Colon cancer often whispers before it screams. That’s the scary part — its earliest signs can be brushed off as “just a stomach issue” or “something I ate.” But what if those little changes were your body’s way of waving a red flag?
In this article, we’ll break down 10 early signs of colon cancer that deserve your attention. We’re not here to scare you — just to help you stay informed. After all, early detection saves lives.
1. Persistent Changes in Bowel Habits
Have your toilet habits changed lately?
Maybe you’re going more often… or not enough. Perhaps your stool looks different — looser, harder, or oddly shaped. These aren’t just minor annoyances. If these changes stick around for more than a few weeks, they might point to something more serious.
Colon cancer can affect how your intestines process waste. So, persistent diarrhoea, constipation, or a mix of both might be worth a conversation with your doctor.
2. Blood in the Stool or Rectal Bleeding
Here’s a question people often avoid: Have you seen blood in the toilet?
Bright red blood or darker, tar-like stools can both be warning signs. Some dismiss it as haemorrhoids — and yes, it often is. But that assumption can be risky if left unverified.
Blood in the stool could be from a tumour bleeding inside the colon. And the scariest part? Sometimes, it’s microscopic — you won’t even see it without a test.
Bottom line? Blood in the toilet should never be ignored.
3. Unexplained Weight Loss
You’re dropping kilos… but not trying to. Should you celebrate or be concerned?
Unintended weight loss — especially if it’s more than 5% of your body weight in a few months — can be a red flag. Cancer cells use up a lot of energy, and tumours can also mess with how your body absorbs nutrients.
If the weight is falling off without any diet changes or workouts, your body could be telling you something.
4. Abdominal Pain or Cramping
It’s easy to blame stomach pain on gas, stress, or a bad lunch.
But if you keep feeling cramps, bloating, or pressure in your belly — especially in a specific spot — it might not be just indigestion. Tumours growing in the colon can cause blockages or irritation, leading to that persistent, dull (or sometimes sharp) ache.
Ask yourself: “Has this pain been sticking around longer than it should?” If yes, get it checked.
5. Feeling of Incomplete Evacuation
Ever finish a bowel movement and still feel like you need to go again?
That feeling of “not quite done” is called tenesmus. It’s frustrating — and easy to dismiss. But in some cases, it’s caused by a tumour obstructing the colon or rectum, making it hard to fully empty your bowels.
If this sensation keeps coming back, it’s more than a nuisance — it’s a clue.
6. Fatigue or Weakness
Tired all the time? Even after a good night’s sleep?
It’s one thing to be tired after a long week. But if your energy is constantly running on empty, that’s a sign your body might be fighting something. Colon cancer can cause chronic internal bleeding, which leads to anaemia — and that leads to fatigue.
If you’re needing naps more often, struggling to focus, or just feeling “off” energy-wise, listen to your body.
7. Iron Deficiency Anaemia
This one’s sneaky — you may not even know you’re anaemic until a blood test shows it.
Low iron levels, especially in men and postmenopausal women, can sometimes be the first clue that something’s wrong in the colon. Why? Because tumours may slowly bleed over time, causing iron loss without obvious symptoms.
Signs of iron deficiency include:
- Pale skin
- Shortness of breath
- Dizziness
- Heart palpitations
If you’ve been told you’re anaemic and the cause isn’t clear, a colon check-up might be in order.
8. Narrow or Pencil-Thin Stools
Sounds odd, doesn’t it? But yes, the shape of your stool can tell a story.
If your poop has become noticeably thinner or pencil-shaped, it could indicate a narrowing in the colon caused by a tumour. While occasional changes aren’t usually serious, consistent stool shape changes shouldn’t be overlooked.
It’s awkward to talk about. But health comes before embarrassment.
9. Gas, Bloating, or Fullness
We all get gassy sometimes. But if you’re feeling bloated after small meals, or just always full… it might be more than indigestion.
A tumour pressing against parts of the colon can disrupt normal digestion and gas flow, causing persistent bloating and discomfort. If your belly feels tight, swollen, or crampy for no reason, that’s a reason to pause.
Don’t wait for pain to escalate — trust the subtle cues.
10. Nausea or Vomiting
This is usually the last straw for most people.
When colon cancer causes a significant blockage, waste can’t move through the intestines like it should. This can lead to nausea, vomiting, and abdominal distension. At this stage, things have likely progressed further — so catching symptoms earlier is key.
If you’re throwing up and also have constipation, bloating, or pain, seek help immediately.
When Should You Worry?
It’s normal to experience one of these symptoms from time to time. But if you’re noticing a pattern or more than one symptom that sticks around for weeks, don’t wait.
Colon cancer is one of the most treatable cancers when caught early. That’s the good news.
But many people delay seeing a doctor — either out of fear, embarrassment, or just being too busy.
Your life is worth the check-up.
How to Protect Yourself
- Know your family history — genetics play a big role
- Get screened — especially after age 45 (or earlier if you’re high risk)
- Listen to your body — you know it better than anyone
And most importantly: Don’t ignore small signs. They might be your biggest allies.
References
- American Cancer Society. “Signs and Symptoms of Colorectal Cancer.” Cancer.org, 2023. https://www.cancer.org/cancer/colon-rectal-cancer/detection-diagnosis-staging/signs-and-symptoms.html
- National Cancer Institute. “Colorectal Cancer Screening.” Cancer.gov, 2022. https://www.cancer.gov/types/colorectal/patient/colorectal-screening-pdq
- Mayo Clinic. “Colon Cancer – Symptoms and Causes.” MayoClinic.org, 2023. https://www.mayoclinic.org/diseases-conditions/colon-cancer/symptoms-causes/syc-20353669