Inherited GI Cancers Take Center Stage at CGA Congress

Michelle Springer, CGC


December 23, 2022

In early November, the Collaborative Group of the Americas–Inherited Gastrointestinal Cancer (CGA-IGC) held its 26th annual conference and its first in-person version since 2019. It attracted over 300 international clinicians and researchers in hereditary gastrointestinal (GI) cancers from various specialties, including genetic counselors, gastroenterologists, surgeons, oncologists, and advanced practice providers.

The meeting kicked off with the Bert Vogelstein Lectureship, given this year by Fergus Couch, MD, who discussed moderate penetrance genes and cancer risk.[1]

Alicia Latham, MD, MS

This was followed by a series of talks related to the CHEK2 gene, including data from the MSK-Impact study potentially linking CHEK2 mutations to gastric and pancreatic cancers, presented by Alicia Latham, MD, MS.[2] This work expands the number of cancers that may be part of the CHEK2 spectrum, which now also includes hematologic and kidney/bladder cancers.

If there's a conclusion to be gleaned from these sessions, it's that we still have much to learn regarding moderate penetrance genes. Addressing this knowledge gap requires more population-based control studies and investigations into cancer risk across diverse ethnic groups.  

A Compelling Case for Genetic Testing in Colorectal Cancer

Bryson Katona, MD, PhD, from the University of Pennsylvania, offered new research with potentially practice-changing implications.

Bryson Katona, MD, PhD

Katona's presentation[3] coincided with the arrival of his team's manuscript[4] as part of a new partnership between CGA-IGC and JCO Precision Oncology to promote simultaneous publication of important data from oral plenary presentations.

Katona presented data on the yield of pathogenic variants from multigene panel testing from a diverse colorectal cancer population of over 34,000 patients (a brief summary video is available here).

His team found that 14% of all patients tested positive for a pathogenic variant in a hereditary cancer gene. Of note, clinically actionable variants were identified in 11.9% of patients with colorectal cancer; 9.1% of the variants were in a gene associated with colorectal cancer/polyposis risk, and 3.1% were found in a non–colorectal cancer gene.

This is the largest study to date examining the use of multigene panel testing in a diverse colorectal cancer population. Although there remains debate on the subject, such results indicate that universal genetic testing for colorectal cancer could be right around the corner.

Weighing the Risk for Inherited Cancer in Reproductive Decisions

The second day of the CGA-IGC meeting featured presentations related to reproductive considerations for individuals with inherited cancer syndromes.

Andria Besser, MS, genetic counselor and director of Reproductive Genetics at NYU Langone Fertility Center, discussed the use of preimplantation genetic testing (PGT) for individuals who carry hereditary cancer mutations, and stressed the importance of providing patients with information regarding this option.[5]

Backed by the American Society of Reproductive Medicine, the use of PGT for single-gene disorders has increased significantly in recent years. Challenges that remain include the potential financial burden as well as technical considerations with the custom assay that is used.

Sukhkamal Campbell, MD, an obstetrician-gynecologist at the University of Alabama at Birmingham, discussed fertility preservation options for patients with hereditary cancer syndromes,[6] emphasizing that all major organizations, including the American Society of Clinical Oncology, American Society of Reproductive Medicine, European Society of Human Reproduction and Embryology, and the European Society of Medical Oncology, recommend fertility preservation counseling.

These presentations highlight the necessity of counseling on reproductive considerations and fertility preservation for our patients.

Novel Approaches to Expanding Genomic Services

The need for genetic testing in patients and their family members is outpacing the number of available genetic counselors. As a result, organizations continue to explore alternative approaches to accessing genetic testing. Several speakers explored such methods for increasing access to genetic services, including the use of advanced practice providers, online genetic education, chatbots, and telephone visits.

Anita Gregory, MD, and her team from St. Joseph Hospital Center for Cancer Prevention and Treatment presented data on a novel approach to genetic testing: a walk-in clinic staffed by genetic counseling assistants for patients with a cancer diagnosis.[7] This streamlined approach is an intriguing delivery method that offers same-day genetic testing to its patients. As the criteria for genetic testing continue to expand, so must our delivery approaches and the accessibility to testing.

Innovative Techniques in Colonoscopy

David Hewett, MBBS (Hons,UQ), MSc, PhD, from the University of Queensland in Australia, gave one of the final talks at the meeting.

Hewett's research focuses on innovative techniques to improve colonoscopy performance, and his presentation explored the use of artificial intelligence (AI) in colon cancer screening and surveillance.[8] As the effectiveness of colonoscopy is highly operator-dependent, it lends itself as a perfect candidate for AI. Hewett presented data from over 12 studies demonstrating that the adenoma detection rate (ADR) can be increased by 10%-12% with the use of AI.

Although this number may not seem overly significant, Hewett asserted that a 10% increase in ADR can decrease colorectal cancer rate by an astounding 50%.[8]

As the medical field starts to incorporate AI into various applications, including this type of training into medical programs will be extremely important.

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