Colon cancer is a type of cancer where the proliferation of cancer cells usually happens in the colon (large intestine), the final part of the digestive tract or the tube that arises from the back of the mouth and ends at the anus. It is the part of the gastrointestinal system which chiefly functions by drawing out water and salt from solid wastes, thereby allowing the waste to pass through the rectum and exits the body through the anus in the form of faeces.

Colon cancer illustration

Colon Cancer usually originate from small, non-cancerous or benign lumps (tissues or cells banding together to form polyps) that happen on the insides of the colon. These polyps may be more or less in number and the ones that show initial carcinogenic characteristics require immediate removal from time to time as if these polyps are not treated on time, they may gradually become malignant in nature and turn into colon cancer. The colon and the rectum cancer are together known as the colorectal cancer.

Also Read: Rectal Cancer: Causes, Symptoms And Treatment


Although the exact cause of colon cancer is yet to be discovered, several studies and researches shed light that it chiefly happens due to certain changes or mutations in the DNA of the cells of the colon. This faulty DNA triggers the healthy cells to grow abnormally in size, shape and number without dying and bundle up together to form tumorous growths. These tumours may gradually spread and destroy healthy cells and tissue along the surrounding areas.

Also Read: Anal Cancer: Causes, Symptoms And Treatment

Risk Factors

Certain causative factors that influence the formation of colon cancer includes:

Age: Although colon cancer can occur at any age, it usually affects older people above 50.

Ethnicity: People belonging to the African-American race is more prone to developing colon cancer.

Polyps: Presence of large number of polyps in the colon or rectum may increase the chances of colon cancer.

Previous Colon Cancer: Having a history or colorectal cancer in the past increases recurrence of colon cancer.

Family History: Having a family history with close relatives or parents diagnosed colon cancer increases the risk in the children as well.

Inflamed Gastric Conditions: People suffering from gastrointestinal disorders like inflammatory bowel disease, Crohn’s disease or Ulcerative colitis have an increased risk of colon cancer.

Genetic Factors: Some genetic mutations passed through the generations within the family like Lynch syndrome (also known as hereditary nonpolyposis colorectal cancer (HNPCC)) or familial adenomatous polyposis (FAP) increases the risk of colon cancer in the individual.

Dietary Choices: People opting for a diet consisting of high fat, low fibre and minimum fluids is more prone to developing colon cancer over time.

Sedentary Lifestyle: A lifestyle with no regular activities, poor food timings increase the risk of colon cancer.

Unhealthy Habits: Habits such as smoking or consumption of too much alcohol increases the risk of colon cancer.

Health Conditions: People suffering from insulin resistance or diabetes or those who are obese are more prone to developing colon cancer later in their lives.

Exposure To Radiation: Radiation therapy used for treating other cancerous conditions that were mainly aimed at the abdomen increases the risk of colon cancer.


In most cases, there are usually no distinct symptoms in the early stages, the ones that do appear in some people includes:

  • Diarrhoea
  • Constipation
  • Change in bowel habits
  • Blood in bowel
  • Dark-coloured stool
  • Extreme narrow bowels
  • Prolonged rectal bleeding
  • Abdominal cramps and pain
  • Painful bowel movements
  • Excessive gas
  • General debility
  • Sudden weight loss
  • Feeling that the bowel isn’t empty completely
  • Irritable bowel syndrome
  • Ulcerative colitis
  • Crohn’s disease
  • Diverticulitis


On noticing any of the above-mentioned signs and symptoms, it is strictly advocated to consult a doctor at the earliest to get diagnosed and start treatment as early as possible. The doctor usually does a thorough physical examination by slightly pressing the lower abdomen, acknowledges the patient’s past medical history, genetic and family history and conducts a few diagnostics including:

  • Colonoscopy
  • Faecal occult blood test
  • Endoscopy
  • Digital rectal examination
  • Imaging techniques like Ultrasounds, CT-scan, PET-scan, Barium X-ray etc.

Staging Of Colon Cancer:

Stage I: Cancer cells usually develop on the inner lining of the colon (i.e. mucosal layer), sometimes within a polyp.

Stage II: The cancer cells have spread through the wall of the colon into nearby structures.

Stage III: In this stage, the cancer cells have spread into nearby lymph nodes.

Stage IV: The cancerous cells have metastasized into distant organs or lymph nodes far away from the colon.


Treatment options usually depend upon the severity of the condition, and staging of the cancer cells. This includes:

Early-stage colon cancer treatment involves:

  • Polypectomy (removal of polyps via colonoscopy)
  • Endoscopic mucosal resection
  • Laparoscopic surgery

Advanced-stage colon cancer treatment involves:

  • Partial colectomy
  • Ostomy (creating a new pathway for waste removal from the body)
  • Removal of affected lymph node

Other treatment options include:

  • Surgery
  • Chemotherapy
  • Radiation therapy
  • Targeted therapy
  • Immunotherapy
  • Supportive care