All Patients With Colorectal Cancer Should Be Genetically Screened
Published Online: Monday, May 7, 2012
DNP, APRN, CNS, AOCN®
“Initial screening should be a combination of high-tech and high-touch,” said Patricia Kelly, DNP, APRN, CNS, AOCN®, Texas Health Presbyterian Hospital, Dallas. “We want oncology nurses to be advocates for screening for LS.”
LS is an autosomal dominant condition that conveys an increased risk for colorectal cancer of about 50% for females and 80% for males. In addition, the age of cancer onset is earlier than for sporadic cancers, and extracolonic cancers—especially uterine, ovarian, and stomach—are also common in affected persons. It is estimated that screening interventions could reduce the risk of colorectal cancer in persons with LS by 60%.
In 2009, the Evaluation of Genomic Applications in Practice and Prevention (EGAPP) Working Group recommended that all newly diagnosed colorectal cancer patients be offered genetic testing—ie, “universal tumor testing”—though a specific testing approach was not singled out (Genet Med. 2009;11:35-41).
Kelly said screening is important because “family history does not ‘tell all’” or may not be evaluated; LS patients are at greater risk for second malignancies; at-risk relatives benefit from genetic testing and preventive strategies; and there are incremental cost savings that are estimated to be $36,200 per life-year gained.
What Preliminary Screening IncludesThe first step in universal screening for LS is immunohistochemistry (IHC), which will identify germline (inherited) and somatic (sporadic) mutations. Depending on the IHC findings, patients will either require no further testing or be referred for genetic sequencing analysis or BRAF mutation and methylation analyses. Microsatellite instability (MSI) testing can be done concurrently or subsequent to IHC, usually when IHC reveals abnormal mismatch repair proteins (MSI-high tumor points to LS).
Assessing Family HistoryBridget LeGrazie, RN, MSN, AOCN®, APNG, Virtua Fox Chase Cancer Program, Philadelphia, Pennsylvania, discussed the family history component of LS. She said patients should be suspected of having LS if they meet the Amsterdam criteria “3-2-1 rule”:
- 3 or more relatives with an associated cancer (colorectal cancer or cancer of the endometrium, small intestine, ureter, or renal pelvis); one should be a first-degree relative of the other two
- 2 or more successive generations affected
- 1 or more relatives diagnosed before the age of 50 years (though the average age of LS diagnosis is 61, and, therefore, this point may be less important)
Get Your Institutions InvolvedKelly concluded that in spite of the EGAPP recommendations, a recent survey indicated that most institutions have not established a tumor screening initiative. Universal screening was not being performed at 29% of National Cancer Institute–designated cancer centers, in 64% of American College of Surgeons–designated comprehensive cancer centers, and in 85% of community cancer centers that responded to the survey (Beamer LC, et al. J Clin Oncol. 2012;30:1058-1063).
“Clearly, there’s work to be done,” she told nurses. “If you don’t have universal screening at your institution, ask why. You can be a leader in this and make a difference.”
Nurses can at least “put evidence into practice,” LeGrazie added, by establishing a protocol for identifying patients for genetic referrals and referral resources.
For additional information on LS, read our spotlight on the advocacy group Lynch Syndrome International.
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