Colon Cancer: Symptoms, Stages, Causes, Diagnosis and Treatment

Ignorance is bliss. What you don’t know cannot hurt you is the meaning of this famous proverb. This may be true to life in general but unfortunately this is completely opposite in case of Cancer. If you are diagnosed at an early stage of cancer, the chances of your survival are very high. Today, we’ll learn everything about colorectal cancer, the third most common type of cancer behind Lung cancer and Breast cancer.
Colorectal Cancer is the development of cancer at colon, rectum or parts of large intestine. It often starts as the development of small, non cancerous clumps of cells called adenomatous polyps. Overtime, some of these polyps become large and develop as colon cancer.

Symptoms for Colorectal Cancer

Signs and symptoms of colorectal cancer can vary, but commonly include:

• Change in bowel habits, such as diarrhea, constipation, or a change in stool consistency
• Blood in the stool, which may appear as bright red or give stools a black appearance
• Persistent abdominal pain, cramps, or bloating
• Rectal bleeding
• Mucus discharge from the rectum
• Pain during defecation or while passing stools
• Sensation of a lump in the anus
• Loss of appetite
• Unexplained weight loss
• Fatigue or weakness

Many of these symptoms can also be caused by conditions other than colorectal cancer. If any of these symptoms persist for more than four weeks, it is important to consult a doctor for proper diagnosis and evaluation.

Causes for Colorectal Cancer

Most colorectal cancer are caused due to lifestyle factors and increasing age. Only a small number of cases are related to genetic disorders. Most common causes are:

• Food high in fat and low in fiber diet
• Older age (50+)
• Obesity
• Smoking
• Red and processed meat
• Lack of physical activity

Some of the Inherited gene mutations also increase the risk of colon cancer although these genes are linked to only a small percentage of colon cancer cases. Most common gene mutations that have a high chance of developing colon cancer are:
Hereditary nonpolyposis colorectal cancer (HNPCC)​ also called Lynch syndrome, increases the risk of colon cancer and other cancers. People with HNPCC tend to develop colon cancer before age 50.
Familial adenomatous polyposis (FAP) ​FAP is a rare disorder that causes you to develop thousands of polyps in the lining of your colon and rectum. People with untreated FAP have a greatly increased risk of developing colon cancer before age 40.

Diagnosis of Colorectal Cancer

Diagnosing colorectal cancer in its early stages can be challenging, as polyps are often small and may not cause noticeable symptoms. For this reason, doctors recommend routine screening tests to detect and remove polyps before they progress into cancer.

Screening Tools Used for Diagnosing Colorectal Cancer

• Digital Rectal Examination (DRE): A simple, manual examination useful for detecting masses or rectal bleeding. Recommended annually after the age of 40.
• Faecal Occult Blood Test (FOBT): Detects hidden (occult) blood in stool, which can be an early sign of cancer. Recommended once every year after age 40.
• Flexible Sigmoidoscopy: Enables direct visual examination of the rectum and lower colon. Recommended once every 5 years after age 50.
• Colonoscopy: Examines the rectum and entire colon. A liquid diet is advised 1–2 days before the test. Small procedures like biopsy and polyp removal can be performed during this test. Sedation is usually given. Recommended once every 10 years after age 50.
• Double-contrast Barium Enema / X-ray:
  Helps visualize the lining of the intestine. Recommended every 5–10 years after age 50.

Other Investigations Helpful to Confirm Diagnosis

• Blood Tests: To detect anaemia, which may result from chronic blood loss in colorectal cancer.
• MRI and/or CT Scans: Used to assess cancer spread (metastasis) and determine the stage of cancer. These imaging tests are crucial in treatment planning, as decisions depend largely on cancer staging and whether metastasis has occurred.

Treatment options such as surgery, chemotherapy, and radiotherapy depend on multiple factors, including the patient’s overall health, the location, size, and stage of cancer, and whether the cancer has recurred.

Stages of Colorectal Cancer:

Once you’ve been diagnosed with colon cancer, doctors suggest some tests to determine the stage of the colon. Knowing the stage of the cancer helps in determining what treatment is appropriate for you and the treatment plan to be followed.
The stages of colon cancer are:

• Stage I: ​Your cancer has grown through the superficial lining (mucosa) of the colon or rectum but hasn’t spread beyond the colon wall or rectum.
• Stage II:​Your cancer has grown into or through the wall of the colon or rectum but hasn’t spread to nearby lymph nodes.
• Stage III:​Your cancer has invaded nearby lymph nodes but isn’t affecting other parts of your body yet.
• Stage IV:​Your cancer has spread to distant sites, such as other organs — for instance, to your liver or lung.

Treatment for Colorectal Cancer

Treatment for colorectal cancer largely depends on the stage of the disease, the location of the tumor (colon or rectum), and the overall health of the patient. The three primary treatment options include surgery, chemotherapy, and radiation therapy.

Surgical Treatment

Surgery is the first-line treatment for most colorectal cancers that are deemed resectable. Types of surgery vary by stage and tumor location:

• Early-stage Colorectal Cancer:
  • Endoscopic Mucosal Resection (EMR) and
  • Minimally Invasive Surgery (MIS) may be used to remove small, localized tumors.
• Invasive or Advanced Local Cancer:
  • Partial Colectomy (removal of the affected colon segment) and
  • Lymph Node Removal are often necessary when the cancer has penetrated deeper layers.
• Rectal Cancer (All Stages):
  • Neoadjuvant Therapy (chemotherapy and/or radiation before surgery) may be used to shrink the tumor.
  • Surgery follows based on tumor response.
  • Adjuvant Therapy (post-surgery chemotherapy or radiation) may also be advised based on final staging.

Chemotherapy

Chemotherapy uses cancer-killing drugs to destroy cancer cells. It may be used:

• Before surgery (neoadjuvant) – to shrink large tumors
• After surgery (adjuvant) – to eliminate any remaining cancer cells and reduce the risk of recurrence
• In advanced or metastatic cancer – to slow progression and relieve symptoms

Radiation Therapy

Radiation therapy uses high-energy beams to destroy cancer cells or stop them from multiplying. It is:

• Commonly used in rectal cancer
• Typically administered before surgery to shrink the tumor
• Sometimes used after surgery to reduce recurrence risk
• May be combined with chemotherapy (chemoradiation)

Expert Treatment at Apollo Hospitals

The Institute of Colorectal Surgery at Apollo Hospitals is equipped with state-of-the-art technology, including Robotic and Laparoscopic surgery systems, and performs over 1,200 colorectal surgeries annually.

Apollo is also one of the first dedicated centres for Anorectal Diseases in India, offering expert care in:

• Proctology
• Pelvic Floor Disorders
• Minimally Invasive & Robotic Colorectal Surgeries

For personalized treatment plans, patients are encouraged to consult Apollo's colorectal surgery specialists.

Lifestyle Measures & Prevention

• Get timely screenings: especially after age 45
• Eat a fibre-rich diet: include fruits, vegetables, whole grains, and plenty of fluids
• Exercise regularly and maintain a healthy weight
• Avoid smoking and limit alcohol consumption

Conclusion

Numerous lifestyle measures, such as regular screenings, moderate, regular exercises, nutritional diet, and maintaining healthy body weight, can reduce the risk of getting colorectal cancer.