Are Bloody Stools a Symptom of Colon Cancer?

Fresh blood in stools may mean more than hemorrhoids

Roll of toilet paper
You will be spending a fair amount of time on the toilet during your colonoscopy preparation. Make sure you have proper supplies such as wet wipes, toilet paper, and a magazine. Suki Photography by Sandra Grimm/Moment/Getty Images

The color of your stools can tell you a lot about yourself. Pale, clay-colored stools might typically suggest liver dysfunction while a dark, tarry stool may lead a doctor to investigate bleeding in the upper gastrointestinal tract.

But what about a bright red, bloody stools? While this type of bleeding can be unnerving, particularly if profuse, what exactly does it tell us?

Called hematochezia, it is a condition characterized by the passage of fresh blood and is indicative bleeding in the lower gastrointestinal tract.

The most common causes are diverticulitis (inflamed pouches of the colon) and hemorrhoids (swollen veins in and around the rectum).

However, hematochezia can also be a symptom of colorectal cancer particularly in association with other tell-tale symptoms.

Hematochezia as a Symptom of Cancer

Malignant tumors tend to bleed—not profusely but enough to manifest with changes in stool color. The variations can often tell us where the bleeding is occurring.

If bleeding is in the ascending (right-side) colon, the stools will be more maroon or purple in color since the bleeding is occurring farther away from the rectum. In the case of colon cancer, it may not even result in much discoloration at all since the bleeding will more often be low to minimal.

By contract, hematochezia will result in bright red stools since the bleeding occurs in the descending (left-side) colon. If the tumor is in the rectum or toward the end of the colon, the bleeding will be fresh and more apparent.

Two other, co-occurring symptoms might suggest the presence of colorectal cancer:

Because this sort of bleeding is not usually profuse, it is often confused with hemorrhoidal bleeding.

What to Do If You Have Bright Red Stools

Hematochezia, in and of itself, is not — nor should ever be considered — an indication of colorectal cancer.

There can be so many other, more likely causes of these symptoms, even beyond the most likely suspects (hemorrhoids and diverticulitis).

Causes of bright red stools can include:

  • intestinal infections (such as bacterial enterocolitis)
  • inflammatory bowel disease (IBD)
  • recent trauma
  • abnormal growths in the lining of the colon (polyps)
  • impairment of blood supply to the colon (ischemic colitis)
  • eating beets or drinking beet juice

Whatever the cause, it is always best to call your doctor if you notice blood or any changes in the color in your stool. Avoid self-diagnosis, especially if the symptom persists.

When you do meet your doctor, be sure to advise him or her if you have a family history of cancer or anything suggestive of colon cancer.

These can include symptoms such as:

  • unintentional weight loss (occurring without dieting)
  • loss of appetite
  • nausea or vomiting
  • unexplained fatigue
  • anemia (particularly iron-deficiency anemia)
  • jaundice (the yellowing the skin and whites of the eyes)

If you experience any of these for any length of time, even a few days, see your doctor and get them checked out immediately.

As with all types of cancer, early diagnosis offers you the best opportunity for treatment success.

Sources:

Libutti, S.; Salz, L.; Willett, C., and Levine, R. “Chapter 57: Cancer of the colon.” DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 10th ed. In: DeVita VT, Lawrence TS, Rosenberg SA, eds. Philadelphia: Lippincott Williams & Wilkins; 2015.

Libutti, S.; Salz, L.; Willett, C., and Levine, R. “Chapter 60: Cancer of the rectum.” DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 10th ed. In: DeVita VT, Lawrence TS, Rosenberg SA, eds. Philadelphia: Lippincott Williams & Wilkins; 2015.

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