Colorectal cancer symptoms

This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science

This page was reviewed on June 24, 2022.

Colorectal cancer symptoms may be minor or non-existent during the early stages of the disease, although there may be some early warning signs. The symptoms of colorectal cancer may not develop until the disease has progressed into stage 2 or beyond. Regular screening tests for cancer of the colon or rectum, especially with a colonoscopy, are recommended as part of a health plan for those over 50 years old or those under 50 who are at high risk or have a family history of the disease or other cancers. Talk with a doctor about when to start regular colorectal cancer screening

What is colorectal cancer?

Colorectal cancer is the term used to describe colon cancer and rectal cancer. Because the colon and rectum are located in the lower region of the digestive tract and have similar features, they are often grouped together. The colon stores waste and absorbs water and food, while the rectum passes waste from the body.

This article will cover:

A visual guide to early warning signs and symptoms of colorectal cancer


Early warning signs and symptoms of colorectal cancer

Most cancers in the colon or rectum develop from polyps, so screening to find and remove them when they first form helps prevent them from growing into cancers.

If early-stage colorectal cancer does cause symptoms, early warning signs may include sudden weight loss and/or narrow, ribbon-like stools. Other common early warning signs of colorectal cancer include:

  • Rectal bleeding, either bright or dark red in color
  • Narrow stools
  • Tenesmus, which is the feeling of having to empty the bowel but nothing passes
  • Anemia caused by iron deficiency
  • Persistent abdominal pain
  • Unexplained weight loss

Although these symptoms may be caused by other, less serious conditions, such as hemorrhoids, ulcers and Crohn's disease, they should be discussed with a doctor. Blood in the stool, even if it only appears intermittently, should never be ignored.

Local symptoms of colorectal cancer

Local symptoms are those that affect only the colon and/or rectum and have not spread to distant organs. Common local symptoms include:

  • Constipation
  • Diarrhea
  • Alternating diarrhea and constipation, or other changes in bowel habits
  • Rectal bleeding or blood in the stool
  • Abdominal bloating, cramps or discomfort
  • A feeling that the bowel doesn't empty completely
  • Stools that are thinner than normal

Patients who experience these possible symptoms of colorectal cancer for an extended period of time should visit a health care professional.

Systemic symptoms of colorectal cancer

Systemic colorectal cancer symptoms may impact more than the digestive tract and affect the entire body. Common systemic symptoms of colorectal cancer at all stages include:

Colon cancer symptoms

During stage 1 of colon cancer, no obvious signs or symptoms may have developed. As symptoms develop, they may vary depending on the tumor's size and location in the large intestine. Early symptoms may affect only the colon and result in changes in bowel habits. As the cancer grows, it may spread, producing systemic symptoms that affect the whole body, such as fatigue and weight loss. Some changes in bowels habits that may be considered colon cancer signs include:

  • Change in frequency of bowel movements
  • Constipation
  • Change in consistency of stool (loose or watery stools)
  • Blood in stools (either as bright red spots or dark tar-like stools)
  • Rectal bleeding
  • Abdominal pain, bloating or cramps
  • A persistent feeling of not being able to completely empty the bowels

Rectal cancer symptoms

The symptoms of rectal cancer may be similar to those of other bowel diseases, such as ulcerative colitis or Crohn's disease. But while symptoms of inflammatory bowel disease may subside during periods of remission, rectal cancer symptoms may be more severe and persistent as the cancer develops. Tumors in the rectum may change the consistency, shape or the frequency of bowel movements. Symptoms may increase and become more severe as the cancer spreads throughout the rectum or possibly into the colon. Rectal cancer signs related to bowel habits may include:

  • Diarrhea
  • Constipation
  • An inability to completely empty the bowel
  • Bloody stool
  • Change in the size or shape of stools

Metastatic colorectal cancer symptoms

Patients with metastatic colorectal cancer may not always notice symptoms before a diagnosis. Metastatic colorectal cancer symptoms may depend on the size of the tumor or tumors and where the cancer has spread outside the colon or rectum. For instance:

If the bones are affected, symptoms may include pain, fractures, constipation and/or high calcium levels.

If the lungs are affected, symptoms may include shortness of breath, difficulty breathing, coughing, pain and/or fatigue.

If the liver is affected, symptoms may include nausea, fatigue, swelling of the feet and hands, increased abdominal girth and/or jaundice.

If the lymph nodes of the abdomen are affected, it may cause bloating, a swollen belly and/or loss of appetite.

If the brain and/or spinal cord are affected, symptoms may include pain, confusion, memory loss, headache, blurred or double vision, difficulty speaking and/or seizures.

Get expert advice and care at City of Hope

Understanding when symptoms are a sign of something serious and either diagnosing the disease or confirming a previous diagnosis require expertise from specialists trained and experienced in treating colorectal cancer. At City of Hope, our experts treat all stages of colorectal cancer.

Next topic: What are the types of colorectal cancer?

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Show references
  • American Cancer Society (2020, June 29). Colorectal Cancer Signs and Symptoms.
  • Centers for Disease Control and Prevention (2021, Feb. 8). What Are the Symptoms of Colorectal Cancer?
  • American Cancer Society (2020, June 29). Can Colorectal Polyps and Cancer Be Found Early?
  • National Cancer Institute (2020, Aug. 21). Colon Cancer Treatment (PDQ®)– Patient Version.
  • U.S. National Library of Medicine. Colorectal Cancer.
  • American Cancer Society (2021, Feb. 8). Do I Have Colorectal Cancer? Signs, Symptoms, and Work-Up.
  • National Health Service (2019, Jan. 23). Complications: Ulcerative Colitis.
  • American Cancer Society (2020, June 29). Colorectal Cancer Risk Factors.