New Study Shows 1 in 6 Colon Cancer Patients Have Hereditary Gene Mutations; The Importance of Genetic Testing

The study, published in Clinical Gastroenterology and Hepatology, reported that researchers at the Mayo Clinic found “1 in 6 patients with colorectal cancer had an inherited cancer-related gene mutation, which likely predisposed them to the disease.”

In addition, the researchers discovered that 60% of these cases may not have been detected if relying on a standard guideline-based approach.

“We found that 15.5% of the 361 patients with colorectal cancer had an inherited mutation in a gene associated with the development of their cancer,” says Dr. Niloy Jewel Samadder, a Mayo Clinic gastroenterologist and hepatologist, who is the study’s senior author. “We also found that over 1 in 10 of these patients had modifications in their medical or surgical therapy based on the genetic findings.”

The Importance of Genetic Testing

We know that some cancers, like colon cancer and breast cancer, can be hereditary. That’s why it’s important to know your family cancer history and get tested for gene mutations like BRCA1, BRCA2 and Lynch syndrome.

Related: What is Lynch Syndrome? And Why Is it Important to Know About for People Fighting Cancer?

Dr. Michael Birrer, professor at the University of Alabama BirminghamUAB Comprehensive Cancer Center, explains the importance of genetic testing in an earlier interview, particularly as it pertains to ovarian cancer.

Related: Minority Communities Are Not Receiving Adequate Genetic Testing For Breast & Ovarian Cancer, Study Finds; This Can Be a Life-Saving Resource

“How does genetics play a role in managing patients? This part of the field has really radically changed,” says Dr. Birrer. “Our understanding of the role of genetics in the development of ovarian cancer has evolved very rapidly in the last five to 10 years. So it used to be the dogma that about 8% of ovarian cancer had a family history. And those are the patients who had some sort of genetic basis. We now know that that’s not true.”

“It’s more likely about 20% of ovarian cancer patients who come in the door of the clinic actually have a germline abnormality, either in BRCA1 or 2 or one of the other genes in the Fanconi pathway. So you have to focus on that and realize what that means. 3/4 of those patients of that 20%, 3/4 of them, have no family history. They don’t know that they have a genetic abnormality.”

“And these patients used to be treated, and we would never really understand that or counsel them,” he says. “And they would pass that gene on to their kids with dire consequences.”

The Importance of Genetic Testing and Maintenance Therapy

Screening for Colon Cancer

Colon cancer is screened for via colonoscopy, a procedure that looks for polyps small growths on the colon. The majority of polyps are cancerous. Dr. Zuri Murrell, a colorectal surgeon at Cedars-Sinai explains in an earlier interview what happens during this procedure.

Related: Colon Cancer Screening is Extremely Important; Guidelines Now Say to Start at Age 45 if There Is No Family History

“People often ask me, what do you do when you have a colonoscopy? What’s done? Do you do biopsies? So a colonoscopy can be done for many things,” says Dr. Murrell. “But when we’re looking at a colonoscopy for colorectal cancer screening, what we do is we’re looking for polyps, which are these small growths. When we see a polyp, we actually physically take the polyp out through the colonoscope.”

“What does that mean? That means we basically put a wire through with a little bit of a little flange at the end and we pull the polyp out. What happens is then when we take the polyp out, we send that to a lab. So when it’s in the lab, a pathologist basically cuts up the little polyp and looks under a microscope. And underneath the microscope, they can decide whether or not it is early cancer or whether it is just a precancerous polyp,” he says.

“95% of polyps are precancerous polyps. And what does that mean? That means that it’s not a cancer yet. But it would have been a cancer ultimately if you just let it grow and grow and grow.”

Looking for Polyps During Colonoscopy

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