Colorectal Cancer Screening: Latest Guidelines, New Research

Colorectal Cancer Screening: Latest Guidelines, New Research
During CRC Awareness Month, discussing ACS screening guidelines and a moonshot to explore the GI microbiome.

March is National Colorectal Cancer Awareness Month. In this interview, Timothy Geiger, M.D., discusses key elements of the 2018 updates to the American Cancer Society (ACS) guidelines for colorectal cancer screening. Geiger also previews a major initiative at Vanderbilt University Medical Center to advance colorectal cancer prevention and diagnosis. Geiger is chief of the Division of Surgery and director of the Colon and Rectal Surgery Program at Vanderbilt.

Discover:  Last year, the ACS moved its recommended screening age for colon and rectal cancer from age 50 up to age 45 for average-risk patients. What research or changes in thinking informed that update?

Geiger:  In the traditional model that we’ve used to approach colorectal cancer, age 50 has been the point at which the number of cases picked up by colonoscopy increase to the point that it’s worth the risk of undergoing a colonoscopy. Now we are seeing data showing that, as more patients get colon and rectal cancer earlier, the tipping point has shifted.

Discover:  The ACS emphasizes choice in screening options for average-risk patients. Why is choice a key emphasis within the guidelines, and what is your view of the recommended choices?

Geiger:  There are, of course, multiple ways to test for colon and rectal cancer, including invasive and non-invasive options. When choosing a test, a patient should talk with their primary care physician or gastroenterologist about the comparative risks and benefits. Some tests are as simple as doing stool samples, and the most invasive test would be a colonoscopy, which is the most well-known.

A colonoscopy can detect a polyp or cancer. And it can be therapeutic—we can remove a polyp before it becomes a cancer. However, it has risks. Patients have to undergo a bowel prep and anesthesia. Typically, they’ll have to take a day off work or have a loved one take off work to transport them. Noninvasive tests, which are stool studies or occult blood tests, can be easier for a patient to undergo and have less risk associated. But if they detect a polyp, a patient will need to have a colonoscopy to remove that polyp or have an investigation done.

Discover:  Moving to the challenge of implementing earlier screening: where are we at, nationally, in providing coverage for someone who is age 45 to receive a colonoscopy?

Geiger:  Since US Preventive Services Task Force issued their recommendation of age 50 in 2016, the data have changed. Multiple societies, including the ACS, have recommended moving the screening age up. It is important to have these societies reach consensus to implement change in insurance coverage or changing the standard under the Affordable Care Act, or any sort of other implementation model. So we’ve gone past awareness, but we are not quite to the implementation where younger individuals can have these tests easily. I think that will change in the next few years.

Discover:  For individuals at high-risk of colorectal cancer, there were changes in the ACS screening guidelines as well.

Geiger:  High-risk really necessitates a conversation. One of the hallmarks of colon and rectal cancer is that it can be very quiet. It may not give you a lot of symptoms. Some patients may present with rectal bleeding, blood in their stool, increase in abdominal pain, weight changes, or change in bowel functions that are not just transient. Those are indications that we need to figure out what’s going on. We need to look at that patient’s history, what symptoms they’re having, and that assessment may prompt a colonoscopy—whether it’s at age 25, 35 or 45.

Another thing to consider is family history. Patients with family members who have had colon or rectal cancer are at a higher risk, so we know that’s a higher screen. Then there are cancers that run in common with colon and rectal cancer—stomach cancer, kidney cancers, bladder cancers and uterine cancers. We also know breast cancer has some relation to colon and rectal cancer.

“The first and best treatment is catching it before it becomes a colorectal cancer.”

Discover:  With colon and rectal cancer increasing, and diagnosis hopefully catching more of those cancers at an early stage, what is happening in the landscape of treatment?

Geiger:  The first and best treatment is catching it before it becomes a colorectal cancer. If we can find and remove a polyp—a precancerous mass—then we have solved a lot of issues in terms of patients developing cancer down the road. And we actually know with the advent of colonoscopy in the ’80s, we are able to change that pathway and decrease patients’ risk of cancer if they get appropriate screening.

If they’re detected to have a colorectal cancer, then a workup ensues and we will, depending on the stage of the cancer, move patients to either surgery, chemotherapy or radiation prior to surgery. That is a very complex algorithm, and we look at location of the tumor, any lymph nodes and where the cancer may have metastasized.

Our chemotherapy drugs have significantly improved in their ability to fight off cancers. Our surgical techniques have gotten better. Our minimally-invasive techniques, whether it’s laparoscopic or robotic surgery, have gotten better. We can get many patients back to their quality of life quickly if they have been diagnosed. But again, the most effective treatment is diagnosing it before it becomes a cancer.

Discover:  Speaking of prevention, Vanderbilt is currently involved in a very exciting and ambitious project.

“We are about to launch what’s called our Colon MAP project.”

Geiger:  Vanderbilt was one of very few institutions to receive a Cancer Moonshot grant to investigate the causes of colon and rectal cancer. So we are about to launch what’s called our Colon MAP project. That project is going to look at some of the microbiome, the bacteria and organisms within our GI tract, to see if they contribute to risk factors for colon and rectal cancer.

It’s a really exciting project. We know that there are more bacterial organisms in your colon than cells in your body. Those organisms effect the health of our colon, but we poorly understand them. For the first time, we’re going to start trying to map those organisms and see if there’s a relation between them and the formation of colon and rectal cancer.

Discover:  Thank you for discussing the changes in colon and rectal cancer screening, and where we may be heading in the future.

Geiger:  Thank you.