5 Things About Cancer, Genetics, and Germline Screening

December 6, 2019

Here are 5 things to know about genetic testing in cancer care.

This week, the National Comprehensive Cancer Network (NCCN) released a new set of updated guidelines for who should have genetic testing to understand their genetic risk assessment for breast, ovarian, and pancreatic cancers.

Here are 5 things to know about genetic testing in cancer care.

1. Increased Use of Gene Panels

As next-generation sequencing (NGS) techniques have evolved, the use of multigene testing for hereditary forms of cancer has changed the testing landscape for patients, relatives who may be at higher risk, and their families. The new NCCN guidelines include revised principles of risk assessment and counseling. For instance, they suggest that there may be a role for multigene testing in people who tested negative for a single syndrome, but whose personal or family history may suggest an inherited susceptibility. Health history may be explained by more than 1 inherited cancer syndrome, so a multigene panel test may be more efficient and cost-effective and increase the likelihood of a discovery that could direct future medical management.

2. Evolving Payer Issues

Health insurance companies vary when it comes to coverage for testing. In the August 2019 issue of Evidence-Based Oncology, one article noted that some payers, such as Blue Shield of California, Anthem, and Aetna, will cover testing to verify BRCA 1/2 findings discovered by direct-to-consumer tests such as 23andMe; while the tests are not medical grade, verifying the accuracy of a possible mutation early could save healthcare costs down the line. However, CMS has thus far taken the approach that it will not cover genetic testing until a patient develops cancer, a position that has drawn criticism. Earlier this year, a national coverage decision was reopened; at the end of January 2020, CMS is expected to issue a final National Coverage Determination decision on NGS for beneficiaries with advanced cancer.

3. Expanded Knowledge of Mutations

Germline mutations are associated with an increased risk of a variety of cancers, and they are unique in that the risk for certain cancers may be passed from parent to child. Unlike tumor tissue testing, which looks for mutations that occur after a malignancy develops, germline testing is performed on blood or saliva. The most common mutations are among Lynch syndrome and BRCA1/2 genes, affecting approximately 1 in 279 and 1 in 400 Americans, respectively. Besides BRCA 1/2, the guidelines released this week pulled together management recommendations for ATM, BARD1, BRIP1, CDHi, CDKN2A, CHEK2, MSH2, MLH1, MSH6, PMS2, EPCAM, NBN, NF1, PALB2, PTEN, RAD51C, RAD51D, STK11, and TP53 for different cancers.

The guidelines also caution that given advances in screening, cancer survivors who had a negative genetic test more than a decade ago should consider seeking additional testing. Facing Our Risk of Cancer Empowered (FORCE), a nonprofit organization that advocates for families facing hereditary cancer, stresses the importance of knowing the risk so that actionable steps can be taken, if necessary.

4. Misconceptions About Mutations

Many people associate BRCA mutations with breast and ovarian cancer and mistakenly think they, and other genes that contribute to cancer, don’t affect men, according to FORCE. Men with BRCA 1/2 can pass it to children and are at higher risk for not only breast cancer but also melanoma and pancreatic cancer.

5. Misconceptions About Cancer Risk

While this is the season where consumer genetic testing kits are hawked as gifts to give family members in every online shop or pharmacy, inherited cancers make up only 5% to 10% of cancers, and moreover, for most cancers, the number of actionable genes is just a few dozen. Most Americans worry about factors over which they have no control, such as their genes, while overlooking the lifestyle factors that do make a difference. About 42% of cancer cases and 45% of cancer deaths are related to obesity, physicial inactivity, and poor diet. In other words, it might be better to forgo the second piece of pie this month and go for a jog around the block—right past the drugstore.