Why doctors of cancer patients say their relatives should be tested
While it is becoming easier and more affordable for consumers to be tested for gene variations linked to cancer, there’s a dearth of testing among cancer patients’ relatives. Some health care providers say that robs them of both early detection and knowing to take steps that may forestall cancer completely.
The Wall Street Journal this week writes of Dr. Shoshana Ungerleider, whose father’s diagnosis of pancreatic cancer added a strong ripple to her own future health. Through genetic testing, it was discovered that he had a mutation of the BRCA2 gene, which increases the odds of pancreatic, breast and ovarian cancer.
The risk is autosomal dominant, meaning his children would have a 50% chance of inheriting the mutation — and should they have it, the potential of not just the associated cancer, but 50-50 odds of passing it on to their children.
About 10% of cancers are known to have possible genetic links, The Wall Street Journal article noted. Knowing one has increased risk opens the door to preventive measures, lifestyle changes and earlier detection.
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Simpler gene testing
Testing used to be much more expensive — and usually required an appointment with a genetic counselor to explain what one’s findings meant. That’s no longer necessarily true.
In 2018, the U.S. Food and Drug Administration authorized direct-to-consumer testing via the Personal Genome Service Genetic Health Risk Report for the BRCA1/BRCA2 gene mutations linked to breast cancer. It is designed to say if some are at increased risk of breast and ovarian cancer and if men could have an increased risk of breast cancer and prostate cancer linked to three of the known BRCA gene mutations. It doesn’t say if they could have a higher risk from other mutations. Consumers were warned not to make treatment decisions based on the test, but to work with their doctor.
The year before, the FDA made it much easier and cheaper to be tested for some genetic variants — certainly not just cancer — allowing consumers to complete their part of the process at home, privately. The agency approved 23andMe’s personal genetic test, which looks for gene variants related to 10 conditions, including Alzheimer’s, Parkinson’s, celiac disease and a number of others, as NPR reported.
Other gene variants have since been added, including for certain cancers. But the tests are not supposed to be diagnostic by themselves. They show variants and the company says people with a variant should consult a health care professional.
At the time of the approval, Sharon Terry, the CEO of the Genetic Alliance, a nonprofit advocacy group for those with genetic disorders, told NPR: “Women learn they are pregnant using a test directly marketed to them and buy it off the shelf in a drugstore. In 10 years we will marvel that this is an ‘advance’ at all. Imagine pregnancy tests being only available through a doctor.”
In announcing streamlined review of genetic health risk tests, then-FDA Commissioner Dr. Scott Gottlieb said, “While these tests can offer significant amounts of personal risk information, they’re not without their own risks — especially if they provide consumers with incorrect or misleading information that may be used to make health choices without considering the advice of a medical professional. Consider the consequences of a person who is told they’re not at risk for coronary heart disease and incorrectly opts to forgo dietary changes or drugs that reduce their risk of heart attack and death.”
Other companies have also now produced tests that target various cancers, including lung, prostate, kidney and pancreatic cancer, among others.
The prices have dropped
And where gene testing once cost thousands of dollars, screening tools are now available at a fraction of that cost.
For those with a cancer diagnosis already, gene testing also creates an advantage. A 2020 study in the journal JAMA Oncology of nearly 3,000 cancer patients said that gene testing for variants allowed more targeted, modified treatment for 30% of them. It concluded that “universal genetic testing detected more clinically actionable variants than a guideline-based approach, with a significant association with clinical management for the patients and their families.”
When cancer patients had testing for variables that might be heritable, it also opened the door for their close relatives to get information that could help them detect early or possibly prevent cancer, the study found.
