Bleeding from colon cancer can appear as bright red blood (from lower colon/rectum) or dark, black, tarry stools (from higher up in the colon), or sometimes no visible blood (occult), causing anemia over time; the color depends on the bleeding's location in the digestive tract, with lower tumors usually causing red blood and higher ones causing black, tarry blood.
Blood from lower down in your colon or rectum is usually red. Bleeding from higher up in the colon can make stools look black. Skinny or thin stool. A sudden change to ribbon-thin or pencil-thin stool might happen if cancer is making the passage smaller.
There are often no symptoms in the early stages of the disease. The most common symptoms of bowel cancer are: blood in the stools; this might be bright red if the bleeding is in the rectum, or might make the stools look dark brown or black if the bleeding is somewhere else in the digestive tract.
Blood from higher up in the bowel doesn't look bright red. It goes dark red or black and can make your poo look like tar.
Bright red blood in the stool typically indicates that there is bleeding in the rectum or colon, which may be a sign of colon or rectal cancer. Rectal bleeding can also be caused by hemorrhoids.
Bright red blood in your stool might be more alarming because it suggests active bleeding. Darker blood usually suggests older bleeding that's not active anymore. But darker blood in your stool can be deceiving. It doesn't always mean the bleeding has stopped, only that it's coming from someplace higher up.
Colorectal Cancer Symptoms
Bleeding from the bottom is sometimes a sign of bowel cancer. This is easier to treat if it's found early, so it's important to get it checked.
Blood tests aren't used to diagnose colon cancer. But blood tests can give clues about overall health, such as how well the kidneys and liver are working. A blood test might be used to look for a low level of red blood cells. This result might indicate that a colon cancer is causing bleeding.
The signs of bleeding in the digestive tract depend upon the site and severity of bleeding. If blood is coming from the rectum or the lower colon, bright red blood will coat or mix with the stool. The cause of bleeding may not be serious, but locating the source of bleeding is important.
A number of patients with colon cancer have been misdiagnosed with inflammatory bowel diseases (IBD) such as irritable bowel syndrome, diverticulitis, and colitis. Other conditions such as hemorrhoids may also be misdiagnosed. Likewise, patients with these conditions may be misdiagnosed as having colon cancer.
Symptomatology by Tumor Location
Right-sided tumors more often presented with abdominal pain, upper gastrointestinal symptoms, anemia, and anorexia, while left-sided tumors more often presented with rectal pain, rectal bleeding, and “hemorrhoid” complaints (all p<0.01).
Different types of bleeding:
Here are the main differences: Hemorrhoid bleeding is usually bright red and occurs during or after a bowel movement. Colorectal cancer bleeding can be either dark or bright red and can occur at any time. Anal cancer can cause bright red, black, or tarry bleeding and can occur at any time.
If you experience any of the common colon cancer symptoms, even if they come and go, it's crucial to consult with a healthcare provider. Some symptoms that should not be ignored include: Persistent changes in bowel habits lasting more than a few days. Blood in the stool, even if it occurs infrequently.
Watch out for the following:
Most colorectal cancers start as a growth on the inner lining of the colon or rectum. These growths are called polyps. Polyps are quite common, especially as you get older. Most polyps are benign, or noncancerous.
Colonoscopy. In this test, the rectum and entire colon are examined using a colonoscope, a flexible lighted tube with a lens for viewing and a tool for removing tissue, which is inserted through the anus into the rectum. During colonoscopy, any abnormal growths in the entire colon and the rectum can be removed.
Bleeding Types & Severity – Bleeding (haemorrhage) can be external or internal, ranging from minor cuts to life-threatening arterial bleeds; arterial bleeding is bright red, fast, and requires immediate medical attention if major arteries are involved.
The shade of red depends on how much oxygen it carries. Oxygen-rich blood (found in your arteries) is a bright, cherry-red color. This is the blood pumped from your lungs and heart to the rest of your body. Oxygen-poor blood (found in your veins) is a darker, maroon-red color.
“Bright red blood might be from something low in the colon or rectum, like diverticulosis or hemorrhoids,” says Richards. “Darker blood may be from something higher up. If the blood is black or tar-like, that could signal an issue with the small intestine or stomach.”
If you notice bright red blood when you have a bowel movement, it's likely coming from a source in your colon or rectum. “Bright red blood can point to an internal or external hemorrhoid, fissure, inflammatory bowel diseases—like ulcerative colitis or Crohn's disease—or even colon cancer,” says gastroenterologist Dr.
Rectal bleeding may show up as blood in your stool, on the toilet paper or in the toilet bowl. Blood that results from rectal bleeding is usually bright red in color, but occasionally can be dark maroon.
That said, specific stool characteristics are common with colon cancer, including: Narrow, pencil-thin stools caused by material having to squeeze past an obstruction. Hard pebbles or nuggets that occur because of cancer-related constipation cause waste to remain in the colon longer and have more water removed from it.
Symptoms