Common Pitfalls of Head and Neck Research Using Cancer Registries

Objective: To highlight common pitfalls observed in scientific research derived from national cancer registries, predominantly the Survival, Epidemiology, and End Results Program and the National Cancer Database. Data Sources: Literature review and expert opinion. Review Methods: This state-of-the-art review consolidates the literature with editorial experiences describing how and why statistically flawed studies are usually rejected for publication, highlighting common errors in submitted articles employing national cancer registries. Conclusions: Pitfalls were identified in 2 major areas—design and data analysis. Design pitfalls included unbalanced cohorts, uncontrolled covariates, and flawed oncologic variables. Analytical pitfalls included incorrect application of univariate analyses, inclusion of inaccurate data, and inclusion of stage IVc disease in curative survival analysis. Additional limitations of database studies were identified, including absence of patient-related outcomes, hypothesis-generating vs practice-changing implications, and inability to differentiate between overall survival and disease-specific survival. Implications for Practice: Methodological strategies are suggested to ensure careful analytical design and appropriate interpretation. Although national cancer registries provide a wealth of data, researchers must remain vigilant when designing studies and analyzing these data sets. Inherent design flaws raise considerable problems with interpretation; however, when analyzed judiciously, registries can lead to a better understanding of cancer outcomes.