Colon Cancer: Symptoms and the Role of Colonoscopy in Detection

May 1, 2024

Colon cancer, one of the leading causes of cancer-related deaths, often begins as small, benign clumps of cells called polyps that form on the inside of the colon. Over time, some of these polyps can become colon cancers. Early detection through screening such as colonoscopy is crucial because symptoms may not appear until the cancer has progressed and become more difficult to treat.

Symptoms of Colon Cancer

Colon cancer doesn’t always cause symptoms in its early stages, which is why regular screening is so important. When symptoms do appear, they may vary depending on the cancer’s size and location in the large intestine. Common symptoms include:

  • Changes in Bowel Habits Including diarrhea, constipation, or a change in the consistency of your stool that lasts longer than four weeks.
  • Rectal Bleeding or Blood in Stool: One of the most noticeable signs, presenting as bright red or very dark blood.
  • Persistent Abdominal Discomfort: Such as cramps, gas, or pain.
  • Feeling that Your Bowel Doesn’t Empty Completely: An urge that persists even after a bowel movement.
  • Weakness or Fatigue: This can occur with or without visible bleeding.
  • Unexplained Weight Loss: Often rapid and significant.

The Role of Colonoscopy in Detecting Colon Cancer

A colonoscopy is considered the gold standard for colon cancer screening. It allows for a visual examination of the entire colon and rectum using a long, flexible tube equipped with a video camera at the end. Here’s how it plays a crucial role in the detection and prevention of colon cancer:

Detection and Removal of Polyps

During a colonoscopy, doctors can find and remove polyps before they have the chance to turn into cancer. This removal is a critical step in preventing colon cancer.

Diagnosis of Colon Cancer

If signs of cancer are found during a colonoscopy, samples of tissue (biopsy) can be taken for analysis. Colonoscopy offers the most accurate diagnosis and localization of tumors in the colon.

Colonoscopy Procedure

Here’s what you can expect during a colonoscopy:

  • Preparation: Preparation involves following a special diet the day before the exam and taking a laxative solution to clean out the colon.
  • Procedure: The procedure itself usually lasts about 30 to 60 minutes. Sedation is typically used to keep patients comfortable and relaxed.
  • Recovery: Recovery from the sedative can take about an hour, and patients will need someone to drive them home. Patients may feel a bit bloated or have mild cramps and gas pains.

Importance of Regular Screening and Early Detection

Regular screening and early detection of colon cancer are paramount in reducing the mortality rate associated with the disease. The American Cancer Society recommends that individuals at average risk of colon cancer begin regular screenings at age 45. These screenings can identify abnormalities and cancers in their earliest stages when treatment is most effective. For those with a family history of colon cancer or other risk factors, starting screenings earlier or undergoing screenings more frequently may be advised. Advocating for regular check-ups and awareness of the signs and symptoms of colon cancer can significantly impact outcomes, emphasizing the critical nature of proactive health measures in combating this disease.

Prevention and Risk Factors for Colon Cancer

Understanding and mitigating the risk factors for colon cancer can significantly lower one’s chances of developing the disease. Lifestyle choices play a crucial role, with diet, physical activity, and smoking being key factors. A diet high in red and processed meats can increase risk, while a diet rich in fruits, vegetables, and whole grains has been shown to decrease risk. Regular physical activity is also associated with a lower risk of developing colon cancer. Additionally, avoiding smoking and limiting alcohol consumption can further reduce the risk. Genetic factors and a family history of colon cancer or polyps can increase an individual’s risk, making it important for those with a family history to discuss their risk and screening options with a healthcare provider.

When to Get Screened

Screening guidelines recommend that individuals at average risk of colon cancer start regular screening at age 45. Those with risk factors, such as a family history of colon cancer or a personal history of inflammatory bowel disease, may need to start earlier and be screened more frequently.


Understanding the symptoms of colon cancer and the preventive role of colonoscopy can lead to early detection and a significantly better prognosis. Regular screening is a powerful tool in the fight against colon cancer, as it can detect the disease at its most treatable stages or prevent it altogether by removing precancerous polyps. If you are experiencing any of the symptoms mentioned or are due for a screening, consult with your healthcare provider to discuss the best course of action.