Colorectal cancer often called bowel cancer or colon and rectal cancer develops in the large intestine (colon) or rectum. It can begin as a growth called a polyp, and some polyps can eventually become cancerous. Importantly, colorectal cancer may cause no symptoms in its early stages, which is why screening is so important.
When symptoms do appear, they can sometimes be mistaken for haemorrhoids, constipation, food intolerance, gastritis or other digestive problems. Having one of these symptoms does not mean you have cancer, but persistent or unexplained changes deserve medical evaluation.
1. Blood in Your Stool
One of the most important warning signs is blood in the stool.
The blood may appear:
- Bright red
- Dark red
- Very dark or black
- Mixed with the stool
- On the surface of the stool
- On toilet paper
Bleeding from the bowel can have many causes, including haemorrhoids, but it can also be a sign of colorectal cancer.
Don't simply assume it is haemorrhoids.
If blood in your stool is unexplained, recurrent or accompanied by changes in bowel habits, see a healthcare professional.
2. A Persistent Change in Bowel Habits
Pay attention when your usual bowel pattern changes and doesn't return to normal.
For example, you may suddenly experience:
- Constipation
- Diarrhoea
- Softer stools
- More frequent bowel movements
- Less frequent bowel movements
- Alternating constipation and diarrhoea
The important point is not whether you normally have constipation or diarrhoea.
It is whether there is a new and persistent change from your usual pattern.
3. Feeling Like You Still Need to Pass Stool
Another possible warning sign is the persistent feeling that you need to have a bowel movement—even after you have just used the toilet.
You may feel:
“I still need to go.”
This sensation is sometimes called tenesmus.
It can occur when there is irritation or narrowing affecting the rectum or bowel.
It does not automatically indicate cancer, but persistent symptoms should be evaluated.
4. Your Stool Becomes Narrower or Changes Shape
A noticeable change in stool shape can sometimes occur when the passage through the bowel becomes narrowed.
You may notice stools that are:
- Narrower than usual
- Different in shape
- Consistently thinner than your normal stool
However, stool shape can vary for many harmless reasons.
A persistent change—especially when combined with blood, abdominal pain or altered bowel habits—should be discussed with a doctor.
5. Persistent Abdominal Pain or Cramping
Colorectal cancer can sometimes cause:
- Abdominal pain
- Cramping
- Gas pains
- Discomfort
- A feeling of fullness
- Bloating
The pain may come and go or persist.
But abdominal pain is extremely common and can result from many other conditions.
What matters is persistent, unexplained or progressively worsening discomfort, particularly when it occurs together with other bowel symptoms.
6. Persistent Bloating
Occasional bloating after a large meal is common.
However, persistent or unusual bloating deserves attention, especially if it is accompanied by:
- Abdominal pain
- Changes in bowel habits
- Unexplained weight loss
- Blood in the stool
- Feeling that your bowel does not empty completely
Bloating has many possible causes, so it should not be treated as proof of cancer.
7. Unexplained Weight Loss
Losing weight without deliberately changing your diet or exercise routine can be a warning sign.
For example:
“I haven't been trying to lose weight, but my clothes are becoming noticeably looser.”
Unexplained weight loss can occur with colorectal cancer, but it can also result from many other medical conditions.
If the weight loss is significant or continues, medical evaluation is important.
8. Persistent Tiredness
Unusual or persistent fatigue can sometimes be associated with colorectal cancer.
One reason is that slow bleeding from the bowel may contribute to iron-deficiency anaemia, which can cause tiredness and weakness.
You might notice:
- Low energy
- Weakness
- Difficulty concentrating
- Getting tired more easily
- Reduced ability to perform normal activities
Fatigue can have countless causes, so it is not specific to cancer. However, persistent fatigue combined with bowel symptoms deserves attention.
9. Shortness of Breath
Some people with bowel cancer may develop anaemia because of chronic blood loss.
Anaemia can result in:
- Fatigue
- Weakness
- Shortness of breath
- Reduced exercise tolerance
The NHS specifically lists tiredness and shortness of breath among symptoms that can occur because of anaemia associated with bowel cancer.
