The National Comprehensive Cancer Network (NCCN) now recommends that patients with colorectal cancer (CRC) be tested for Lynch syndrome.
The syndrome is the most common inherited form of CRC, accounting for 2% to 4% of all cases. This translates to roughly 1 of every 35 CRCs.
The universal testing recommendation includes an optional age-related consideration: for CRC patients younger than 70 years, test everyone; for CRC patients 70 years and older, test only those who meet the Bethesda criteria.
“I’m a proponent personally of [testing] all colon cancer cases,” said Heather Hampel, MS, professor of internal medicine at the Ohio State University Comprehensive Cancer Center in Columbus.
With the option to screen only certain older patients, “I’m afraid that…no one over 70 will get screened,” she said during a presentation here at the NCCN 19th Annual Conference.
Hampel has been recommending screening for Lynch syndrome in all colorectal and endometrial cancer patients since 2006, as previously reported by Medscape Medical News.
The NCCN is housing this new recommendation in the Genetic/Familial High-Risk Assessment: Colorectal Cancer guideline. The guidance was formerly part of the Colorectal Screening Guideline.
The primary way to detect Lynch syndrome in CRC tissue that is either biopsied or surgically resected is with immunohistochemistry (IHC) or microsatellite instability (MSI) testing. The new guideline says that genetics counseling “is not required prior to routine tumor [tissue] testing” at a center.
If there is no tumor tissue available, certain patients can undergo genetics testing. In such cases, pretest counseling should be performed by a professional genetics counselor.
Tumor testing is a win for CRC patients; there is virtually no downside, said Hampel. The outstanding risk is for insurance discrimination. A 2008 federal law prohibits employment and healthcare insurance discrimination on the basis of genetic information. Still, this law, known as the Genetic Information Nondiscrimination Act, does not cover life insurance discrimination, she noted.
This is one of the reasons that counseling is advised when a person who has an immediate relative with Lynch syndrome considers undergoing genetic testing.
What Lynch Syndrome Means for CRC Patients
The identification of Lynch syndrome in CRC patients influences the subsequent management of their disease, including screening for other malignancies.
Hampel spelled out some of the key implications of Lynch syndrome for CRC patients. These patients have a 16% to 30% risk for a second primary CRC in the 10 years after their first diagnosis.
For this reason, NCCN guidance for CRC patients with Lynch syndrome differs from that for CRC patients without it. Patients with the syndrome should have a colonoscopy every 1 to 2 years for life. For those without the syndrome, colonoscopy is indicated 1 year after the cancer diagnosis, 1 to 3 years later, and every 3 to 5 years thereafter, depending on the findings.
Lynch syndrome patients also have a higher risk for other cancers.
For instance, women younger than 70 years have a 15% to 60% risk for endometrial cancer and a 1% to 24% risk for ovarian cancer (depending on which mismatch repair genes are implicated in the syndrome). In contrast, women in the general population have a 2.7% risk for endometrial cancer and a 1.6% risk for ovarian cancer.
Hysterectomy and bilateral salpingo-oophorectomy should be considered after childbearing, said Hampel. These procedures eliminate the risk for endometrial and ovarian cancers, she said.
Stomach cancer is also associated with Lynch syndrome; however, partial colectomy does not eliminate that risk.
Screening Already Underway
In a 2012 survey, 71% of National Cancer Institute (NCI) Comprehensive Cancer Centers reported that they routinely perform tissue testing (IHC/MSI) to screen for Lynch syndrome in CRC patients, said Hampel (J Clin Oncol. 2012;30:1058-1063).
However, the researchers acknowledged that not all Comprehensive Cancer Centers responded to the survey, which could have inflated the findings.
Notably, the survey found that this screening practice is not well adopted in community hospitals. Only 36% of responding community cancer centers with an accreditation from the American College of Surgeons reported routinely performing IHC/MSI testing of tumor tissue, as did only 15% of community hospital cancer centers.
National Comprehensive Cancer Network (NCCN) 19th Annual Conference. Presented March 13, 2014.
