Do Stomach or Colon Cancers Always Cause Blood in Stool?

I have a question?

I would like to ask the doctor...
Is it true that stomach cancer or colon cancer always presents with blood in the stool? If there is bleeding in the stomach or intestines, is it always blood in every bowel movement, or can it be intermittent? A few days ago, I felt some discomfort in my abdomen, but there was no pain, and my appetite was smaller.
I had two bowel movements that were somewhat loose, but I couldn't confirm if there was blood in them...
They weren't bright red until the morning of the day before yesterday when I had diarrhea (stool + water + quite a bit of gas)...
The color was similar to yellow, not red at all, and then I went to see a doctor.
After taking medication, I felt better! ((I have had blood in my stool twice before, but I didn't pay attention to it and it resolved on its own; I thought it was hemorrhoids.
Does this count as blood in the stool?? Is it a sign of stomach or colon cancer??)) PS.
Thank you for your response.

Hai, 20~29 year old female. Ask Date: 2004/09/28

Dr. Chen Zhiping reply Gastroenterology and Hepatology

Hello, the presence of blood in the stool does not necessarily indicate gastric or colorectal cancer.
If there is gastrointestinal bleeding from the upper digestive tract, the stool is typically black or dark red.
In contrast, if the bleeding originates from the lower digestive tract, the stool may appear bright red.
If you notice fresh blood after a bowel movement or on the stool, it may be related to issues with the anus or rectum.
However, to understand the cause and rule out the possibility of cancer, it is essential for you to visit a gastroenterologist or colorectal surgeon for further examination.
Thank you, Dr.
Chen Chi-Ping, Internal Medicine.

Reply Date: 2004/09/28

More Info

When it comes to stomach or colon cancers, it is important to understand that not all cases will present with blood in the stool. The presence of blood can vary significantly depending on the location and severity of the bleeding within the gastrointestinal tract.
In general, if there is bleeding from the upper gastrointestinal tract, such as from the stomach or duodenum, the blood may appear as black or tarry stools, known as melena. This occurs because the blood has been digested as it passes through the intestines. Conversely, bleeding from the lower gastrointestinal tract, such as from the colon or rectum, typically results in bright red blood, which may be seen on the stool or on toilet paper.

Regarding your question about whether blood in the stool is always present with stomach or colon cancer, the answer is no. Many patients with these types of cancers may not experience any visible blood in their stools. Symptoms can vary widely, and some individuals may present with other signs such as weight loss, changes in bowel habits, abdominal pain, or unexplained fatigue.
In your case, you mentioned experiencing episodes of loose stools and some discomfort, but you were unsure if you had blood in your stool. It is crucial to differentiate between actual blood and other substances that may resemble blood, such as food particles or substances from your diet. For instance, certain foods, particularly those that are red or dark in color, can sometimes cause the stool to appear discolored, which may lead to confusion regarding the presence of blood.

You also mentioned having experienced blood in your stool in the past, which you attributed to hemorrhoids. Hemorrhoids are a common cause of bright red blood in the stool and can occur due to straining during bowel movements, constipation, or other factors. If you have had episodes of blood in your stool that resolved on their own, it is possible that these were related to hemorrhoids rather than a more serious condition.

However, it is essential to remain vigilant, especially if you have a family history of colorectal cancer. While your immediate family may not have a significant history of cancer, having a relative with colorectal cancer can increase your risk. The general recommendation is to begin screening for colorectal cancer at age 45, or earlier if there is a family history of the disease.

If you continue to experience gastrointestinal symptoms, such as changes in bowel habits, persistent abdominal discomfort, or any new symptoms, it would be prudent to consult with a healthcare provider. They may recommend further evaluation, such as a colonoscopy, to rule out any serious conditions, including cancer.
In summary, while blood in the stool can be a symptom of stomach or colon cancer, it is not always present, and many other benign conditions can cause similar symptoms. It is essential to monitor your symptoms and seek medical advice if you have concerns, especially given your family history. Regular screenings and open communication with your healthcare provider can help ensure early detection and appropriate management of any potential issues.

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