While cancer clinicians are focused on helping their lung cancer patients feel better through prescribing treatments to battle their disease, health economists are focused on helping health insurers and health care systems and providers decide which treatments should be worth prescribing. “Increasingly physicians are being presented with health economic analyses in mainstream medical journals as a means of potentially influencing their prescribing,” stated D. Ross Camidge, MD, PhD, a research faculty at University of Colorado Cancer Center, in a news release. “However, it is only when you understand the multiple assumptions behind these calculations that you can see that they are by no means absolute truths.”
Dr. Camidge and colleague Adam Atherly, PhD, published an opinion paper, “Buyer Beware: Understanding the Assumptions Behind Health Economic Assessments in Personalized Cancer Care,” in Journal of Thoracic Disease, which addressed this phenomenon. First, health economists adjust the cost of treatment by considering the extra “units” of health gained from a treatment. This incremental cost effectiveness ratio (ICER) is defined as the cost per additional year of life or quality-adjusted year of life and is used to compare treatments for disease. However, a number of assumptions used to create these ratios hold a significant influence on the answer to the question, “Is it worth it?”
To illustrate, a study from a collection of Canadian hospitals, “Cost Effectiveness of EML4–ALK Fusion Testing and First-Line Crizotinib Treatment for Patients With Advanced ALK-Positive Non–Small-Cell Lung Cancer,” calculated two different costs per quality-adjusted life year gained for patients with ALK+ non-small cell lung cancer (NSCLC) who were treated with crizotinib over first or second line chemotherapy. The theme of the study was eloquently stated in the current opinion paper by Drs. Camidge and Atherly: “But what if we change some of the assumptions used in the Canadian model?”
From one angle that took into account screening for ALK positivity, actual cost of drug, and benefits or side effects, the cost was $255,970 per quality-adjusted life year. From another angle, which assigned the level of return to quality of life a value of 90% rather than the initially assumed 50%, ICER was dropped to $143,421 per quality-adjusted life year gained.
As a result of how pliable ICERs can be and the increasing familiarity of physicians with how best to prescribe drugs for specific diseases, the assumptions used to calculate a drug’s benefit may change in the future. Additionally, fewer requests for tests will lower the testing cost per treatable case. For example, if 50 patents are tested for ALK+ lung cancer for a total of $50,000, it costs $50,000 to find one case treatable with targeted therapy. Alternatively, if the way tests are ordered is optimized, the rate may change to five cases of ALK+ per every 50 tests, lowering the cost to $10,000 per treatable case.
“Something that might seem clear-cut from the outside really gets tricky and much less definite when you pull it apart,” said Dr. Atherly. “The cost per unit of health that is used to determine if a drug is or isn’t used seems like an unequivocal fact, but is often highly equivocal.”