Colon Cancer

Colon cancer or what is also known as large bowel cancer and colorectal cancer involves cancerous growths in the colon, rectum and appendix.

It placed third as the most common form of cancer and the second leading cancer-related death in the Western world. Globally, colon cancer is also the third leading most common cancer in males and the fourth leading cause of cancer in females. It was also found that the frequency of colon cancer varies around the world and it is more common in the Western world and is rather rare in Asia and Africa.

The symptoms present in colon cancer are numerous and nonspecific. The first symptoms that usually appear are quite vague, like weight loss and fatigue (tiredness). Colon cancer can even be present for several years before symptoms actually develop.

The symptoms and signs of colon cancer can be divided into three groups which are local, constitutional and metastatic.

Local symptoms

• Constitute a change in bowel habits
• Frequency change (constipation and/or diarrhoea),
• Feeling of incomplete defecation (tenesmus) and reduction in diameter of stool, both characteristic of rectal cancer,
• Stools' change in appearance
• Rectal bleeding or bloody stool
• Mucus in stool
• Black, tar-like stool (melena), more likely related to upper gastrointestinal organs like the stomach or duodenal disease.
• Obstruction in bowel causing bowel pain, bloating and vomiting of stool-like material.
• There's a tumour in the abdomen, felt by patients or their doctors.
• Symptoms related to invasion by the cancer of the bladder which is causing hematuria (blood in the urine) or pneumaturia (air in the urine), or invasion of the vagina which is causing smelly discharge in the vagina. Although these are already late events, indicative of a large tumour.

Constitutional (systemic) symptoms

• Probably the most common symptom is unexplained weight loss which is caused by lack of appetite.
• Dizziness, fatigue and palpitations which lead to anaemia. Clinically, there will be unusual paleness and blood tests will confirm the low hemoglobin level.

Metastatic symptoms

• Liver metastases, causing :
• Jaundice.
• Abdominal pain, more often the upper part of epigastrium or right side of the abdomen.
• Enlargement of the liver, usually felt by a doctor.
• Clotting of blood in the veins and arteries, a paraneoplastic syndrome related to hypercoagulability of the blood (the blood is "thickened")