Colorectal cancer Guide, Meaning , Facts, Information and Description
Colorectal cancer includes cancerous growths in the colon, rectum, anus, and appendix. It is the third most common form of cancer and the second leading cause of death among cancers in the United States.
Many colorectal cancers are thought to arise from polypss in the colon. These mushroom-like growths are usually benign, but some may develop into cancer over time.
Causes
Colorectal cancer is a disease resulting from mutations in epithelial cells lining the gastrointestinal tract. Most of the known abnormalities involve the DNA which regulates cell growth. Though many of these effects are well known, there are likely environmental, hereditary, and viral causes for specific cell defects. Because the changes at the cell level may take years to develop into cancer, it is generally impossible to track the cause of specific cases of cancer. Thus efforts at prevention mostly focus on avoiding or identifying risk factors and early detection.
Cancers on the right side (ascending colon and caecum) tend to be exophytic, that is the tumour grows outwards from one location in the bowel wall. This very rarely causes obstruction of feces, and present with symptoms such as anaemia.
Left-sided tumours tend to be circumferential, and can obstruct the bowel like a napkin ring.
The systems for staging colorectal cancers largely depend on the extent of local invasion, the degree of lymph node involvement and whether there is distant metastases or not.
The most common currently used system for staging is the TNM system, though some doctors still use the older Duke's system. The TNM system assigns a number :
The stage of a cancer is usually quoted as a number I,II,III,IV derived from the TNM value grouped by prognosis; a higher number indicates a more advanced cancer and a likely worse outcome.
Surgery remains the primary treatment while chemotherapy and/or radiotherapy may be recommended depending on the individual patient's staging and other medical factors.
Laparoscopic assist resection of the colon for tumour can reduce the size of painful incision and minimize the risk of infection.
As with any surgical procedure, colorectal surgery can in rare cases result in complications. These may include infection, abscess, fistula or bowel obstruction.
Risk Factors
The lifetime risk of developing colon cancer in the United States is about 7%.
Certain factors increase a person's risk of developing the disease. These include:
Symptoms
Symptoms of colorectal cancer include
It is also possible that there will be no symptoms at all. This is one reason why screening for the disease is recommended. Diagnostics, Screening and Monitoring
Colorectal cancer can take many years to develop and early detection of colorectal cancer greatly improves the chances of a cure. Therefore, screening for the disease is recommended in individuals who are at increased risk. There are several different tests available for this purpose.Pathology
The pathology of the tumor is usually reported from the analysis of tissue taken from a biopsy or surgery. A pathology report will usually contain a description of cell type and grade. The most common colon cancer cell type is adenocarcinoma which accounts for 95% of cases. Other types include lymphoma and squamous cell carcinoma.Staging
Colon cancer staging is an estimate of the condition of a particular cancer for patient diagnostic and research purposes.
for example for a patient with no disease would be T0N0M0.AJCC stage groupings
Treatment
The treatment depends on the staging of the cancer. When colorectal cancer is caught at early stages (with little spread) it can be curable. However when it is detected at later stages (when distant metastases are present) it is less likely to be curable.Surgery
Surgical treatment is by far the most likely to result in a cure of colon cancer if the tumor is localized. Very early cancer that develops within a polyp can often be cured by removing the polyp at the time of colonoscopy. More advanced cancers typically require surgical removal of the section of colon containing the tumor leaving sufficient margins to reduce likelihood of re-growth. If possible, the remaining parts of colon are anastomosed together to create a functioning colon. In cases when anastomosis is not possible, a stoma (artificial orifice) is created.
Surgery is generally not offered if significant metastasis are present.Radiation therapy
Radiation therapy is used to kill tumor tissue before surgery or when surgery is not indicated. It is also used to sterilize the margins after surgery is performed. Sometimes chemotherapy agents are used to increase the effectiveness of radiation by sensitizing tumor cells if present.Chemotherapy
Chemotherapy is used to reduce the likelihood of metastasis developing, shrink tumor size, or slow tumor growth. Chemotherapy is often applied after surgery (adjuvant), before surgery (neo-adjuvant), or as the primary therapy if surgery is not indicated (palliative). The treatments listed here have been shown in clinical trials to improve survival and/or reduce mortality and have been approved for use by the US Food and Drug Administration.Experimental Therapies
The treatments listed here are currently undergoing clinical trials and are not approved for general use by the US Food and Drug Administration.Alternative Therapies
The agents listed here are not proven in clinical trials but may be considered to have anti-colon cancer properties in in-vitro studies, the popular press, folk medicine or other sources. Support Therapies
Cancer diagnosis very often results in an enormous change in the patients sociological wellbeing. Various support resources are available from, hospitals and other agencies which provide counseling, social service support, cancer support groups, and other services. These services help to mitigate some of the difficulties of integrating a patients medical complications into other parts of their life.
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