If you experience unexplained shortness of breath, particularly with severe fatigue or other symptoms, seek medical advice.
10. A Lump or Unusual Swelling in the Abdomen
A lump in the abdomen can occasionally be associated with bowel cancer.
You may notice:
- A new lump
- Persistent abdominal swelling
- An unusual feeling of fullness
Most abdominal lumps are not automatically cancerous and can have many different causes.
Nevertheless, a new or persistent abdominal lump should be assessed by a healthcare professional.
11. Nausea or Vomiting
Nausea and vomiting can occur with colorectal cancer, particularly when there are problems with the movement of contents through the bowel.
However, nausea and vomiting are much more commonly caused by infections, food poisoning, medication effects and other gastrointestinal conditions.
Persistent vomiting—especially when combined with severe abdominal pain, swelling or inability to pass stool or gas—requires urgent medical assessment.
12. A Feeling That Your Bowel Isn't Emptying Properly
You may have a bowel movement but still feel that something remains.
This can manifest as:
“I went to the toilet, but I still feel like I need to go.”
Persistent incomplete evacuation is one of the symptoms associated with colorectal cancer.
Again, this symptom has many possible causes, including benign bowel conditions.
13. Mucus in the Stool
Mucus can sometimes appear in stool for a variety of reasons.
Persistent or unusual mucus, especially when accompanied by:
- Blood
- Diarrhoea
- Abdominal pain
- Changes in bowel habits
should be discussed with a healthcare professional.
Some clinical bowel-cancer resources include increased mucus among possible symptoms.
14. Changes That Keep Coming Back
One isolated episode of constipation after changing your diet isn't necessarily concerning.
The bigger concern is a pattern.
For example:
Normal bowel habits → persistent constipation → diarrhoea → constipation again
or:
Normal stool → consistently altered stool shape → abdominal discomfort
A persistent change from your normal pattern deserves attention.
15. Sometimes There Are NO Symptoms
This is perhaps the most important point.
Colorectal cancer can exist without obvious symptoms, especially early in the disease.
The CDC notes that people can have colorectal cancer and not know it because symptoms may not be present, particularly in the early stages.
This is why screening matters.
You should not wait until you see blood in your stool or experience severe abdominal pain before thinking about colorectal-cancer screening.
Why Early Detection Matters
Colorectal cancer can begin as a precancerous polyp.
Screening can detect abnormal growths, and some polyps can be removed before they develop into cancer.
This is one of the reasons colorectal cancer screening can be so valuable.
Screening is not only about finding cancer.
It can also help prevent cancer by identifying and removing precancerous growths.
Who May Have a Higher Risk?
Risk can increase with factors such as:
- Increasing age
- A close family history of colorectal cancer
- Previous colorectal polyps
- Inflammatory bowel disease, including Crohn's disease or ulcerative colitis
- Certain inherited genetic conditions
- Smoking
- Being overweight
Having a risk factor does not mean you will develop cancer.
Likewise, having no known risk factor does not guarantee that you won't.
Family History Matters
If a close family member has had colorectal cancer or certain types of colorectal polyps, tell your healthcare professional.
Some people with increased inherited or family-related risk may need screening earlier or more frequently than people at average risk.
What Tests Can Detect Colorectal Cancer?
Depending on your age, symptoms and risk profile, healthcare professionals may recommend different tests.
These can include:
Stool-based tests
A stool sample can be examined for hidden blood.
One example is the faecal immunochemical test (FIT).
Colonoscopy
A flexible camera is used to examine the colon and rectum and can allow doctors to remove certain polyps or take biopsies.
Other examinations
Depending on the circumstances, doctors may use other imaging or endoscopic tests.
The appropriate test depends on your symptoms and individual risk.
Don't Be Embarrassed to Talk About Bowel Symptoms
Many people delay seeing a doctor because they feel embarrassed discussing:
- Stool
- Rectal bleeding
- Bowel movements
- Constipation
- Diarrhoea
But healthcare professionals discuss these symptoms regularly.
The NHS specifically encourages people not to be embarrassed about discussing bowel-cancer symptoms.
A few minutes of an uncomfortable conversation could potentially lead to an important diagnosis.
