Efficacy-effectiveness gaps in oncology: Looking beyond survival

The efficacy-effectiveness (EE) gap describes the differences in survival seen in clinical trials and routine clinical practice, where patients in real-world practice often have inferior outcomes compared to trial populations. However, EE gaps may exist beyond survival outcomes, including gaps in quality of life, toxicity, cost-effectiveness, and patient time, and these EE gaps should also influence patient and clinician treatment decisions. Failure to clearly acknowledge these EE gaps may cause patients, clinicians, and health care systems to have unrealistic expectations of the benefits of therapy across a range of important clinical and economic domains. In this commentary, the authors review the evidence supporting the existence of EE gaps in quality of life, time toxicity, cost and toxicities, and urge for further research into this important topic.