Colon

Nick, Holly, Faleesa , Bret , Eyob , Jake , Dustin Grade 1- Well differentiated Grade 2- Moderatedly-well differentiated Grade 3- Poorly differentiated
 * **Epidemiolgy:** || Last year, colon cancer with the addition of rectal cancer, lead to the 2nd most common cause of cancer deaths. 1 It also had enough incidences to become the third most common cancer in both men and women. ||
 * **Etiology:** || While an increase in age is a common risk factor, there has yet to be a correlation with gender. 1 Dietary factors such as a high fat content or low fiber meals can also cause an increase in risk for colon cancer. Finally, obesity, smoking, and alcohol have shown to increase the chances of many cancers with colon being just one of them. ||
 * **Signs & Symptoms:** || * Abdominal pain (most common) 2
 * Change in bowel habits
 * Nausea
 * Vomiting
 * Anemia
 * Abdominal mass ||
 * **Diagnostic Procedures:** || * Detailed H&P 2
 * Attention to any extrarectal mass by palpation (may suggest peritoneal spread)
 * Pelvic exam (females only)
 * Barium enema or colonoscopy
 * Proctosigmoidoscopy (if colonoscopy not done)
 * Chest x-ray
 * CT or MRI of abdomen and pelvis
 * CBC and blood chemistry profile
 * Carcioembryonic antigen
 * Molecular biologic markers ||
 * **Histology:** || The most common histologic malignancy of the colon is adenocarcinoma. 3 It accounts for 90%-95% of all tumors. Mucinous adenocarcinoma, signet-ring cell carcinoma, and squamous cell carcinoma account for the remaining tumors. ||
 * **Lymph node drainage:** || The initial chain of lymph nodes draining the colon is the epicolic nodes. 4 These nodes drain into the regional chains of lymph nodes which are the ileocolic, right colic, middle colic, and left colic lymphatic chains. The regional lymph nodes drain into the superior and inferior mesenteric lymph nodes. ||
 * **Metastatic spread:** || The 3 routes of metastatic spread from the colon are direct extension, lymphatics, and hematogenous spread. 3 Direct extension usually travels radially and can involve the bowel wall rather than longitudinally. The lymphatics that are typically involved include the superior mesenterics, ileocolic, right and left colic nodes, inferior mesenteric, midcolic, superior rectal, sigmoidal, and sigmoidal mesenteric nodes. The most common areas of distant metastasis are the liver, lungs, and peritoneal cavity. ||
 * **Grading:** || Colon Cancer uses the 3 tier grading system including:

*Most colon cancer are moderately well histology. 2 ||
 * **Staging:** || Stage 0: A cells are found in the mucosa (innermost layer) of the colon wall. These abnormal cells may become cancer and spread. This is also called carcinoma in situ.

Stage I: Cancer has spread from the mucosa of the colon wall to the muscle. Stage II: In stage IIA, cancer has spread through the muscle layer of the colon wall to the serosa. In stage IIB, cancer has spread through the serosa but has not spread to nearby organs. In stage IIC, cancer has spread through the serosa to nearby organs.

Stage III: In stage III, colon cancer may have spread through the mucosa of the colon wall to the submucosa and muscle layer, and has spread to one to three nearby lymph nodes.

Stage IV: Cancer may have spread through the colon wall and may have spread to nearby organs or lymph nodes. Cancer has spread to one organ that is not near the colon, such as the liver, lung, or ovary, or to a distant lymph node. 5 || Kidneys: 1800-2300 centigray (cGy) Liver: 3000-3500 cGy Small bowel: 4000-4500 cGy Spinal cord: 4500-4700 cGy Stomach: 5000 cGy ||
 * **Radiation side effects:** || Side effects of radiation therapy for colon or rectal cancer include skin soreness, nausea, diarrhea, trouble controlling your bowels, rectal or bladder irritation, and tiredness. Sexual problems may also occur. Side effects often go away or lessen over time after treatment is finished, but problems such as rectal and bladder irritation may remain. 6 ||
 * **Prognosis:** || Aneuploidy and high proliferative index (measured by adding percentage of cells in S phase to those in G2 and M phase) are associated with worse survival in colorectal cancer. 2 Patients are also at a risk for increased local recurrence if the tumor has penetrated bowel wall and if there is lymph node involvement. Randomized studies have shown no increase in 5 year survival rate by having chemo 62% or chemo with radiation 58%. 2 ||
 * **Treatments:** || Chemotherapy is the primary method of treatment for colon cancer. Post operative irradiation can be considered in patients with positive or close to positive surgical margins. 2 It can also be considered for patients with T4 lesions adherent to the pelvic structure. The difficult part for radiation therapy for colon cancer is trying to delineate the region of interest. Adequate imaging is very important and the surgeon may also need to place surgical clips during surgery. 2 ||
 * **TD 5/5:** || The normal tissue tolerance dose at 5% normal tissue complication probability (NTCP) within 5 years after radiotherapy 3 :
 * **References** || # Chao K, Perez C, Brady L. // Radiation Oncology Management Decisions // . 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002.
 * 1) Chao K, Perez C, Brady L. // Radiation Oncology Management Decisions // . 3rd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2011.
 * 2) Washington CM, Leaver D. // Principles and Practice of Radiation Therapy // . 3rd ed. St. Louis, MO: Mosby Elsevier; 2010.
 * 3) Lymph node drainage of the colon and anus. Springer images Web site. [] . 1996. Accessed June 14, 2013.
 * 4) Stages of Colon Cancer. National Cancer Institute Web site. http://www.cancer.gov/cancertopics/pdq/treatment/colon/Patient/page2. Accessed June 11, 2013
 * 5) Colorectal cancer overview. American Cancer Society Web site. [] . Accessed June 11, 2013. ||

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