Genetics

Scientists are learning more about some of the inherited and acquired changes in DNA that cause cells of the colon and rectum to become cancerous. Recent discoveries of inherited genes that increase a person's risk of developing colorectal cancer are already being used in genetic tests to inform people most at risk.

Advances in understanding how these genes work are expected to eventually lead to new drugs and gene therapies to correct these gene problems. Early phases of gene therapy trials are already in progress.

Chemoprevention

Chemoprevention is the use of natural or man-made chemicals to lower a person's risk of developing cancer. Researchers are testing whether certain supplements, minerals (such as calcium), and vitamins (such as folic acid or vitamin D) can lower colorectal cancer risk.

Some studies have found that people who take multivitamins containing folic acid (also known as folate), vitamin D supplements, or calcium (through either diet or supplements) may have a lower colorectal cancer risk than people who do not. Research to clarify the possible benefits of these and other substances, such as selenium and curcumin, is now under way.

Although taking aspirin or some other non-steroidal anti-inflammatory drugs (NSAIDs) is associated with a lower risk of colorectal cancer, these drugs can cause stomach ulcers and other side effects. For this reason, taking NSAIDs specifically for this purpose is not recommended for people at average colorectal cancer risk.

NSAIDs, such as sulindac and celecoxib (Celebrex), have been shown to reduce formation of adenomatous polyps in people with familial adenomatous polyposis (FAP). The FDA has approved celecoxib for reducing polyp formation in people with FAP. However, celecoxib may have side effects such as a potential increased heart risk. You should consult with your doctor before beginning regular use of aspirin or another NSAID.

Studies indicate that a diet high in fruits and vegetables may lower colorectal cancer risk, as well as the risk of several other diseases. This hasn't been completely proven by all studies. But it is important that you eat enough servings -- at least 5 a day!

At this time, most experts recommend that people not take large doses of vitamins, minerals, or other agents unless they are part of a study or are under the advice and care of a doctor.

Earlier detection

Colorectal cancer is much easier to treat effectively if it is found at a very early stage. Studies continue to look at the effectiveness of current colorectal cancer screening methods and assess new approaches to informing the public about the importance of being screened. Less than half of Americans age 50 or older have any colorectal cancer screening at all. If everyone were tested as recommended, tens of thousands of lives could be saved each year. The American Cancer Society and other public health organizations are working to increase awareness of colorectal cancer screening among the general public and health care professionals.

Meanwhile, new imaging and lab tests are also being developed and tested. Newer, more accurate ways to look for changes in the stool that might indicate colorectal cancer have been developed. These include tests that are better able to detect blood in the stool (fecal immunochemical tests) and test that can detect changes in the DNA of cells in the stool. CT colonography (also known as virtual colonoscopy) is a special type of CT scan that can find colorectal polyps and cancers at least as accurately as a barium enema.

These tests are described in more detail in the section, "Can colorectal polyps and cancer be found early?"

Treatment

Chemotherapy: Many clinical trials are testing new chemotherapy drugs or drugs that are now used against other cancers (such as cisplatin or gemcitabine). Other studies are looking at ways to combine drugs already known to be active against colorectal cancer, such as irinotecan or oxaliplatin, to improve their effectiveness. Newer studies are also looking at adding targeted therapies such as cetuximab or bevacizumab to chemotherapy as part of adjuvant therapy. Still other studies are testing the best ways to combine chemotherapy with radiation therapy and/or immunotherapy.

Targeted therapies: Several targeted therapies are already approved for treating colorectal cancer, including bevacizumab (Avastin), cetuximab (Erbitux), and panitumumab (Vectibix). Doctors continue to study the best way to give these drugs to make them more effective.

Researchers are also studying dozens of new targeted therapies to increase the options for people with colorectal cancer. Some of these are monoclonal antibodies like the drugs listed above, while others are more like conventional drugs that are given in pill form.

Immunotherapy: Researchers are studying several vaccines to try to treat colorectal cancer or prevent it from coming back after treatment. Unlike vaccines that prevent infectious diseases, these vaccines are meant to boost the patient's immune reaction to fight colorectal cancer more effectively.

There are many types of vaccines being studied. For example, some vaccines involve removing some of the patient's own immune system cells (called dendritic cells) from the blood, exposing them in the lab to a substance that will make them attack cancer cells, and then putting them back into the body. At this time, such vaccines are only available in clinical trials.