What are the Signs of Colon Cancer?
Colorectal cancer refers to cancer that develops in either the colon or rectum. Colon cancer begins in the large intestine, while rectal cancer develops in the rectum, the final several inches of the digestive tract.
Colorectal cancer often begins as a growth called a polyp. Some types of polyps, particularly adenomatous polyps, can become cancerous over time. Screening can find these precancerous growths so they can be removed before cancer develops. Screening can also detect colorectal cancer at an earlier stage, when treatment is often more successful.
But what are the signs of colon cancer? And when should you talk with a doctor?
What Are the Signs and Symptoms of Colon Cancer?
Colorectal cancer does not always cause symptoms, especially in its early stages. That’s one reason regular screening is so important—even if you feel completely healthy.
When symptoms do occur, they may include:
- A persistent change in bowel habits, including diarrhea or constipation
- A change in the size or shape of your stool, such as narrower stools
- A feeling that your bowel does not completely empty
- Rectal bleeding or blood in the stool
- Abdominal cramping, pain, bloating, or discomfort
- Weakness or fatigue
- Unexplained weight loss
- Changes in appetite
These symptoms can have many causes other than colorectal cancer, including hemorrhoids, infections, irritable bowel syndrome, and inflammatory bowel disease. However, new or persistent symptoms should be evaluated by a healthcare professional rather than assumed to be harmless.
Don't Ignore Blood in Your Stool
Seeing blood in your stool does not necessarily mean you have colon cancer. Hemorrhoids, anal fissures, inflammatory bowel disease, diverticular disease, polyps, and other conditions can also cause gastrointestinal bleeding.
However, blood in the stool should not simply be attributed to hemorrhoids without discussing it with a healthcare professional. The color of the blood can vary, and some gastrointestinal bleeding may not be visible at all.
If you notice rectal bleeding, dark or bloody stools, or a persistent change in your bowel habits, contact your doctor so the underlying cause can be determined.
Can You Have Colon Cancer Without Symptoms?
Yes.
In fact, colorectal cancer may not cause noticeable symptoms until it has grown or spread. That’s why waiting until you notice a problem is not an effective colorectal cancer prevention strategy.
Screening is designed to find colorectal cancer before symptoms develop. It can also find precancerous polyps and allow them to be removed before they become cancer.
This is one of the most important messages behind Digestive Healthcare Center’s Colon Cancer Prevention Program: you don’t have to wait for symptoms to take action.
Who Is at Risk for Colon Cancer?
Age is an important risk factor, but colorectal cancer can affect adults younger than 50 as well.
Other factors that can increase colorectal cancer risk include:
- A personal history of colorectal cancer or certain types of polyps
- A family history of colorectal cancer or polyps
- Inflammatory bowel disease, including Crohn’s disease and ulcerative colitis
- Certain inherited genetic conditions, including Lynch syndrome and familial adenomatous polyposis
- Overweight or obesity
- Physical inactivity
- Smoking
- Alcohol use
Having a close relative with colorectal cancer can be particularly important when determining when screening should begin. People with a strong family history or other risk factors may need to begin screening earlier or follow a different screening schedule than people at average risk.
If you are concerned about your family history, talk with a gastroenterologist about your individual risk rather than relying on the standard screening age alone.
When Should You Start Colon Cancer Screening?
For adults at average risk, current guidelines recommend beginning regular colorectal cancer screening at age 45.
The U.S. Preventive Services Task Force recommends screening average-risk adults ages 45 to 75. For adults ages 76 to 85, the decision to continue screening should be individualized based on overall health, previous screening history, and personal preferences.
The American Cancer Society‘s current 2026 guideline likewise recommends that average-risk adults begin screening at age 45 and continue through age 75 when they are in good health and have a life expectancy of more than 10 years. For adults ages 76 to 85, screening should be discussed with a healthcare provider.
Importantly, these recommendations apply to people without symptoms and who are considered average risk. If you have symptoms that could indicate colorectal cancer, you should talk with a healthcare professional regardless of your age.
What Tests Are Used to Screen for Colon Cancer?
There isn’t just one way to screen for colorectal cancer. Several screening options are recommended for average-risk adults.
