Colorectal cancer is a cancer that starts in the rectum or colon, which is the large intestine. Both of these organs are in the lower portion of your digestive system. The colon is also known as the large intestine, and the rectum is at the end of the colon. According to the American Cancer Society (ACS), an estimated one in 20 people will develop colorectal cancer during their lifetime.
Your doctor can use staging as a guideline to figure out how far along your cancer is. It’s important for your doctor to know the stage of your cancer so they can come up with the best treatment plan for you and also so they can give you an estimate of the long-term outlook. Stage 1 of colorectal cancer is the earliest stage. The stages progress up to stage 4, which is the most advanced stage. The stages of colorectal cancer are:
- Stage I cancer penetrates the lining, or mucosa, of the colon or rectum but hasn’t spread to the organ walls.
- Stage 2 cancer has spread to the walls of the colon or rectum but hasn’t affected the lymph nodes or nearby tissues yet.
- Stage 3 cancer has moved to the lymph nodes but not to other parts of the body yet. Usually, one to three lymph nodes are involved at this stage.
- Stage 4 cancer has spread to other distant organs, such as the liver or lungs.
Colorectal cancer may not present any symptoms, especially in the early stages. If you do experience symptoms, they may include:
- changes in stool color
- changes in stool shape, such as narrowed stool
- blood in the stool
- bleeding from the rectum
- unexplained weakness
- passing excessive gas
- unintended weight loss
- abdominal cramps
- abdominal pain
If you notice any of these symptoms, make an appointment with your doctor to discuss a colon cancer screening.
Researchers don’t know what causes colorectal cancer yet. However, they do know that colorectal cancer develops when healthy cells become abnormal. The abnormal cells divide and multiply faster than they should and don’t die when they should. This leads to cell accumulation.
Abnormal cells accumulate in the lining of the colon, forming polyps, which are small, benign growths. Removing these growths through surgery is a common prevention method. Untreated polyps can become cancerous.
Sometimes, colorectal cancer occurs in family members. This is due to a gene mutation that passes from parent to child. These mutations don’t guarantee that you’ll develop colorectal cancer, but they do increase your chances.
There are some factors that may increase your risk of developing colorectal cancer:
Some factors that increase your risk of getting colorectal cancer are unavoidable. Getting older is one of them. Your chances of developing the cancer increase after you reach the age of 50. Some other unavoidable risk factors are:
- a prior history of colon polyps
- a prior history of bowel diseases
- a family history of colorectal cancer
- having a genetic syndrome, such as familial adenomatous polyposis (FAP)
- being of Eastern European Jewish or African-American descent
Some risk factors for colorectal cancer are:
- being overweight or obese
- a heavy use of alcohol
- having type 2 diabetes
- having a sedentary lifestyle
- consuming a diet high in processed foods or red meats
Early diagnosis of colorectal cancer gives you the best chance of curing your colorectal cancer. Your doctor will start by getting information about your medical and family history. They’ll also perform a physical exam. The doctor may press on your abdomen or perform a rectal exam to determine the presence of lumps or polyps.
Your doctor may run some blood tests to get a better idea of what’s causing your symptoms. Though there is no blood test that specifically checks for colorectal cancer, liver function, and complete blood count tests can rule out other diseases and disorders.
A colonoscopy involves the use of a long tube attached to a camera to examine your colon. This procedure allows your doctor to see inside your colon and rectum and note anything unusual. A colonoscopy also allows your doctor to remove tissue from abnormal areas so they can send them to a laboratory for analysis.
Your doctor may order an X-ray using a radioactive liquid called barium. Your doctor will insert this liquid into the bowels through the use of an enema. Once in place, it coats the lining of the colon and provides an outline so an X-ray can be taken.
CT scans provide your doctor with a detailed image of your colon. In the case of colorectal cancer, another name for a CT scan is a virtual colonoscopy.
Treatment of colorectal cancer depends on a variety of factors. For example, the state of your overall health and the stage of your colorectal cancer will help your doctor create an effective treatment plan.
In the earliest stages of colorectal cancer, it might be possible for your surgeon to remove cancerous polyps through surgery. During surgery, if the polyp hasn’t attached to the wall of the bowels, you’ll likely have an excellent outlook.
If your cancer has spread into your bowel walls, however, your surgeon may need to remove a portion of the colon or rectum, along with any neighboring lymph nodes. If at all possible, your surgeon will reattach the remaining healthy portion of the colon to the rectum. If this isn’t possible, they may perform a colostomy. This involves creating an opening in the abdominal wall for the removal of waste. A colostomy is usually temporary.
Chemotherapy involves the use of drugs that kill cancerous cells. In the case of colorectal cancer, chemotherapy is a common treatment after surgery to destroy any remaining cancerous cells. Chemotherapy also controls the growth of your tumor and provides symptom relief in late-stage cancer.
Radiation uses a powerful beam of energy, similar to that used in X-rays, to target and destroy cancerous cells before and after surgery. Radiation treatment commonly occurs alongside chemotherapy.
In September of 2012, the U.S. Food and Drug Administration (FDA) approved the drug Stivarga (regorafenib) to treat patients with metastatic, or late-stage, colorectal cancer that doesn’t respond to other types of treatment and has spread to other parts of the body. This drug works by blocking enzymes that promote the growth of cancer cells.
When it’s caught early, colorectal cancer is treatable and often curable. With early detection, most people live at least another five years after diagnosis. If the cancer doesn’t return in that time, you’re considered cured, especially if you’re in the first three stages of the disease. The recovery rate for stage 4 cancer has been cured in rare cases.