PHILADELPHIA– Despite evidence that screening reduces morbidity and mortality, even patients at high risk for Lynch syndrome (LS) are not being routinely evaluated, according to a comprehensive survey undertaken from a cancer registry and presented at the American College of Gastroenterology (ACG).
The survey, funded by the Centers for Disease Control and Prevention and undertaken in Louisiana, found that only 23% of patients who developed colorectal cancer (CRC) before the age of 50 years underwent even the first step in screening. The figure should be 100%, reported Dr. Jordan J. Karlitz, director, GI Hereditary Cancer and Genetics Program, Tulane University, New Orleans.
In addition, the majority of those who were screened were evaluated on the basis of tissue specimens taken at the time of cancer resection rather than at the initial colonoscopy. This is important because the presence of LS changes management, particularly the extent of resection.
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Even with patients at high risk for Lynch syndrome are not being evaluated regularly enough, says a new survey.
“These data suggest that more effective protocols need to be put in place for ensuring that patients at risk are screened preoperatively using a time-efficient, multidisciplinary approach,” Dr. Karlitz reported.
The study was conducted in the context of recently revised guidelines, such as those from the National Comprehensive Cancer Network, that now recommend screening for LS in patients at any age with CRC.
“If the indications were being expanded, we wanted to know how well we were doing in those we already know are at high risk,” Dr. Karlitz said in an interview.
The answer was not very well. There were 274 patients under the age of 50 years found among a total of 2,427 CRC patients in the Louisiana Tumor Registry Comparative Effectiveness Research Project. In this group, microsatellite instability (MSI) analysis or immunohistochemistry (IHC) assays, which are the first steps in screening, had been performed in as few as 6% of young CRC patients in rural hospitals. Comprehensive tertiary care centers did better, but those rates only climbed to 40%.
Of those tested, abnormal MSI or IHC were seen in 20%, emphasizing that the yield is high in this population. Although confirmation of LS requires further germline genetic studies, the first step of MSI or IHC screening is critical.
The fact that screening for many patients was undertaken only after cancer resection is another worrisome finding, according to Dr. Karlitz, suggesting “a problem in the process.”
Asked for a comment, Dr. Dennis J. Ahnen, professor of medicine, University of Colorado, Denver, agreed. He suggested that both the low rate of screening for LS in a high-risk population and the failure to conduct the screening from tissue obtained at the initial colonoscopy suggest a need for protocols that will expedite appropriate intervention.
“The screening for Lynch syndrome has to be done at the time of diagnosis to ensure that these patients are managed optimally,” Dr. Ahnen suggested. “We need to perform MSI or IHC and the genetic testing prior to surgery.”
According to Dr. Karlitz, the best approach may be the development of protocols involving a multidisciplinary team so that the steps to screening, diagnosis, and patient management are well outlined.
“Improving our ability to screen for Lynch syndrome is not only important for the patient with CRC but for counseling family members who may also be affected,” Dr. Karlitz suggested. “This is a serious issue, because we know that missed Lynch syndrome is associated with an increased morbidity and mortality.”