Colon Cancer: Causes, Symptoms, and Risk Factors

Have you ever wondered why your bowel habits have changed, or why there’s unexplained fatigue hanging over you? While it’s often nothing serious, sometimes these signs could point to something more—like colon cancer. It’s a condition that can feel overwhelming to think about, but knowing the facts can help ease your worries. 

This article is here to give you simple, clear information about colon cancer—its causes, signs, risks, and treatments—so you can take charge of your health with greater peace of mind.

What is Colon Cancer?

Colon cancer begins in the large intestine (colon), which is part of your digestive system. This type of cancer typically starts as small, noncancerous (benign) clumps of cells called polyps that form on the inside of the colon. Over time, some of these polyps can become cancerous. 

Recognising colon cancer symptoms early and seeking prompt medical advice can greatly improve outcomes. It’s important to understand the basics so you can make confident decisions about your health or support someone who’s going through this.

Colon Vs Colorectal Cancer

Colon cancer and colorectal cancer are often used interchangeably, but they aren't exactly the same. Let’s clarify the difference.

Understanding the distinction can help when reviewing colon cancer treatment plans and discussing symptoms or options with your healthcare provider.

How Colon Cancer Develops?

Colon cancer usually develops over several years. It often starts with tiny growths on the inner lining of your colon called polyps. While most polyps are harmless, some can turn into cancer over time. 

These abnormal cells may multiply uncontrollably, forming a tumour. If left untreated, the cancer can grow through the colon wall and spread to nearby lymph nodes and other organs. This progression tends to be slow, which is why regular screening can be lifesaving. Detecting and removing polyps early can prevent cancer from developing in the first place. 

Knowing how the disease begins helps you take proactive steps towards prevention and early detection, especially if you're at higher risk.

Types of Colon Cancer

Colon cancer comes in different forms. Each type behaves a little differently and may affect your colon cancer treatment options. Here's what you need to know:

• Adenocarcinoma (most common)

This is the type you'll hear about most often—over 90% of colon cancers fall into this category. It starts in the mucus-producing glands of the colon lining. Within this group, subtypes like mucinous adenocarcinoma or signet ring cell adenocarcinoma may behave more aggressively.

• Carcinoid tumours

These cancers begin in hormone-producing cells in your colon. They're rare and often grow more slowly than adenocarcinomas. Symptoms might be subtle or absent until later stages.

• Gastrointestinal stromal tumours (GISTs)

These start in the specialised cells in the wall of the colon, known as interstitial cells of Cajal. GISTs can be benign or malignant and require different treatments from more common colon cancers.

• Lymphoma

Although more common in lymph nodes, lymphomas can originate in the colon. These are cancers of the immune system cells and typically need chemotherapy as the main form of treatment.

• Sarcomas

These originate in the connective tissues of the colon, like muscle or blood vessels. Sarcomas of the colon are very rare and may require both surgery and chemotherapy.

Common Symptoms Of Colon Cancer

Colon cancer symptoms can vary depending on the stage and location of the tumour. You might not notice any signs early on, which is why regular screenings are so important. However, certain symptoms can act as warning signs. Being aware of them can help you take action sooner.

Early-Stage Colon Cancer Symptoms

In the early stages, symptoms can be mild or vague. It’s easy to mistake them for less serious issues. Still, don’t ignore persistent changes in your digestive health.

• Changes in bowel habits

You might notice you're having diarrhoea or constipation more frequently than usual. Even subtle shifts in your regular routine can be worth checking out.

• Narrow or ribbon-like stools

A consistent change in the shape of your stool could indicate a blockage or tumour affecting the passage of waste.

• Unexplained fatigue

If you're feeling unusually tired without a clear cause, it could be related to blood loss or your body fighting an early tumour.

• Mild abdominal discomfort

Cramping or bloating that doesn’t go away might be your body's way of signalling that something isn’t quite right.

Advanced-Stage Colon Cancer Symptoms

As colon cancer progresses, symptoms tend to become more noticeable and severe.

• Rectal bleeding or blood in your stool

This can appear as bright red blood or darker, tarry stools. It’s a key symptom and should never be ignored.

• Unexplained weight loss

Losing weight without trying may be due to the cancer affecting your metabolism or appetite.

• Persistent abdominal pain

Pain that becomes more intense or constant may indicate a growing tumour or spread to nearby organs.

• Feeling of incomplete bowel emptying

You may feel like you still need to go, even after a bowel movement. This can be a sign of a tumour blocking the rectum.

Knowing these colon cancer symptoms gives you the power to act early and seek medical advice when necessary.

Colon Cancer Causes

It’s natural to want to know why cancer happens. While there’s often no single cause, several factors can increase your risk of developing colon cancer. Here are some common causes:

• Gene mutations

Most cases begin with changes in the DNA of colon cells, causing them to multiply out of control.

• Family history

If a close relative has had colon or colorectal cancer, your risk is higher.

• Inflammatory bowel diseases (IBD)

Conditions like Crohn’s disease or ulcerative colitis can increase your risk due to prolonged inflammation.

• Ageing

Your risk rises significantly after age 50, though younger people can be affected too.

Lifestyle Choices That Are Risk Factors for Colon Cancer

Certain habits can affect your chances of developing colon cancer. Adjusting these lifestyle factors may help lower your risk:

• Low-fibre, high-fat diet

Diets rich in red or processed meats and low in fruits and vegetables can increase risk over time.

• Lack of physical activity

A sedentary lifestyle may contribute to weight gain and slower digestion, both of which are linked to higher cancer risk.

