What are the symptoms of colorectal cancer?

Female doctor shakes hands with patient to offer love, concern and encouragement.


Identify colon cancer and rectal cancer symptoms early to know when to see your doctor.


By Dr. Pranat Kumar, Colorectal Surgery, Director of Rectal Cancer Program, Vassar Brothers Medical Center, part of Nuvance Health


If talking about digestive problems gives you a stomachache, you are not alone! While it can be difficult to share details about changes in your bowel habits or blood in your stool, it is vitally important to tell your doctor. While there are many reasons why you might experience these symptoms, it is worth investigating right away because colorectal cancer is one of them.



Understanding colorectal cancer


Everyone needs to know the signs of colorectal cancer because it is the third most common cancer diagnosed in people in the United States, it usually does not cause symptoms until it is advanced and may be more difficult to treat, and it is increasing in people under age 50. 


The good news is colorectal cancer can be prevented through regular colonoscopy screenings. The United States Preventive Services Task Force (USPSTF) recommends people at average risk of colorectal cancer start screenings at age 45.


If you are younger than 45, or older than 45 but do not get regular screening colonoscopies, it is especially important for you to pay attention to possible signs of colorectal cancer. While colorectal cancer can occur in anyone at any age, it is also important for those with risk factors to be particularly aware of colorectal symptoms.



Colorectal cancer risk factors include being older than age 50, personal or family history of cancer, and lifestyle habits such as eating an unhealthy diet, not exercising, smoking tobacco, or drinking alcohol in excess. 



What are signs of colorectal cancer?


Colorectal cancer refers to either colon cancer or rectal cancer. While it is important to know the signs of colorectal cancer, some other health conditions can also cause these gastrointestinal symptoms.


Try not to panic, but you should see your doctor if you have symptoms that are unusual for you and do not go away within several days. See your doctor right away if you have severe pain or blood in your stool.


Here are common symptoms of colorectal cancer:


  • A change in bowel habits

  • Blood in your stool

  • Diarrhea, constipation or feeling that the bowel does not empty all the way

  • Abdominal pain, aches or cramps that do not go away

  • Unexplained weight loss


One or many of these symptoms can occur if someone has colorectal cancer. Your doctor may err on the side of caution if you have one or two symptoms and order tests to see what might be causing them. If you are experiencing many or all these symptoms at the same time, your doctor may be more concerned about colorectal cancer.



What is the most common symptom of colorectal cancer?


Dark red blood in the stool and changes in bowel habits usually occur before abdominal pain and weight loss. Hemorrhoids, fissures and polyps can also cause blood in your stool, but it is usually bright red. See your doctor if you have blood in your stool and be prepared to talk about what it looks like, how often it occurs, any recent diet changes, and your personal and family health history.


Does colorectal cancer always cause symptoms?


In early stages, colorectal cancer usually does not cause symptoms. That is why colonoscopy screenings are so important. During a colonoscopy screening, a gastroenterologist or colorectal surgeon can remove precancerous polyps before they might turn into cancer. They can also identify cancer early before it causes symptoms and when it might be more treatable. Prevention is key, but early detection is also critical to having a positive outcome.


What should I do if I have symptoms of colorectal cancer?


Some signs of colorectal cancer can be symptoms of another medical condition. It is usually best for you to discuss your symptoms first with your primary care provider who can then order tests and connect you with the appropriate specialist, such as a gastroenterologist.



If your primary care provider suggests you have a colonoscopy, you will first meet with a gastroenterology specialist. They will likely recommend you have a colonoscopy to check your large intestine. Usually, a gastroenterologist or colorectal surgeon will identify colorectal cancer during a diagnostic colonoscopy.





The bottom line: While colorectal cancer is more common in people over age 50, anyone at any age can get colon cancer or rectal cancer. See your primary care provider if you have colorectal cancer symptoms, including blood in the stool and changes in bowel habits. While colorectal cancer symptoms are similar to signs of other digestive tract conditions, do not delay seeing your doctor because early detection of any medical condition — especially cancer — is a crucial step to having a positive outcome.