Ajay Bansal, MD
Newswise — Colorectal cancer is the second-leading cause of cancer-related deaths in the United States; only lung cancer ends more lives. It’s also largely preventable for most people who get regular colonoscopy screenings, during which doctors can remove precancerous growths known as polyps before they become malignant or reach an advanced stage.
For people with a genetically inherited disorder known as Lynch syndrome, however, colon cancer is much harder to prevent. Lynch syndrome affects 1 of 279 Americans. Caused by mutations in one of four associated genes, Lynch syndrome greatly increases the risk for colon cancer.
“The lifetime risk of colon cancer in the general population is approximately 4% to 5%,” said Ajay Bansal, M.D., professor of gastroenterology at the University of Kansas Medical Center and medical director of the Gastrointestinal Cancers Prevention Clinic at The University of Kansas Cancer Center. Speaking in an August episode of The University of Kansas Health System’s Morning Medical Update, Bansal continued, “In my high-risk clinic, for patients with other gene mutations, the risk is around 10% to 15%. With Lynch syndrome, it goes up to 30% to 80%.”
Bansal is leading a national clinical trial to test a combination vaccine to prevent colon cancer in people with Lynch syndrome. In this phase-2 trial, study participants at the 16 trial sites across the country receive a series of three vaccines, each of which is designed to create an immune response that targets a different protein involved in the formation of colon cancer. The researchers hope that the immune cells find and destroy any cells that harbor these rogue proteins before polyps or cancer develop.
“By testing these three vaccines, in combination with an immune booster, to generate high-quality immune cells in the body, it is almost like generating 24/7 bodyguards against cancer,” said Bansal. “We are hoping to decrease the risk of colorectal cancer, but one of the secondary things we are looking at is the risk of ovarian, uterine, stomach and other cancers, because some of those same proteins are also involved in causing cancer in other organs.”
The risk of a second cancer occurring in Lynch patients varies because it depends on the person’s specific gene mutations. Overall, the risk of a second cancer occurring is 20% to 60%, Bansal said.
Lori Chavez, who also appeared on the Morning Medical Update, had a family history of colon cancer. Nearly five years ago, after her sister tested positive for Lynch syndrome, Chavez was tested and learned that she also had the genetic disorder. Less than a year later, Chavez was diagnosed with colon cancer. She had her colon removed, and she also underwent a hysterectomy. Her oldest child was tested and is negative for Lynch syndrome, and her two other children are too young for testing. Chavez is a participant in the trial. “I’m doing this because I'm hoping by the time they're able to get tested, if they're positive, they can just turn around and there's a vaccine,” she said.
Visit the KU Cancer Center website for more information about this clinical trial.
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