Colon cancer is one of the most prevalent cancers in the world, and early detection of cancer can have a positive impact on treatment success. Abdominal pain and unexplained weight loss are common early signs of colon cancer, but one of the first indications is changes in your stool.
Stool changes may also occur with many types of digestive disease, such as hemorrhoids, irritable bowel syndrome (IBS), infections and inflammatory bowel disease. This does not necessarily mean that abnormal stools are a sure sign of colon cancer. If symptoms continue for 2-3 weeks or are accompanied by other worrisome symptoms, however, it is important to have a medical evaluation.
This guide will provide you with information about the appearance of unhealthy stools that may be linked to colon cancer, symptoms to watch for, common causes and when to see your health care provider.
Does Colon Cancer Affect The Color Of Stools?
Yes. Bowel movements may be altered in form, colour, consistency and frequency due to colon cancer. This is typically the case when a tumour either partially obstructs the colon or causes bleeding in the digestive tract.
Stool changes are not always present, particularly in the early stages of colon cancer. Similarly, a great deal of stools are due to non-cancerous factors. The concern is if there are changes that are ongoing or inexplicable, especially if they are accompanied by other symptoms.
What Do Colon Cancer Stools Smell Like?
Although there isn’t one specific “colon cancer stool,” healthcare providers look for certain patterns that may require further evaluation.
1. Stool With Blood
One of the best-known symptoms of colon cancer is blood in the stool.
The blood may look like:
- Blood in stool or on toilet paper that is bright red
- Black or bloody poop
- Dark, black, tar-like stool if bleeding is from the upper digestive tract
Any blood loss, no matter how small, is a cause for concern and should be addressed, particularly if it occurs on a regular basis.
2. Pencil-Thin Or Narrow Stools
A tumor may cause a narrowing of the inside of the colon and cause stools to become very thin.
Characteristics include:
- Narrow, ribbon-like stools
- Pencil-shaped bowel movements
- A persistent change in the diameter of the stools.
The occasional narrow stool is generally not a cause for concern, but if stools are changing in their shape, then it should be investigated.
3. Bloody Or Black Stools
Soiled stools may be caused by ingestion of blood due to bleeding in the gastrointestinal tract.
But black stools may also occur due to:
- Iron supplements
- Certain medications
- Foods such as black licorice
If black stools happen for no apparent reason, then medical evaluation is warranted.
4. Soft Or Watery Poop
The cancer in the colon can affect the way the bowel works, causing some people to have chronic diarrhea.
Signs include:
- Frequent loose stools
- Persistent diarrhea
- A rare and pressing need to urinate or defecate.
If the diarrhea lasts for several weeks, it’s time to see a doctor.
5. Constipation
Bowel obstruction may occur in part due to colon cancer and cause stools to be hard to pass.
Symptoms include:
- Fewer bowel movements
- Hard stools
- Straining
- Feeling that the bowel doesn’t empty completely
Prolonged constipation (particularly associated with abdominal pain or blood loss) should be evaluated.
6. Mucus In Stool
If there is too much mucus, this can be a sign of an underlying condition that needs to be evaluated a small amount can be normal. Some stool changes may be serious enough to seek medical intervention.
The following combinations are more alarming as they may have other causes other than dietary changes
- A combination of blood and stool.
- Persistent pencil-thin stools
- Black or tarry stools for no apparent reason
- Persistent constipation or diarrhea for 2-3 weeks or longer.
- An alternating intestinal problem, characterized by constipation and diarrhea.
- Weight loss not due to known causes, along with changes in bowel habits
- Unreflected abdominal pain and abnormal stools
These symptoms are not a positive diagnosis of colon cancer, but should lead to medical evaluation.
Other signs of colon cancer are:
Many people with colon cancer may experience other symptoms besides changes in bowel habits.
Abdominal Pain
Pain may be:
- Cramping
- Persistent discomfort
- Bloating
- Abdominal pressure
If you have an urge to defecate but are unable to do so.An urge to defecate but the bowel does not empty. Others may still feel the urge to have a bowel movement after going to the bathroom.
This Feeling Can Be Constant As The Tumor Grows
Fatigue
Feeding may be slow and may result in iron-deficiency anemia in the case of colon cancer.
