Most people have never heard of Lynch Syndrome, but approximately one million Americans have inherited genes that cause the condition, which significantly raises the risk of developing several types of cancers, including colon cancer. Frequent screening can detect many of these cancers early, when they're easier to treat, yet only one in two people with Lynch Syndrome know they have the condition.
A new Columbia University study now shows that the benefits of identifying people with Lynch Syndrome-by screening relatives of patients with colon cancer-are substantial when it comes to preventing deaths from Lynch-related colon cancers.
"Our analysis shows that identifying Lynch Syndrome among colon cancer patients and their first-degree relatives would decrease deaths from colon cancer in these people by up to 79%," says the study's lead author Sheila Rustgi, MD, assistant professor of medicine at Columbia University Vagelos College of Physicians and Surgeons.
"We hope that by quantifying these benefits, we can help doctors convey the importance of screening to patients and at-risk relatives and increase the uptake of screening."
The connection between colon cancer and Lynch syndrome
Roughly 3% to 5% of people diagnosed with colon cancer have Lynch syndrome. Since few are aware they have the syndrome at the time of their cancer diagnosis, guidelines recommend that all newly diagnosed colon cancer patients get screened for the syndrome. Such screening affects treatment decisions, detects additional cancers earlier, and has been shown to improve patient outcomes and reduce overall health costs.
When a patient is found to have Lynch Syndrome, screening is also recommended for the patients' first-degree relatives, who have a 50% chance of having the syndrome themselves. However, only a third of these individuals are ever informed of this risk, and less than half of those are screened.
What the study examined
To quantify the impact of screening first-degree relatives-a practice called "cascade testing"-the Columbia researchers conducted a simulation experiment, using the latest available data on patient outcomes, cancer risks, and treatment and screening costs.
"Using this data, we asked what would happen if we conducted Lynch screening on three different generations of first-degree relatives, that is, on the parents, siblings, and children of patients newly diagnosed with Lynch-related colon cancer."
What the researchers found
The study found that Lynch Syndrome screening is clearly beneficial for all three groups of first-degree relatives, but even more so for younger generations.
"Normally, 20-year-olds wouldn't be screened for colon cancer for another 25 or 30 years," says Rustgi. "But knowing they carry Lynch Syndrome, they could be screened early and often, increasing the odds of detecting pre-cancerous lesions or early-stage cancers, which are highly treatable. The flipside is that this commits these individuals to colonoscopies every year or two-but it would save lives."
Even imperfect uptake of cascade testing would save lives, the researchers estimate: With every 25% increase in cascade testing, the researchers estimated an additional 20% decrease in colon cancer deaths.
More cascade testing would also lower overall health care costs. With increased uptake of cascade testing, the researchers report that the increased cost of more frequent colonoscopies would be offset by greater savings from a reduction in cancer treatment.
"Our data builds the case for developing better systems for cascade testing," says Rustgi. "At present, there are many barriers, including limited family communication, privacy concerns, inadequate insurance coverage, and lack of access to genetic counseling and testing. We need more studies of how to address these issues and improve the uptake of cascade testing."
References
Additional information
The study, "Cost-Effectiveness of Lynch Syndrome Identification Strategies in Individuals with Colorectal Cancer and the Impact on At-Risk Relatives," was published Feb. 24 in Clinical Gastroenterology and Hepatology.
The research was supported by the National Institute of Health (R01CA257333, R01 CA287257, and P30DK132710).
The other contributors are: Josephine Soddano (Columbia), Myles Ingram (Columbia), Heather Hampel (City of Hope National Medical Center), Chin Hur (Columbia), and Fay Kastrinos (Columbia).
