Colon Cancer Symptoms, Pictures, Causes, Treatment

What is colon cancer?

Colon cancer is the cancer affecting the colon, the major portion of the large bowel. Usually the rectum is also affected and therefore colon cancer is now more commonly referred to collectively as colorectal cancer. Common symptoms are long term passage of loose stool, constipation (change of bowel habit) and bloody stool. Like any other cancer, the cause of colon cancer is not very clear, but increasing age, lifestyle habits along with genetic abnormalities are the common factors held responsible. Colon cancers if diagnosed at an early stage, when still confined to the walls of the colon, are curable with surgery. More advanced cases, where the ccancer that has spread to other regions of the body, are managed with chemotherapy (drugs), radiation and surgery.

Colon Cancer Symptoms

The symptoms of colon cancer can arise from the effects of a malignancy in the colon, or once the cancer spreads to other organs in the body.

Colon Symptoms

  • Change in the bowel habits :
    - persistent passage of loose stool
    - constipation
    - change in the character of the stool
  • Frank blood in the stool
  • Lethargy and fatigue
  • Sudden weight loss without any identifiable cause.
  • Loss of appetite

Spread of Cancer Symptoms

  • Jaundice due to cancer spread to the liver.
  • Fluid accumulation in the abdomen due to spread to the peritoneum – the protecting covering of all the abdominal organs.
  • Repeated lung infections and bloody sputum due to spread to the lungs.

Pictures of Colon Cancer

Picture from Wikimedia Commons

Picture of cancer in the colon after colectomy from Wikimedia Commons

Picture of cancer in the colon (endoscopic image) from Wikimedia Commons

Colon Cancer Causes

The normal cells of the body become cancerous whenever there is imbalance between new cell generation (cell division) and old cell death (apoptosis-programmed cell death). Therefore in cancers there are “immortal cells” with the capacity of producing new “immortal cells” that can spread (metastasis) to other organs via the blood stream or lymphatic system. Genetic mutation, which is an unexplained, sudden and irreversible change in the genes, is the main cause for development of cancer. In colon cancer, the APC gene is the most commonly mutated gene associated with colon cancer.

Risk Factors of Colon Cancer

Although the exact cause of colon cancer is not known there are factors which may lead to colon cancer namely :

  • Precancerous lesions in the colon. There are certain colonic polyps (growth) which when removed surgically reduce the risk of colon cancer development in the future.
  • Genetics. Only 5% to 10% of colon cancers occur in genetically susceptible people. A family history of colon cancer especially in first degree relatives increases the chance of colon cancer. There are some common varieties of colon cancer that are hereditary namely familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC).

Other general risk factors include :

  • Advancing age increases the risk of colon cancer. More that 90% of cases of colon cancer occur in persons above 50 years of age
  • Race. African Americans are at a greater risk.
  • Family history.
  • Previous history of colon cancer.
  • Diets that are low in fiber and high in fat.
  • Sedentary lifestyle and obesity.
  • Associated medical conditions like inflammatory bowel disease (Crohn’s disease and ulcerative colitis) and diabetes mellitus.
  • Smoking and alcohol may have some role to play in the development of colon cancer.

Colon Cancer Treatment

Colon cancer is treatable and curable in the early stages. However, totally removing the cancer does not mean that it cannot recur. Therefore patients who have previously had colon cancer that was successfully treated need to be regularly screened for recurrence. Similarly, people with a strong family history of colon cancer and precancerous lesions also need to monitored frequently. Depending upon the stage of the cancer, the treatment strategy may vary.

  • In the early stage colon cancer is treated with laparoscopic surgery. The tumor along with a small area of the surrounding healthy tissue is resected. The prognosis for a complete cure is much better.
  • For late stage colon cancer, open abdominal surgery is performed where larger portions of the colon is removed (colectomy), along with lymph nodes an any spread to other tissue. The prognosis is poor with such radical surgery.
  • In advanced cases chemotherapy (cancer drugs) and radiation may be to chemically or mechanically destroy the cancer cells, and sometimes even healthy tissue.

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