We’re Underutilizing Genetic Testing for Colorectal Cancer
The colorectal cancer outlook is bleak in the US and abroad. In the United States, colorectal cancer is the third most commonly diagnosed cancer, excluding skin cancers, according to the American Cancer Society. It is also the fourth leading cause of cancer related death. In general, the lifetime risk of developing colorectal cancer is about one in 23 for men and one in 25 for women, with a recent increase in incidence among people under 50 years of age. Worldwide, more than 1 million cases they were diagnosed in 2020 and were expected to cause more than half a million deaths in the same year.
With these factors in mind, determining whether there is a genetic cause of a patient’s colorectal cancer is crucial to identifying and applying precision therapy approaches to treat the patient. Around 20% of colorectal cancer cases it may be related to hereditary factors, although estimates vary. By understanding an individual patient’s risk, we can better implement screening strategies aimed at early detection and better outcomes for patients and their family members at risk.
As an oncologist dedicated exclusively to the treatment and research of patients with gastrointestinal tumors, I witness daily the significant impact of the implementation of Germline Genetic Testing (GGT) in my practice. The benefits go not only through the stratification of the risk of developing tumors for the patient and her relatives, but also through the incorporation of highly effective therapeutic options such as immunotherapy. Although studies offer evidence of the clinical utility of genetic test for patients with colorectal cancer, recent research found that there is a gross underutilization of GGT for colorectal cancer patients, even when universal GGT for colorectal cancer patients is backed by a medical insurance policy. This underutilization of GGT is a major inhibitor to disease management and obstructs patients’ access to precision therapies, clinical trials, and treatments based on published management recommendations.
Based on findings from multiple studies, the National Comprehensive Cancer Network (NCCN) recently made GGT universal. the standard of care for all patients with colorectal cancer. However, genetic testing has not been systematically implemented as part of the standard of care in oncology, both for colorectal and other cancers, despite its positive impact on disease management. This was demonstrated in the aforementioned underutilization study, where less than 5% of eligible colorectal cancer patients received GGT. He study shows that clinically actionable genetic data is not available for patients diagnosed with colorectal cancer, despite universal eligibility for screening according to NCCN guidelines.
In addition, the most diverse study to date examining germline multigene panel testing in patients with colorectal cancer was recently posted, further supporting the need for universal GGT as the standard of care for all colorectal cancer patients. Overall, 14.2% of patients had a pathogenic variant, and most had variants with established clinical potential: 9.1% were in genes associated with colorectal cancer and/or polyposis, and 3 An additional .1% had a clinically actionable variant. Pathogenic actionable variants confer an indication for precision therapy, potential eligibility for clinical treatment trials, or application of established gene-specific management recommendations.
Considering that perhaps as few as 5% of colorectal cancer patients currently have the opportunity to undergo GGT, we as the medical community must find ways to address barriers to implementation of current evidence-based universal testing policies. evidence supporting precision treatment and optimal management of patient care. The lack of medically necessary, guideline-supported universal GGT for colorectal cancer is leading to missed opportunities, including the best precision treatment options (such as immune checkpoint inhibitors) and clinical trial enrollment with targeted therapies. Furthermore, the lack of personalized prevention can perpetuate health disparities in colorectal cancer.
The time has come for clinicians to better understand and take advantage of GGT as a reflex test for all patients with colorectal cancer. To win the battle against one of the most common and deadly cancers, we must overcome the barriers to GGT in colorectal cancer and implement universal GGT as part of the standard of care for cancer in daily medical practice.
Dr Peter Uson, is an oncologist who works at the Personalized Medicine Center of the Albert Einstein Israelite Hospital in São Paulo. He is also a researcher at the Mayo Clinic in Phoenix, Arizona.