What’s New in Colorectal Cancer Research?

Research is always going on in the area of colorectal cancer. Scientists are looking for causes and ways to prevent colorectal cancer, better ways to find it early (when it's small and easier to treat), and ways to improve treatments. Here are some examples of current research.

Reducing colorectal cancer risk

Many studies are looking to identify the causes of colorectal cancer. The hope is that this might lead to new ways to help prevent it.

Some studies are looking to see if certain types of diets, dietary supplements, or medicines can lower a person’s risk of colorectal cancer. For example, many studies have shown that aspirin and pain relievers like it might help lower the risk of colorectal cancer, but these drugs can have serious side effects. Researchers are now trying to figure out if the benefits might outweigh the risks for certain groups of people at high colorectal cancer risk.

Finding colorectal cancer early

Doctors are looking for better ways to find colorectal cancer early by studying new types of screening tests (like blood tests) and improving the ones already being used. Researchers are also trying to figure out if there's any test or screening plan that clearly works best.

They're also looking for ways to educate and encourage people to get the routine screening tests that are available today and known to help reduce the number of deaths from this cancer.

Testing colorectal cancer cells

Not all colorectal cancers are the same. Researchers are trying to identify some of the differences between colorectal cancers based on things like the gene or protein changes in the cancer cells. This might lead to better understanding of how colorectal cancer grows and spreads. It might also help determine which cancers are more likely to be helped by certain treatments, as well as which ones are more likely to come back after treatment.

Molecular tests to help plan treatment

In some colorectal cancers, the cancer cells have changes in certain genes or proteins that might affect how they grow, as well as how well they might respond to certain cancer medicines.

When colorectal cancer has been found, lab tests are now routinely done on the cancer cells to look for certain gene or protein changes, which are sometimes referred to as biomarkers. The results of biomarker testing might affect a person’s treatment options by showing if certain medicines are (or are not) likely to be helpful. Several biomarkers are now routinely tested for (see Tests to Diagnose and Stage Colorectal Cancer), and many others are now being studied to see if they might help improve colorectal cancer treatment.

Tests to look for cancer cells or DNA in the blood

Researchers have found that the blood of people with colorectal cancer often contains cancer cells as well as pieces of DNA from the cancer. Removing blood and testing it for cancer (cells or DNA) is sometimes referred to as a liquid biopsy.

Researchers are now studying whether liquid biopsy samples can be tested for specific gene or protein changes to help guide treatment, in the same way that tumor samples are tested for these biomarkers. This type of testing might be useful in some situations because it is usually much easier to get a blood sample than to remove a piece of tumor for testing.

Testing the blood for tumor cells or DNA could have other uses as well. For example, some newer tests look for circulating tumor DNA (ctDNA) in a patient’s blood. This type of testing might be helpful in certain situations, such as after surgery to see if any cancer cells might have been left behind (and therefore more treatment might be needed). Research is under way to see how helpful these tests are. Some ctDNA tests are already available, although not all doctors agree on how useful they are at this time.

Researchers are also studying if ctDNA testing might be helpful after treatment is complete, to look for possible signs that the cancer has come back (recurred). The hope is that this type of testing might be able to detect a recurrence earlier than imaging tests (such as CT scans) or other tests could.

Treating colorectal cancer

Researchers are always looking for better ways to treat colorectal cancer.

Surgery

Surgeons continue to improve the operations used for colorectal cancers. Rectal cancer surgery done through the anus, without cutting the skin, is also being studied.

Organ preservation -- keeping your body working the way it normally does -- is another research goal. For instance, doctors are looking at the ideal timing of surgery after chemo is used to shrink a rectal tumor and how to know when they've got the best response in each patient.

Sometimes when colorectal cancer recurs (comes back), it spreads to the peritoneum (the thin lining of the abdominal cavity and organs inside the abdomen). These cancers are often hard to treat. Surgeons have been studying a procedure called hyperthermic intraperitoneal chemotherapy (HIPEC). First, surgery is done to remove as much of the cancer in the belly as possible. Then, while still in the operating room, the abdominal cavity is bathed in heated chemotherapy drugs. This puts the chemo right in contact with the cancer cells, and the heat is thought to help the drugs work better. Some patients are living longer with this type of treatment, but more studies are needed to know which patients it can help. This type of treatment also requires doctors and nurses with special training and specialized equipment, so it's not widely available. 

For colorectal cancer that has spread to the liver and can’t be removed by surgery, another procedure being studied is hepatic arterial infusion chemotherapy (HAIC).  In this procedure, surgery is done to implant a pump or port (similar to a port for IV chemo but larger) close to the hepatic artery, which is the blood vessel feeding most cancers in the liver. The doctor can then put chemo into the pump, which is released directly into the liver and helps kill the cancer cells while leaving healthy liver cells unharmed. Often, HAIC is given along with systemic chemo (chemotherapy given through a vein or central venous catheter). More research is being done to find out which patients are the best candidates for this procedure. Currently it can only be done in facilities that are experienced.

Chemotherapy

Chemotherapy is an important part of treatment for many people with colorectal cancer, and doctors are constantly trying to make it more effective and safer. Different approaches are being tested in clinical trials, including:

• Testing new chemo drugs or drugs that are already used against other cancers.
• Looking for new ways to combine drugs already known to work against colorectal cancer to see if they work better together.
• Studying the best ways to combine chemotherapy with radiation therapy, targeted therapies, and/or immunotherapy.

Better ways to identify, prevent, and treat chemo side effects are other areas of research interest.

Targeted therapy

Targeted therapy drugs work differently from standard chemotherapy drugs. They affect specific parts of cancer cells that make them different from normal cells. Several targeted therapy drugs are already used to treat advanced colorectal cancer. Researchers are studying the best way to give these drugs, as well as looking for new targeted drugs.

Most advanced colorectal cancers that have spread are now tested for mutations (changes) in certain genes (or changes in the proteins they code for) to see if targeted drugs might be an option for treatment. To learn more, see Tests to Diagnose and Stage Colorectal Cancer.