• Obesity

Being significantly overweight is strongly associated with increased colon cancer risk, especially in men.

• Smoking

Long-term tobacco use doesn’t only affect your lungs—it can damage the colon lining too.

• Heavy alcohol consumption

Regular heavy drinking may irritate the colon lining and lead to increased cancer risk.

Medical Conditions That Increase Colon Cancer Risk

Some health conditions make you more prone to developing colon cancer. Being aware helps you monitor your health more closely.

• Type 2 diabetes

People with insulin resistance often have an increased risk of colon cancer.

• Lynch syndrome

A hereditary condition that dramatically increases your risk due to gene mutations affecting cell repair.

• Familial adenomatous polyposis (FAP)

This rare genetic condition causes numerous polyps to form in the colon, often at a young age.

• Previous cancer history

If you've had colorectal, ovarian, or breast cancer, your risk is slightly elevated.

How is Colon Cancer Detected?

Detecting colon cancer early can be lifesaving. Because many colon cancer symptoms don’t appear until later stages, regular screening plays a crucial role—especially if you're over 50 or have risk factors. Doctors use several tools to detect potential problems, and the process is more manageable than you might think.

Screening Methods

Screening is about finding signs of cancer before symptoms appear.

• Faecal occult blood test (FOBT)
  This checks for hidden blood in your stool. It's simple and can be done at home.
• Faecal immunochemical test (FIT)
  A more specific version of FOBT that doesn’t require dietary restrictions.
• Stool DNA test
  This test looks for genetic markers and blood in your stool that may suggest cancer.
• Flexible sigmoidoscopy
  A thin tube with a light is used to view the lower part of your colon.
• Colonoscopy
  The gold standard for colon cancer detection. It examines your entire colon and allows removal of polyps during the procedure.

Diagnostic Tests

If screening finds something suspicious, further tests help confirm a diagnosis.

• Biopsy
  A small tissue sample is taken from the colon and analysed under a microscope.
• CT colonography (virtual colonoscopy)
  A specialised CT scan that produces detailed images of your colon.
• Blood tests
  These may include tests for anaemia or tumour markers like CEA (carcinoembryonic antigen).

Staging Colon Cancer

Once diagnosed, doctors determine how far the cancer has spread.

• Stage I: Cancer is limited to the inner layers of the colon.
• Stage II–III: The tumour has grown deeper or spread to nearby lymph nodes.
• Stage IV: Cancer has spread to distant organs, like the liver or lungs.

Treatment Options for Colon Cancer

If you or a loved one has been diagnosed, it's natural to feel scared. But take heart—colon cancer treatment has come a long way, and many people go on to live full, healthy lives after treatment. Your treatment plan will depend on the type, stage, and location of the cancer, as well as your overall health.

Surgical Treatments

Surgery is often the first step in treating colon cancer, especially in early stages.

• Polypectomy and local excision
  If the cancer is caught early and is still small, it may be removed during a colonoscopy without needing further surgery.
• Partial colectomy (hemicolectomy)
  In more advanced cases, a portion of your colon is removed along with nearby lymph nodes. The healthy parts of your colon are then reconnected.
• Colostomy
  If reconnecting your colon isn’t possible, a colostomy may be done to create an opening (stoma) for waste to leave your body.

Chemotherapy & Radiation

These treatments may be used alone or alongside surgery.

• Chemotherapy
  This involves using drugs to kill cancer cells or stop them from growing. It may be given before surgery to shrink the tumour, or after to reduce recurrence risk.
• Radiation therapy
  High-energy beams target cancer cells. This is more commonly used for rectal cancer but may also be used for colon cancer in specific cases.

Immunotherapy & Targeted Therapy

Newer therapies offer hope for people with advanced or recurrent colon cancer.

• Immunotherapy
  This boosts your immune system’s ability to fight cancer. It's especially effective for cancers with certain genetic markers (like MSI-high).
• Targeted therapy
  These drugs focus on specific genes or proteins that help cancer grow. They can block blood supply to the tumour or interfere with cell growth signals.

Palliative Care

Even when a cure isn't possible, you still deserve comfort and support.

• Symptom management
  Focuses on relieving pain, fatigue, and other symptoms that may arise from cancer or treatment.
• Emotional support
  Helps you and your loved ones cope mentally and emotionally. This care is holistic and aims to improve your overall quality of life.

No matter the stage, colon cancer treatment should be tailored to fit your individual needs and preferences. You're not in this alone.

When to See a Doctor?

It’s easy to brush off minor digestive issues. But some signs should never be ignored.

• If you notice persistent changes in your bowel habits—such as diarrhoea, constipation, or stool shape changes—don’t wait to mention it.
• Any bleeding from the rectum or blood in the stool should be investigated promptly.
• Unexplained fatigue, weight loss, or abdominal discomfort are worth discussing too.

Early action can lead to early detection—and that can make all the difference. Don’t hesitate to reach out to a doctor if something feels off.

Conclusion

Colon cancer may feel overwhelming, but you’re not powerless. With early detection, awareness of colon cancer symptoms, and the right support, outcomes can significantly improve. Taking small steps—like regular screenings and timely consultations—can lead to peace of mind and better health. 

If you’re looking for a reliable diagnostic partner, Metropolis Healthcare offers advanced, accurate testing backed by expert pathologists and convenient home collection services. Their commitment to quality and early diagnosis makes them a trusted choice for anyone taking proactive steps toward better health.