Colorectal Cancer
What is Colorectal Cancer?
Colorectal cancer is a disease where abnormal cells grow out of control in the colon or rectum. The colon and rectum are parts of your large intestine that help process waste before it leaves your body. This type of cancer usually starts as small growths called polyps on the inner lining of the colon or rectum. Not all polyps become cancer, but some can turn into cancer over time.
Colorectal cancer is the third most common cancer diagnosed in both men and women in the United States. It typically develops slowly over many years, which is why regular screening is so important. When caught early, before the cancer has spread, colorectal cancer is highly treatable. The five-year survival rate for localized colorectal cancer is about 90%.
Understanding your risk factors and getting screened regularly can help catch problems early. Blood tests that measure tumor markers like CEA, CA 19-9, and BRAF mutations can help monitor treatment and detect changes. These tests work best when combined with other screening methods like colonoscopy.
Symptoms
- Blood in your stool or rectal bleeding
- Persistent changes in bowel habits, including diarrhea or constipation
- A feeling that your bowel does not empty completely
- Abdominal pain, cramping, or discomfort
- Unexplained weight loss
- Weakness or fatigue
- Narrow stools that last for more than a few days
- Nausea or vomiting
Many people with early-stage colorectal cancer have no symptoms at all. This is why screening is so important, even when you feel healthy. Symptoms often appear only after the cancer has grown or spread.
Concerned about Colorectal Cancer? Check your levels.
Screen for 1,200+ health conditions
Causes and risk factors
Colorectal cancer develops when cells in the colon or rectum develop changes in their DNA. These changes cause cells to grow and divide uncontrollably. Most colorectal cancers begin as polyps, and certain types of polyps have a higher chance of becoming cancerous. Age is a major risk factor, with most cases occurring in people over 50. Family history of colorectal cancer or polyps increases your risk significantly. Inherited conditions like Lynch syndrome and familial adenomatous polyposis raise risk even further.
Lifestyle factors play a major role in colorectal cancer development. Diets high in red meat and processed meats increase risk, as do diets low in fiber and vegetables. Being overweight or obese raises your chances of developing this cancer. Smoking and heavy alcohol use are both linked to higher colorectal cancer rates. Lack of physical activity and having type 2 diabetes also contribute to increased risk. People with inflammatory bowel diseases like Crohn's disease or ulcerative colitis face elevated risk as well.
How it's diagnosed
Colorectal cancer diagnosis typically begins with screening tests like colonoscopy, which allows doctors to see inside the colon and remove polyps before they become cancerous. If cancer is suspected, a biopsy is taken during the colonoscopy to examine tissue under a microscope. Imaging tests like CT scans, MRI, or ultrasound help determine if cancer has spread to other parts of the body.
Blood tests that measure tumor markers are important tools for monitoring colorectal cancer. Rite Aid offers add-on tests including CEA, CA 19-9, and BRAF mutation testing through our Quest Diagnostics lab network. Elevated CEA levels may indicate the presence of colorectal cancer and help track treatment response. CA 19-9 can be used alongside other markers to monitor how well treatment is working. BRAF mutation testing identifies genetic changes found in about 10% of patients with metastatic colorectal cancer, which may influence treatment decisions and prognosis.
Treatment options
- Surgery to remove cancerous tissue and nearby lymph nodes, often the primary treatment for localized cancer
- Chemotherapy using drugs like fluorouracil, capecitabine, oxaliplatin, or irinotecan to kill cancer cells
- Targeted therapy drugs like bevacizumab, cetuximab, or panitumumab that attack specific cancer cell features
- Radiation therapy to shrink tumors before surgery or kill remaining cancer cells after surgery
- Immunotherapy for cancers with certain genetic markers that help the immune system fight cancer cells
- Eating a diet rich in fruits, vegetables, and whole grains while limiting red and processed meats
- Maintaining a healthy weight through regular physical activity
- Quitting smoking and limiting alcohol consumption
- Regular follow-up care and monitoring with your oncology team
Need testing for Colorectal Cancer? Add it to your panel.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
The earliest warning signs include changes in bowel habits that last more than a few days, blood in your stool, and persistent abdominal discomfort. However, early-stage colorectal cancer often causes no symptoms at all. This is why regular screening starting at age 45 is so important, even if you feel perfectly healthy.
Most health organizations recommend starting regular colorectal cancer screening at age 45 for people at average risk. If you have a family history of colorectal cancer or polyps, you may need to start screening earlier. People with inflammatory bowel disease or inherited genetic conditions should talk to their doctor about earlier and more frequent screening.
Blood tests that measure tumor markers like CEA and CA 19-9 can indicate the possible presence of colorectal cancer, but they are not used as primary screening tools. These tests are most useful for monitoring treatment response and detecting recurrence in people already diagnosed with colorectal cancer. Colonoscopy remains the gold standard for detecting colorectal cancer early.
CEA stands for carcinoembryonic antigen, a protein that can be elevated in people with colorectal cancer. The CEA test measures the level of this protein in your blood. It is primarily used to monitor treatment effectiveness and watch for cancer recurrence after treatment. Rising CEA levels may signal that cancer is growing or coming back.
A BRAF mutation test looks for a specific genetic change found in about 10% of patients with metastatic colorectal cancer. This mutation is associated with a poorer prognosis and can influence which treatments will work best. Knowing your BRAF status helps your doctor create a more personalized treatment plan for your specific cancer.
While not all colorectal cancers can be prevented, many cases are preventable through lifestyle changes and screening. Eating a high-fiber diet, exercising regularly, maintaining a healthy weight, and avoiding smoking and heavy drinking all reduce risk. Regular screening allows doctors to find and remove polyps before they become cancer.
Colorectal cancer is an umbrella term that includes both colon cancer and rectal cancer. The colon and rectum are connected parts of your large intestine. Cancers in these two areas are grouped together because they share similar characteristics and treatments, though rectal cancer may require slightly different treatment approaches.
Eating plenty of fruits, vegetables, and whole grains while limiting red and processed meats can significantly reduce your risk. Getting at least 150 minutes of moderate exercise per week helps protect against colorectal cancer. Maintaining a healthy weight, avoiding smoking, and limiting alcohol to no more than one drink per day for women or two for men also lower your risk.
Yes, you can have colorectal cancer even with normal bowel movements, especially in the early stages. Many early-stage colorectal cancers cause no symptoms at all. This is why screening is recommended for everyone starting at age 45, regardless of whether you have symptoms or bowel changes.
The frequency of tumor marker testing depends on your individual situation and treatment plan. Many doctors order CEA tests every 3 to 6 months for the first few years after treatment. Your oncologist will create a monitoring schedule based on your cancer stage, treatment type, and risk of recurrence.