Evaluation of New Tests

New non-invasive screening tests for colorectal cancer (CRC) and its precursor lesions are rapidly emerging as novel technologies to identify new biomarkers for detecting these neoplasms, using a range of biological samples.  The Expert Working Group on The Evaluation of New Screening Tests aims to provide a dynamic framework for evaluation of new non-invasive CRC screening tests which is flexible yet rigorous and allows for broad application given the wide global variation in how CRC screening is conducted.  This recognizes that one size does not fit all when considering differences in population-based organized screening programs based on a WHO-style public health models and structured opportunistic screening, and differences in what is acceptable to regulatory agencies. The goal is  to ensure a test’s suitability for the context of its use, no matter how the screening program is implemented, without requiring necessarily requiring randomized trials with CRC mortality as the end point.

The Expert Working Group recently completed a consensus process toward this goal to provide an efficient, feasible and rigorous approach to evaluating emerging ‘new’ non-invasive tests for use in the different screening contexts, the results which were published in the journal Gut

An efficient strategy for evaluating new non-invasive screening tests for colorectal cancer:  guiding principles. Gut 2023; 72:1904-1918.

This highly successful international collaboration involved 47 experts (gastroenterologists, endoscopists, GI surgeons, public health physicians, epidemiologists, clinical biochemists and tumor biologists) with knowledge or experience in practice or research relevant to screening for CRC. It outlined a phased strategy for evaluation of new non-invasive CRC screening tests, irrespective of the type of biological sample studied, and provided an efficient and manageable method of reaching a clear understanding of the potential benefits and liabilities of new screening tests essential to furthering the goal of minimizing the disease burden of CRC. It also highlighted challenges, such as inclusion of adjustable test end points in order to achieve a test configuration best suited for a range of program goals, uncertainty about how to define those precursor lesions most at risk and the need for modelling parameters that enable prediction of test impact on CRC mortality and incidence.

The Expert Working Group is currently engaged in two follow-up projects:

• A special journal issue expanding on the many themes and principles outlined in the consensus process which is fully commissioned and expected to publish in early 2025
• An examination of the concept of adjustable test end points in order to achieve a test configuration best suited for a range of program goals, with FIT as the model test