Purpose: Guidelines are published for referral to genetic counseling and multigene panel genetic testing for colorectal cancer. We hypothesize that these guidelines are not recognized in practice, resulting in the underreferral of patients to genetic counseling. We aimed to investigate the clinical impact of these guidelines.
Methods: This was a retrospective cohort study conducted using a single academic-institution colorectal cancer patient registry. The registry included all patients ≥18 years old with a pathologic diagnosis of colon cancer, rectal cancer, or polyposis from January 2018 to January 2020 with complete chart data to determine inclusion into the genetic referral cohort.
Results: Out of 225 colon cancer patients, 92 met criteria for referral to genetic testing, but only 56 patients obtained referral and 39 completed testing. For rectal cancer, 29 out of 127 patients met criteria for referral, but only 11 obtained referral and 8 completed testing. Actionable variants, defined as pathogenic or likely pathogenic, were identified in 18 colon cancer and 5 rectal cancer patients. Age made a significant difference in the referral rate for colon cancer (P = 0.02) but not rectal cancer (P > 0.05).
Conclusion: Our study demonstrates poor adherence to guideline-based genetic testing. These data emphasize the need for more consistent referral to genetic testing for diagnosis of underlying inherited cancer syndromes.
Keywords: Colorectal neoplasms; evidence-based medicine; genetic testing; hereditary nonpolyposis.
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