Early signs of rectal cancer: 5 symptoms to watch

An estimated 50,000 people are diagnosed with rectal cancer each year, and the number of cases in people under the age of 40 are rising significantly. Regular screening for colorectal cancer and healthy lifestyle changes can help reduce your risk of developing the condition. 

“Colorectal cancer used to be something we associated with an older patient population, but younger patients are being diagnosed with the condition more frequently,” says Usman Shah, MD, GI medical oncologist at Atlantic Health. “A colonoscopy is an excellent screening method that can diagnose the condition early and help with rectal cancer prevention.” 

What is rectal cancer? 

Rectal cancer is a subset of colorectal cancer, which can show up anywhere along the length of your colon (large intestine). The condition often starts as a rectal polyp, which is an abnormal tissue growth, on the wall of the lowest portion of your colon. Polyps become more common as we age and, while most start out benign, there is a risk that they can grow and develop into a cancerous mass if not found and removed early.  

Rectal cancer is a form of adenocarcinoma like breast and lung cancer. It’s different from anal cancer, which is a squamous cell cancer that can be caused by infection with the HPV virus. While the two cancers can present in the same general area, they are treated differently.  

Rectal cancer signs and symptoms 

Dr. Shah explains that the five key symptoms of rectal cancer are most often found in patients under the age of 55.  

1. Blood in your stool. While seeing bright red blood with your bowel movements is most often caused by hemorrhoids, Dr. Shah says it’s also the most common symptom of rectal cancer in younger patients. Dr. Shah stresses that an examination should always be done to rule out possible colorectal cancer. 
2. Abdominal pain. This can include lower belly pain, intense pressure or cramping. 
3. Change in bowel habits. It doesn’t matter if you typically have a bowel movement every day or every three days. If you notice a persistent change in your personal bathroom routine, including constipation or diarrhea, it’s important to talk with your medical provider.  
4. Weight loss. While this symptom is less common, Dr. Shah says that if you are losing weight without trying, it could be a possible sign of rectal cancer. A loss of appetite should also be discussed with your provider.
5. Iron deficiency or anemia. Low iron levels are more common in women, especially if you’re still menstruating. However, it can also be a sign of blood loss as a result of cancer, particularly in men.  

The importance of rectal cancer screening 

The American Cancer Society recommends colorectal cancer screening for anyone 45 or older. Dr. Shah says that a colonoscopy is the gold standard for colorectal cancer screening. That’s because during the procedure your provider can see your entire colon very clearly. They can also remove any polyps they find to prevent them from growing and becoming malignant. He adds that colonoscopy is a safe procedure with a low risk of complications and is not uncomfortable.  

“The prep for a colonoscopy is probably the most inconvenient part of the entire process, but patients are asleep for the 30-minute procedure,” says Dr. Shah. “There are other screening assessment options available that use DNA testing or stool samples to identify cancer, but they don’t address or remove polyps that are present in your colon or rectum.” 

Depending on your screening results, you might not need additional testing for up to 10 years.  

Preventing rectal cancer 

While some people diagnosed with rectal cancer have a family history of the disease, most people with the condition do not. Additional risk factors include a history of chronic inflammatory bowel disease (IBD), such as ulcerative colitis or Crohn’s disease. If you have a close family member with colorectal cancer or other risk factors, Dr. Shah suggests talking to your provider to see if early screening might be right for you.  

Along with following recommended screening guidelines, a healthy diet that’s high in fiber, as well as regular exercise, can provide some protection against rectal cancer. According to the Dietary Guidelines for Americans, most adults living in the U.S. aren’t getting enough fiber. General recommendations are 25 grams per day for women and 35 grams per day for men. Dr. Shah says aiming for five to six servings of fiber each day should help you reach that goal. An example of one serving is an apple, which has around five grams of fiber.  

“Fortunately, we have a lot of actionable things we can do to reduce the risk of colorectal and rectal cancer.” says Dr. Shah. “I wish more people knew how effective screening, nutrition and exercise can be in preventing this disease or detecting it early.”