Colorectal cancer is a cancer that starts in the rectum or colon. Both of these organs are in the lower portion of your digestive system. The colon is also known as the large intestine. The rectum is at the end of the colon.
The American Cancer Society estimates 1 in 22 men and 1 in 24 women will develop colorectal cancer during their lifetime.
Your doctor may use staging as a guideline to figure out how far along the cancer is. It’s important for your doctor to know the stage of the cancer so they can come up with the best treatment plan for you and give you an estimate of your long-term outlook.
Stage 1 colorectal cancer is the earliest stage. The stages progress up to stage 4, which is the most advanced stage. Here are the stages of colorectal cancer:
- Stage 1. The cancer has penetrated the lining, or mucosa, of the colon or rectum but hasn’t spread to the organ walls.
- Stage 2. The cancer has spread to the walls of the colon or rectum but hasn’t affected the lymph nodes or nearby tissues yet.
- Stage 3. The 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. The 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 getting a colon cancer screening.
Researchers are still studying the causes of colorectal cancer. While there’s a growing list of risk factors, they act alone or in combination to increase one’s risk for developing colorectal cancer.
Abnormal cells accumulate in the lining of the colon, forming polyps. These are small, benign growths. Removing these growths through surgery is a common preventive 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 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 developing colorectal cancer are unavoidable and can’t be changed. Age is one of them. Your chances of developing this 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 descent
Other risk factors are avoidable. This means you can change them to decrease your risk of developing colorectal cancer. Avoidable risk factors include:
- 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
An early diagnosis of colorectal cancer gives you the best chance of curing it. Your doctor will start by getting information about your medical and family history. They’ll also perform a physical exam. They 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’s no blood test that specifically checks for colorectal cancer, liver function tests and complete blood count tests can rule out other diseases and disorders.
A colonoscopy involves the use of a long tube with a small, attached camera. This procedure allows your doctor to see inside your colon and rectum to check for anything unusual. During a colonoscopy, your doctor can also remove tissue from abnormal areas. These tissue samples can then be sent to a laboratory for analysis.
Your doctor may order an X-ray using a radioactive contrast solution that contains the metallic element barium. Your doctor will insert this liquid into the bowels through the use of an enema. Once in place, the barium solution coats the lining of the colon. This helps improve the quality of the X-ray images.
CT scans provide your doctor with a detailed image of your colon. When used in diagnosing colorectal cancer, another name for a CT scan is a virtual colonoscopy.
Treatment of colorectal cancer depends on a variety of factors. The state of your overall health and the stage of your colorectal cancer will help your doctor create a treatment plan.
In the earliest stages of colorectal cancer, it might be possible for your surgeon to remove cancerous polyps through 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, 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 may be temporary or permanent.
Chemotherapy involves the use of drugs to kill cancer 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.
While chemotherapy provides some symptom relief in late-stage cancer, it often comes with side effects that need to be controlled with additional medication.
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 therapy commonly occurs alongside chemotherapy.
In September 2012, the U.S. Food and Drug Administration approved the drug regorafenib (Stivarga) to treat 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.