Most people don’t have signs or symptoms of colon cancer early on. By the time a patient begins noticing problems, the disease is often more advanced. That’s why it’s important to have regular colorectal cancer screenings. Screenings can detect cancer at early stages when the cure rate is high.
If you notice any of the following signs or symptoms, let your primary care provider (PCP) know:
- Weight loss for no known reason
- An ongoing bloated feeling, cramping or pain in your abdomen
- Constant tiredness and weakness
- A change in bowel habits that lasts for more than a few days, like diarrhea, constipation, narrow stools or feeling that your bowel does not empty all the way
- A feeling that you need to have a bowel movement that doesn’t go away, even after going to the bathroom
- Bright red or very dark blood in your stool or bleeding from your rectum
- Low level of red blood cells (anemia) for no known reason
Usually, these signs or symptoms are caused by other conditions, like infections, hemorrhoids or inflammatory bowel disease, not cancer. Your PCP can help you figure out what is causing your symptoms.
A Commitment to Patient Advocacy After Her Own Cancer Diagnosis
Fred Hutch Cancer Center patient Natalie Phelps seemed too young to have colorectal cancer when she started having symptoms at age 38. Her midwife and primary care provider thought there were more likely explanations. But when her discomfort continued, a gastrointestinal specialist did a colonoscopy and found a tumor.
Colon Cancer Symptoms FAQs
Colon cancer may develop slowly and go unnoticed for a long time.
“Colorectal cancer is, for the most part, a really silent disease. It takes years to progress to a point where you experience symptoms,” said Rachel Issaka, MD, MAS, a Fred Hutch gastroenterologist. To find colon cancer earlier, before you have any reason to be concerned, get screened.
Your health care provider will ask you about your symptoms, your health history and your family history. They’ll also ask about factors that might put you at risk for colon cancer or other conditions that might cause the same symptoms. They’ll examine you to check for clues about what’s been bothering you. For example, they may press on your belly to feel your organs or check for unusual lumps. They may do a digital rectal exam. In this exam, they feel inside your rectum with a gloved, lubricated finger to check for anything out of the ordinary.
Based on your conversation and exam, your provider may order tests to get more information. These could include stool tests to check for blood, blood tests to check for tumor markers or other signs of illness, a colonoscopy or other tests. A colonoscopy lets physicians see the inside of your colon and take samples of tissue for testing. If the provider is concerned you might have colon cancer, they’ll ask for a biopsy. In a biopsy, a pathologist looks at a tissue sample under a microscope to check for signs of cancer.
Medical tests can sometimes lead to either false-positive or false-negative results. In cancer diagnosis:
- A false positive means the test shows cancer is present when it really isn’t. If you get a false positive, it can cause anxiety and lead you to have more tests, which have their own risks.
A false negative means the test shows there’s no cancer even though there is. If you get a false negative, you might delay getting treatment. (Adapted from the National Cancer Institute.)
Colon polyps are usually benign (not cancer), and they don’t typically cause any symptoms. But they sometimes cause blood in the stool or bleeding from the rectum. Over time, some polyps may turn into cancer. As the cancer cells multiply, they can form a tumor, grow through the colon wall and spread outside the colon, affecting other parts of the body. This process can cause colon cancer symptoms.