by Dr Silvia Sanduleanu, MD, PhD

Within the WEO Colorectal Cancer Screening Committee, chaired by Professor Linda Rabeneck, there are seven Expert Working Groups (EWGs), created to promote dialogue on particular issues within the field of colorectal cancer screening and facilitate consensus on controversial areas.

The WEO hopes to shed a light into the important work from these EWGs, in a series of articles.
The EWG ‘Right-sided lesions and interval cancers’ is headed by Dr Silvia Sanduleanu, MD, PhD, Division of Gastroenterology and Hepatology, Maastricht University Medical Center, The Netherlands.

The goal of the EWG ‘Right-sided lesions and interval cancers’ is to create an international platform to monitor and compare interval cancer (IC) rates across programs and to establish international benchmarks. Main points of the roadmap include: i) to standardize the nomenclature for an IC. – this work was recently published in Gut (Sanduleanu, leClercq…Schoen et al, Definition and taxonomy for interval colorectal cancer: a proposal for standardising nomenclature, Gut 2015; 64(8):1257-67); ii) to describe the procedure for monitoring and reporting IC; iii) to develop criteria for evaluating the most likely explanations for IC – missed, incompletely resected polyps or newly developed cancers; and iv) to propose targeted interventions to optimize the quality and effectiveness of screening for CRC and colonoscopy surveillance.

During the latest EWG meeting, held at DDW 2015 in Washington, the group discussed several key questions to address these needs: how to set up cancer registries and screening databases to facilitate monitoring IC, what parameters and how to monitor and what should be the practical steps for monitoring IC in practice.

Several speakers were invited to present data on IC from nationwide and regional CRC screening programs with different test modalities, including Professor Catherine Dubé (Ontario, Canada), Professor Han-Mo Chiu (Taiwan), Professor Finlay Macrae (Australia), Professor Takahisa Matsuda, (Japan) and Professor Douglas Robertson (USA).

In closing up the discussion, the group agreed that high-quality screening databases and cancer registries are critical to set the scene for international benchmarking. Better communication will improve uniformity of data collection and enable comparison across programs. Another key take-away message was that the crosslinking process between databases can be challenging, as it requires a structured and multidisciplinary approach to avoid both under- and overestimation of IC rates (Sanduleanu, Dubé, Gut 2015; 64(8):1188-90). Next, the method for calculating IC rate needs clarification – several methods can be employed to serve specific goals. While IC rate will never be zero, to optimize the quality of screening, IC rate should be minimized. The EWGs convene at least once a year, and hope to provide an open forum for experts interested in the area.