Risks of malignancy in the major nongynecologic cytopathology reporting systems: Critiques and discussions

The ever-increasing popularity of standardized systems for reporting cytopathology has led in part to much attention to and importance of the risk stratification schemes, especially the risks of malignancy (ROMs), which are associated with the different diagnostic categories and upon which recommendations for clinical management are based. However, it is well known that the ROM calculations are based on retrospective reviews of the existing literature, representing a heterogeneous patient population, and are plagued by significant biases and variations. Statistically, the ROM represents the post-test probability of malignancy, which changes with the test result and with the prevalence of malignancy (or pretest probability) in an individual practice setting and individual patient presentation. Therefore, the clinical utility of the ROM is questioned and likely needs a second look in the nongynecologic cytopathology reporting systems. In this communication, the authors discuss the status of the ROM estimates according to the most commonly used nongynecologic reporting systems, including for thyroid, salivary glands, and others, highlighting similarities and differences with a focus on the limitations of ROM estimates and their application in clinical practice.