Symptoms include:
- Extreme tiredness
- Weakness
- Dizziness
- Shortness of breath
Unexplained Weight Loss
Weight loss that doesn’t involve diet or exercise changes should always be discussed with a health care provider, particularly if there are bowel changes.
Loss Of Appetite
As the disease advances, some loss of appetite may occur which can lead to unwanted weight loss.
What Other Causes Of Stool Change Are There Besides Colon Cancer?
The majority of stool changes are due to reasons other than cancer.
Hemorrhoids
Bright red blood can be a symptom of hemorrhoids.
Anal Fissures
Small tears around the anus may result in pain and bleeding during bowel movements.
Irritable Bowel Syndrome (IBS)
IBS commonly causes:
- Constipation
- Diarrhea
- Bloating
- Abdominal pain
IBS is not a cancer or intestinal bleeding disorder.
Infections
Diarrhoea and stool mucous may be seen for a short while due to food poisoning and gastrointestinal infections.
Inflammatory Bowel Disease (IBD)
Both Crohn’s disease and ulcerative colitis can lead to:
- Bloody stools
- Abdominal pain
- Chronic diarrhea
- Weight loss
- They need continuous medical treatment
Who Is More At Risk For Colon Cancer?
The more of the following factors that are present, the greater the risk will be:
- Over 45 years old
- History of colon cancer in the family.
- History of colon polyps (self-diagnosed)
- Inflammatory bowel disease
- Obesity
- Smoking
- Heavy alcohol consumption
- Physical inactivity
- Consume excessive processed and red meat.
- Type 2 diabetes
For some people, having a risk factor means that they are more likely to get colon cancer, but it does not mean that they will get colon cancer.
When To See A Doctor?
If you have any of the following symptoms, you should see your doctor:
- Blood in your stool
- Black or tar-like stools
- Long-term bowel changes that continue for 2-3 weeks or longer
- Ongoing abdominal pain
- Unexplained weight loss
- Severe fatigue
- Persistent pencil-thin stools
- Signs and symptoms of bowel obstruction (high pain, vomiting, and not passing stool or gas) that need immediate medical attention
Diagnosis at an early stage can assist in determining the cause of cancer or something else related to the digestive system.
Diagnosis Of Colon Cancer
A healthcare provider might order one or more tests if colon cancer is suspected.
Colonoscopy
A colonoscopy is the best test because it lets the doctor see the colon directly and remove or biopsy any suspicious polyps or tissue while the colonoscopy is in progress.
Stool Tests
There are some stool screening tests that can identify DNA changes and/or blood that may be abnormal and associated with colorectal cancer. These tests can be helpful in screening certain people, but cannot be used in place of a colonoscopy if symptoms occur.
Blood Tests
Blood tests can help detect anemia due to chronic bleeding and may provide other helpful information, but cannot diagnose colon cancer on their own.
Imaging Tests
Imaging tests such as CT scans may be performed to help find out if cancer has spread after it has been diagnosed, or to check some symptoms.
Is Colon Cancer preventable?
While not all cases can be avoided, there are some healthy practices that can lower your risk.
These include:
- Following recommended colorectal cancer screening guidelines
- A high-fiber, high-fruits and vegetables, high whole grains diet
- Eating less processed and red meats.
- Exercising regularly
- Maintaining a healthy weight
- Avoiding tobacco
- Limiting alcohol consumption
- Taking care of chronic health issues like diabetes
Regular screenings can help find precancerous polyps, before they turn into cancer.
Final Thoughts
Alterations in bowel movements can be a helpful indicator of digestive health, but not just colon cancer. Medical attention is warranted for all cases of blood in the stool, persistent pencil-thin stool, black stool, persistent diarrhea or constipation, or unexplained changes in bowel habits that last more than 2-3 weeks or if they are accompanied by abdominal pain, fatigue, or unexplained weight loss.
The positive news is that when colon cancer is diagnosed early, it’s very treatable. It can help make a difference to remember to watch for ongoing symptoms and follow recommended colorectal cancer screenings. Don’t rely on stool color as the sole indicator for diagnosing a problem, talk to a qualified healthcare provider if you notice any changes in bowel habits that continue over time.
