they were wrong and we are right," she emphasized. "These trials showed the maximum possible impact at the most reasonable cost, but the actual implementation in the real world was different than what was assessed in those analyses. They were correct for what their purpose was, but then you need to follow through and see how it is actually implemented to understand the real cost-effectiveness."
Variance in Testing Patterns
GEP testing is now considered standard of care for supporting treatment decision making for patients with early-stage, node-negative, estrogen receptor–positive, human epidermal growth factor receptor 2–negative cancers. Previous analyses of GEP have assessed hypothetical cohorts under ideal conditions and concluded that testing had low costs relative to its benefits.
For their study, Dr Mandelblatt and colleagues developed a model that would reflect actual use in the community.
Their simulation model compared 25-year incremental costs and quality-adjusted life-years (QALYs) for Oncotype DX use in the community from 2005 to 2012 with costs and QALYs of usual care in the time period before testing (2000 to 2004).
They ran 100 million simulations to reduce Monte Carlo error when estimating costs and effects, using national data, published research, and electronic records from Kaiser Permanente Northern California that linked registry data, treatment, and GEP testing.
About a quarter (24.2%) of all patients received GEP testing, and 30% received chemotherapy. The patients who underwent testing were younger than those not tested (mean age, 56.2 years vs 60.7 years) and were most likely to have stage l than stage ll disease.
Patient who underwent testing and who were younger than age 50 years had lower chemotherapy rates than patients in the same age group who were not tested (53.0% vs 63.6%).
In contrast, older patients who were tested had higher rates of chemotherapy compared with the untested cohort (age 50 to 64 years: 36.5% vs 30.8%; age ≥ 65 years: 17.6% vs 8.2%).
These testing patterns showed that a greater proportion of tested than untested patients who were destined to have distant recurrences received chemotherapy (55.3% v 30.4%).
Preference-Driven Decisions
The overall cost-effectiveness ratio for testing vs usual care was $188,125 per QALY, but under more ideal conditions, it was $39,496 per QALY, which was closer to earlier estimates.
In another scenario, if the Oncotype DX costs were decreased from current Medicare reimbursement rates of $3416 to $2657, the ratio of community practice vs usual care decreased to $71,250 per QALY.
Finally, if the test properties of the assay improved, the incremental cost-effectiveness ratio decreased to $28,947 per QALY.
The accuracy of the test is important for cost-effectiveness, but the test assumes that patients are going to act on its recommendations, explained Dr. Mandelblatt. "If they are low risk they may forgo chemotherapy while those with high-risk results are recommended to receive chemotherapy, and that makes the cost-effectiveness more favorable."
But in the real-world setting, these are very much preference-driven decisions. "The earlier analyses assumed that everyone at low risk would forgo chemotherapy and everyone at high risk would receive it," she said. "In clinical practice, the reality is that some women at low risk are still worried about recurrence and want the chemotherapy, while others at high risk refuse it."
The test is also not perfect in predicting whose disease will recur; there are women in the low-risk group who will have distant metastases and those at high risk who will never experience a recurrence.
Dr Mandelblatt also pointed out that they selected Oncotype DX for their analysis because it is the most commonly used GEP test in the United States and was used in prior economic analyses.
Another test, MammaPrint (Agendia), is also available in the United States and was cleared for use by the FDA in 2007. The American Society of Clinical Oncology recently outlined specific recommendations for its use. But Dr Mandelblatt noted that it is more commonly used in Europe.
"The results for MammaPrint could be more or less similar, but that would depend on if it is more accurate than Oncotype DX," she said. "I haven't evaluated it, but it may be prone to the same issues that we found while assessing Oncotype DX."
The study was supported by grants from the National Cancer Institute, an American Cancer Society Mentored Research Scholar Grant, a Lombardi Comprehensive Cancer Center American Cancer Society Young Investigator Award, a Cancer Prevention Research Fellowship sponsored by the American Society of Preventive Oncology, and the Breast Cancer Research Foundation. The authors have disclosed no relevant financial relationships.
J Clin Oncol. Published January 8, 2018. Abstract
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