Pathophysiology of Colon Cancer

According to the United States Cancer Statistics (2010), colorectal cancer is one of the most commonly diagnosed cancers in America as of 2006.  There are an estimated 70,270 men and 68,857 women who were diagnosed with colorectal cancer (cited in US Cancer Statistics Group 2010, web-based report).

The progression of colorectal cancer has been known to begin with may start as a benign polyp but may become malignant, invade, and destroy normal tissues, and extend into surrounding structures (cited in Brunner and Suddharths textbook of medical-surgical nursing 2008, p. 1070).  There are several disorders and preexisting conditions known to be linked to colorectal cancer, including familial adenomatous polyposis, such as Gardners syndrome and Peutz-Jeghers syndrome, ulcerative colitis, Crohns disease, Turcots syndrome, hereditary nonpolyposis colorectal carcinoma, and other pelvic cancers treated with abdominal radiation (ibid, p. 22).

A malignant polyp contains cancerous cells and is invasive (cited in Madara  Denino 2008, p. 423).  The authors further expounded that the time it takes for a benign polyp to develop malignancy is 10 to 15 years with genetic mutations occurring in a predictable manner.  The epithelial lining of the intestine usually is the site of adenocarcinoma where 95 of the cancer of the colon and rectum begins to develop.   The effects of progression of colorectal cancer start locally in the area close to the anus.  The patient with colorectal cancer may experience a change on bowel habits and a feeling of incomplete defecation.  Thus, it is important to assess patients for a possible sign of colorectal cancer when there is lower gastrointestinal bleeding and increased presence of mucus.  When the cancer progress, the tumor can grow into a size large enough to obstruct the bowel thus leading to constipation, abdominal distention, and vomiting.  Based on my experience, my great aunt died of colorectal cancer lost a significant amount of weight, chronic anemia, jaundice, decreased appetite and abdominal pain.

 Kemeny  Dizon stated, sixty percent of patients diagnosed with colorectal cancer go on to develop hepatic metastases (Bleiberg  Kemeny 2002, p. 359).  Based on this finding, the abdominal pain experienced by my late aunt is due to the stretching of the capsule covering the liver.  The only site of colorectal cancer is the liver by as many as 30 of patients.  The authors elaborated that in general, the liver is a frequent site of metastatic involvement by a variety of tumors, including breast, colon, lung, stomach, and pancreas.  The portal circulation of the liver provides a rich, blood supply and changes how cancer calls originating from the colon.  When these cancer cells grow beyond 3 mm angiogenesis enables them to form their own system for the supply of blood, which they draw from the arterial circulation (ibid 2002, p. 360).  Furthermore, cases of colorectal cancer have a physiologic rationale for hepatic metastasis due to the drainage of the gastrointestinal tract by the portal system of the liver (ibid 2002, p. 359).


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