Sorting Through Screening Protocols for Colorectal Cancer

Who should receive genetic counseling and screening for colorectal cancer (CRC)? And how early should annual colonoscopies happen once those at risk are identified? These are important questions with equally important and complex answers.

Heather Hampel, MS, CGC, of the Ohio State University Comprehensive Cancer Center, took those questions on in an information-packed hour at the 19th annual conference of the National Comprehensive Cancer Network (NCCN)—Advancing the Standard of Cancer Care. Hampel spoke Thursday, March 13, 2014, as the conference opened in Hollywood, Florida.

Questions about genetic testing for CRC start with “need”: The origin of 10% to 30% of CRC is familial, while 65% to 85% is sporadic,¹ with another 1% caused by familial adenomatous polyposis (FAP) and 3% by hereditary nonpolyposis colorectal cancer (HNPCC), or Lynch Syndrome (LS). When a family risk is known, proper counseling and screening can identify those CRC patients who need different treatment options, as well as identify family members who may be at risk for other cancers associated with LS.

Genetic counseling is important, however, as Hampel would explain. Families are not as large as they once were, so it may not be as easy to detect a family history of CRC. On the plus side, wider use of colonoscopy is detecting polyps and cancers earlier, when the disease is more treatable, than was the case in previous generations. The presence of LS in the family makes all the difference in terms of the approach to screening and possible prophylactic options, as CRC is not the only cancer family members face; others include ovarian, urinary tract, and even skin cancer.

When LS is present in the family, depending on the mutation, colonoscopy should begin as early as age 20 and occur every 1 to 2 years for those family members who carry the mutations. Colonoscopies could move up to as early as 5 years prior to the earliest known colon cancer in the family.

There is no clear evidence for some other forms of screenings, including endometrial sampling, transvaginal ultrasound, and esophagoscopy gastroscopy duodenoscopy with extended duodenoscopy, but Ms Hampel said that clinicians could consider the latter, starting between the ages of 30 and 35. Urinalysis could be considered also, starting between the ages of 25 and 30. The most important element, of course, is getting a good family history starting at age 25.

Ms Hampel said that despite the challenges LS may present, there is good news: the cost for genetic panels and tumor screening has come down. Tumor screening costs about $500, and the cost for all LS mutations using Sanger Sequencing is about $4550. Next-generation sequencing costs are lower, ranging between about $2700 and $4000 for 14 to 20 CRC genes per panel. The technology is better, which is why the cost is lower, but it does take somewhat longer than it once did to get results. Ms Hampel said this is a cost-effective option for families in which more than 1 gene is involved.

Fears that families had in the past about getting genetic tests have eased with the passage of the Genetic Information Nondiscrimination Act, which offers protection in health coverage and employment based on results of genetic tests. However, Ms Hampel warned that the same is not true in life insurance, disability, and long-term care coverage, and she encourage those attending the NCCN session to counsel patients to have these forms of coverage in place before proceeding with genetic testing.

REFERENCE

1. Burt RW. Familial risk and colorectal cancer. Gastroeterol Clin North Am. 1996;25(4):793-803.