Depending on your age, risk factors, medical history, and preferences, your doctor may recommend:
- Colonoscopy
- Fecal immunochemical testing (FIT)
- High-sensitivity guaiac-based fecal occult blood testing
- Stool DNA-FIT testing
- CT colonography, sometimes called a virtual colonoscopy
- Flexible sigmoidoscopy
The USPSTF recommends colonoscopy every 10 years when it is selected as the screening method, while FIT is performed annually and stool DNA-FIT is performed every 1 to 3 years. CT colonography is recommended every 5 years.
The American Cancer Society also emphasizes that offering patients multiple screening options can help improve participation because the most effective screening test is ultimately the one a person completes.
How Does a Colonoscopy Help Prevent Colon Cancer?
Colonoscopy is different from many other screening tests because your gastroenterologist can examine the lining of the entire colon and rectum and, when appropriate, remove polyps during the same procedure.
If a precancerous polyp is found, removing it can prevent that polyp from developing into colorectal cancer. If cancer is found, detecting it through screening can allow treatment to begin earlier.
Before a colonoscopy, the colon must be adequately cleaned so the physician can see the lining clearly. Your gastroenterology practice will provide specific bowel-preparation instructions based on your individual needs.
What Happens If a Screening Test Is Abnormal?
A positive stool-based screening test does not mean that you have colon cancer.
However, an abnormal result needs appropriate follow-up. According to current screening recommendations, a positive stool-based screening test should be followed by a timely colonoscopy so the cause of the abnormal result can be evaluated.
If you have symptoms such as rectal bleeding or a persistent change in bowel habits, your doctor may recommend diagnostic testing rather than routine screening.
Can You Reduce Your Risk of Colon Cancer?
Screening is one of the most effective ways to prevent colorectal cancer or find it early, but lifestyle choices can also influence your risk.
Steps that may help lower your risk include:
- Staying physically active
- Maintaining a healthy weight
- Eating a diet rich in vegetables, fruits, whole grains, and other plant foods
- Limiting red and processed meat
- Avoiding tobacco
- Limiting or avoiding alcohol
These steps can support overall health while potentially reducing colorectal cancer risk.
However, even people who eat well, exercise, and have no obvious risk factors can develop colorectal cancer. That’s why keeping up with recommended screening remains so important.
Don't Wait for Symptoms to Get Screened
One of the biggest misconceptions about colon cancer is that you only need a colonoscopy or another screening test if something feels wrong.
In fact, screening is intended for people who don’t have symptoms.
Screening is intended for people who don’t have symptoms. It can identify colorectal cancer earlier and, in some cases, prevent cancer altogether by finding and removing precancerous polyps.
If you’re 45 or older and haven’t started colorectal cancer screening, now is the time to talk with a gastroenterologist about your options. If you have a family history of colorectal cancer or polyps, inflammatory bowel disease, or another risk factor, you may need to begin screening earlier.
And if you’re experiencing rectal bleeding, blood in your stool, unexplained weight loss, persistent changes in bowel habits, abdominal pain, or unusual fatigue, don’t wait for your next routine screening appointment. Contact Digestive Healthcare Center today to determine whether further evaluation is needed.
Colon Cancer Specialists in New Jersey
At Digestive Healthcare Center, our gastroenterologists help patients throughout Hillsborough, Somerville, Warren, and surrounding New Jersey communities understand their colorectal cancer risk and stay current with appropriate screening.
Through our Colon Cancer Prevention Program, we are committed to helping patients take proactive steps toward colorectal cancer prevention and early detection.
Whether you need your first screening, have questions about which screening option is right for you, or are experiencing symptoms that concern you, our team is here to help.
Don’t wait for symptoms to take your colorectal health seriously. Contact Digestive Healthcare Center today to schedule an appointment with one of our experienced gastroenterologists.
Make an Appointment for Comprehensive Digestive Care in NJ
At Digestive Healthcare Center, we want each patient at our three offices in New Jersey to feel confident about their digestive health. We encourage you to contact us today to make an appointment with one of our expert gastroenterologists – don’t wait to start putting your digestive health first!
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