When Should You See a Doctor?
You should arrange a medical assessment if you notice persistent or unexplained:
🩸 Blood in your stool
🚽 Changes in bowel habits
💩 Persistent diarrhoea or constipation
🎈 Persistent bloating
🤕 Abdominal pain or cramping
⚖️ Unexplained weight loss
😴 Persistent tiredness
🫁 Unexplained shortness of breath
🚨 A feeling that your bowel isn't emptying properly
If symptoms continue for around three weeks or more, NHS guidance recommends speaking with a doctor.
Don't wait for every symptom to appear.
When Is It an Emergency?
Some bowel symptoms require urgent attention.
Seek urgent medical help if you experience:
- Heavy or continuous rectal bleeding
- A large amount of blood or blood clots
- Black or very dark stools with concerning symptoms
- Bloody diarrhoea
- Severe abdominal pain with vomiting or significant abdominal swelling
- Inability to pass stool or gas with severe abdominal symptoms
Heavy rectal bleeding or symptoms suggesting bowel obstruction require urgent medical assessment.
Important: Blood in the Stool Doesn't Always Mean Cancer
This is an important balance.
Blood in the stool can also be caused by:
- Haemorrhoids
- Anal fissures
- Inflammatory bowel disease
- Polyps
- Infections
- Other gastrointestinal problems
The NHS notes that blood in stool is often caused by conditions other than bowel cancer, including haemorrhoids.
Therefore:
Don't panic—but don't ignore it either.
Get it checked.
A Simple Warning-Sign Checklist
🚨 WATCH FOR THESE CHANGES
🩸 BLOOD IN STOOL
Red, dark red or black stool.
🚽 BOWEL HABIT CHANGES
New constipation, diarrhoea or unusual frequency.
💩 DIFFERENT STOOL
Persistent change in shape or appearance.
🤕 ABDOMINAL PAIN
Unexplained or persistent cramps or discomfort.
🎈 BLOATING
Frequent or persistent abdominal swelling.
⚖️ UNEXPLAINED WEIGHT LOSS
Losing weight without trying.
😴 EXTREME FATIGUE
Persistent tiredness, potentially related to anaemia.
🫁 SHORTNESS OF BREATH
Particularly when accompanied by fatigue.
🚨 INCOMPLETE BOWEL EMPTYING
Constant feeling that you still need to go.
🤢 NAUSEA OR VOMITING
Especially when persistent or associated with obstruction symptoms.
The Most Important Lesson
The biggest mistake is thinking:
“It is probably just haemorrhoids.”
Or:
“It's probably just constipation.”
Or:
“I'll wait and see.”
Sometimes it really is something minor.
But persistent bowel changes deserve a proper evaluation.
And remember:
Colorectal cancer can occur without obvious symptoms.
That's why screening and timely medical assessment are so important.
Final Takeaway
The warning signs of colorectal cancer can be subtle.
The most important ones to remember are:
🩸 Blood in the stool
🚽 Persistent changes in bowel habits
💩 A persistent change in stool shape
🤕 Abdominal pain or cramps
🎈 Persistent bloating
⚖️ Unexplained weight loss
😴 Persistent fatigue
🫁 Shortness of breath from possible anaemia
🚨 Feeling that the bowel doesn't empty completely
🤢 Persistent nausea or vomiting
None of these symptoms automatically means you have cancer. Many are caused by much more common conditions.
But if a symptom is new, persistent, unexplained or getting worse, don't ignore it.
LISTEN TO YOUR BODY. CHECK PERSISTENT CHANGES. DON'T WAIT FOR SYMPTOMS TO BECOME SEVERE.
And perhaps most importantly:
You don't need to have symptoms to benefit from appropriate colorectal-cancer screening.
Screening can sometimes detect colorectal cancer early—and can also identify precancerous polyps before they become cancer.
Medical disclaimer: This article is intended for general health education and does not diagnose colorectal cancer. Bowel symptoms have many possible causes. If you have concerning or persistent symptoms, consult a qualified healthcare professional for appropriate examination and testing.
Tiada ulasan:
Catat Ulasan