Jeffrey Meyerhardt, MD, MPH, FASCO, is the Clinical Director and Senior Physician at the Gastrointestinal Cancer Center at the Dana-Farber Cancer Institute (DFCI) and Associate Professor of Medicine at Harvard Medical School. He is the Cancer.Net Associate Editor for gastrointestinal cancers.
Colorectal cancer is the 4th most common cancer diagnosed in the United States each year. It affects men and women. It affects people with a family history of colorectal cancer and people with absolutely no prior family history. It affects young people and older people.
While there are risk factors for developing colorectal cancer, those risk factors are relative. For example, obesity can increase the risk of developing colorectal cancer over one’s lifetime, but average-weight people can also develop it. Physically active people have a lower risk of developing this cancer, but there are still marathon runners and triathletes who are also diagnosed.
All cancers that start in an organ in the body should be staged at diagnosis. The treatment plan is based on the stage of colorectal cancer. Staging is a way of describing where the cancer is located, if or where it has spread, and whether it is affecting other parts of the body.
Staging for colorectal cancer includes imaging scans of your chest, abdomen, and pelvis. Those images are looking for disease outside the colon and rectum. Sometimes imaging can’t find cancer that has spread to other parts of the body. This is because imaging scans can’t see microscopic cells. So even if your liver, for example, looks like it does not contain cancer on a scan, there may be small pockets of cells that the scan won’t find. Some patients may be given treatments in addition to surgery, like chemotherapy and/or radiation therapy, with the goal of destroying these microscopic cells.
There are 2 parts of staging that are important for predicting whether there’s a chance that other pockets of cancer cells are elsewhere in your body. These are the “T” and “N” elements of staging.
In colorectal cancer, the size of the cancer is not relevant. What’s important to know is how far the tumor has gone through the bowel wall. This is the “T” part of staging, also called the “depth of invasion.” It is also important to know if any lymph nodes around the tumor are involved. This is the “N” part of staging.
We can only know the T and N parts of the staging after you have surgery for the colon cancer. The surgeon will send all of the tissues removed during surgery to a pathologist, who will then determine how many layers of the bowel wall the tumor went through (T stage). The pathologist will also determine whether lymph nodes were involved and, if so, how many (N stage). Knowing the T and N of the stage can help predict the chance that there could be microscopic disease elsewhere.
In rectal cancer, magnetic resonance imaging (MRI) or an endoscopic ultrasound will be done to determine the T and N stage. Based on that information, some people with rectal cancer may receive chemotherapy, radiation therapy, or both before surgery.
If the cancer has not visibly spread when it is diagnosed, the cancer’s stage will also determine if chemotherapy should be given to reduce risk of the cancer coming back, called “recurrence.”
The stage is a very important part of cancer treatment. Be sure to ask your doctor what the cancer’s stage is.
Cancers arise when something goes wrong in regular cells, and these cells are now not growing as they should in the body. The “something” that went wrong is often a series of mutations, or changes in the genes in that cell. Molecular testing is done to learn which mutations occurred in the colorectal cells that turned into cancer. Testing the tumor to find out what mutations occurred may impact treatment decisions. This testing is different from genetic testing, which is testing your overall body’s chance of developing certain diseases, including cancers.
Currently, testing is usually only done if you have metastatic cancer. The tumor should be sent for a panel of tests that will look for different mutations. At this time, much of what is found will not guide treatment decisions for the cancer, but there are some mutations that, if found, will affect the treatment plan, such as a RAS or BRAF mutation.
Molecular testing results mostly will not change treatment decisions for those with non-metastatic colorectal cancer, although testing for something called “microsatellite instability” can help find genetic risks in all people with colorectal cancer. Regardless of your stage, it is important to ask your doctor if your tumor was tested or is being tested.
In general, we know a lot about managing the side effects of chemotherapy used to treat colorectal cancer. We know what the side effects of chemotherapy are, how much chemotherapy to give so side effects can be managed, and what medications can be used to help with (and ideally prevent) side effects. That being said, everyone’s bodies are different, and people react differently to the same drugs. Ask your health care team what side effects are common, which ones are less common, and how to manage side effects.
There are other treatments used to treat colorectal cancer, including radiation therapy and targeted therapy. These have their own specific side effects, and it is just as important to ask which side effects are common, which are less common, and how they can be managed.
Knowing who to call if a side effect happens is one of the most important things for patients to know, especially if the side effect has not been controlled with medication already provided by the health care team. Remember that you may not know if something happening to you is a side effect or not. I think a good principle to keep in mind is that if something feels different or wrong, you should contact your oncology team to get it checked out.
There is no one answer or approach to this question. Every patient’s situation is different, and everyone copes with cancer differently. Know that cancer care is a team effort. This team may include your doctor, a nurse practitioner (NP) or physician assistant (PA), infusion nurses, oncology nurses, a social worker, a dietitian, a financial counselor, a complementary medicine provider, clinic assistants, office staff, and many others. Not all offices will have all of these team members, and not all people will need all of these specialties.
When it comes to getting the support you need, discuss with your oncologist:
What available services can be part of your team
Who the doctor thinks should be involved now
How to access other support members, if needed in the future
For many people, the internet is the first place they go to learn more about their diagnosis and treatment. It’s important to know that you’re getting reliable information from the internet, and Cancer.Net is one of those reliable sources. There are also several advocacy groups that support people with colorectal cancer, including Fight Colorectal Cancer and the Colorectal Cancer Alliance.
Know that you should not be going through this alone. Your team will know how to guide you and support you. Just make sure your team is right for your situation.