Carcinoma of Large Intestine - Case Study Example

Colon cancer is carcinoma of large intestine. Colon cancer does not exhibit clear symptoms until it has reached advanced stage. It starts with benign clumps of cells which slowly turn into cancerous adenomatous polyps. Severity of clinical symptoms decides mortality of colon cancer patients. The treatment options like surgery, chemotherapy, radiation therapy etc depend on the stage of the cancer. Early stage diagnosis of colon cancer and its treatment, may actually cure the cancer. The distant metastases which are found in later stages are difficult to treat. The death rate for colon cancer is dropped in recent decade due to increased awareness and screening by colonoscopy. Follow-up is indicated to check recurrence of colon cancer after surgery. Novel approach is essential to study colon cancer and their symptoms for effective drug therapy. A general clinical database should be established for colon cancer patients including their personal as well as family history and clinical signs to track the treatment. Colon cancer is cancerous growth in the colon. Colon starts from large intestine and end of the colon is rectum. So colon cancer is also called a ‘Colorectal cancer’. In cancer, normal cells grow abnormally and give rise to transformed cells which eventually spreads in the body. These evade on healthy cells, tissues and organs by depriving them of essential nutrients and space. First benign tumors are developed in the glands, which are lining inner wall of the colon. These benign tumors slowly develop into carcinomas and are referred as ‘adenocarcinomas’. American Cancer Society has reported that colorectal related deaths are third highest in the United States. Causes of Colon Cancer The factors which augment chances for developing colon cancer are as follows (Park et al., 2005; Levin and Dozois, 1991; Hamilton, 1985): Adenomatous polyps in the colon in individuals Hereditary nonpolyposis colorectal cancer Family history of adenomatous polyposis Ulcerative colitis or Crohn’s disease Individual history of breast, uterine or ovarian cancer Dietary high fat, low fiber intake Smoking and/or heavy alcohol consumption Clinical Manifestations Colon cancer does not exhibit clear symptoms until it has reached advanced stage. Consult the doctor when indications like bowel related Symptoms (Diarrhea or constipation, blood in the stool, incomplete defecation sensation, bowel obstruction, shrinking in the stool size), abdominal pain, rectal pain and bleeding from the rectum, unjustified reduction in the weight, and anemia with nausea, vomiting, dizziness are observed. Diagnosis The diagnostic techniques are as follows: Digital rectal exam: This test helps in locating only large tumors which are present in the distant part of the colon by inserting a gloved finger into the rectum. Fecal Occult Blood Test: This test detects blood in the stool. But positive test does not necessary indicates colon cancer. Endoscopy: i) Colonoscopy: Colonoscope is inserted into the rectum to examine polyps, tumors and other abnormalities throughout the entire colon. ii) Sigmoidoscopy: Sigmoidoscope is inserted into the rectum to look for polyps, tumors and other abnormalities in the rectum or descended part of the colon. Fecal Occult Blood Test and Sigmoidoscopy in combination can be done. Imaging tests: i) Double contrast barium enema/ Air contrast barium enema: First bowl is fully evacuated overnight by laxative. Barium sulphate is administered in the rectum. X-ray shows a thin layer of barium over the inner lining of the colon and detects polyps. Small flat tumors are not detected. ii) Computed tomography scan: Radiologist interprets polyps in the scan. iii) Positive Emission Tomography (PET): Whole body PET is done for detection of recurrent colon cancer. Accuracy of imaging studies should be increased to study cancer abnormalities. Stool DNA test: Stable DNA of cancer cells can be isolated from stool and amplified by PCR. Sensitivity limit is 71-91% (Greenwald, 2006). Carcinoembryonic antigen (CEA): Increase in concentration of this tumor marker in patient’s serum indicates cancer. Staging Staging is done to indicate the extent of involvement of layers of the colon and other parts of the body in colon cancer. Different types of classification of staging are as follows: Dukes system : Dukes classify stages as (Dukes, 1932): A - Tumor confined to the intestinal wall B- Tumor invading through the intestinal wall C - With lymph node(s) involvement D- With distant metastasis TNM system: The TNM system identifies stages as number (Wittiekind and Sobin, 2002): T - The degree of invasion of the intestinal wall (T0, Tis, T1, T2, T3, T4) N - The degree of lymphatic node involvement (N0, N1, N2) M - The degree of metastasis (M0, M1) A higher number indicates, a cancer is in advanced stage. AJCC stage groupings: These are quoted as a number I, II, III, IV and are derived from the TNM value. AJCC stage groupings are done to decide advanced stage carcinoma. Treatment Early stage diagnosis of colon cancer and its treatment, may actually cure the cancer. About 65% of patients survive for at least 5 years and recurrence may not occur. The distant metastases which are found in later stages are difficult to cure. In such cases surviving rate drops to 8%. Surgery: Surgery is opted as the primary treatment to remove affected parts of the colon that can not be cured. Cancerous tumors are removed at the time of colonoscopy (Winawer et al., 1993). Colostomy is performed when removal of cancerous rectum becomes necessary. New opening to evacuate fecal matter is constructed near belly. Non curative multiple metastases are also surgically removed to prevent further bad effects. Chemotherapy: Chemotherapy reduces mortality rate of patients by killing cells and thus decrease size and growth of the tumor and prevents development of metastasis. Combination of 5-flurouracil, leucovorin, oxaliplatin (FLO) is given in stage III and IV cancer. For metastasis treatment, FLO in combination with bevacizumbab is given. These treatments are accepted by US Food and Drug Administration. Radiation therapy: This is indicated only in specific cases like stage III rectal cancer in combination with chemotherapy. This is therapy is restricted in specific cases because radiation also spreads in unwanted area causing harm and body retains radiation products. Immunotherapy: Bacillus Calmette-Guerin mixed with autologous cancer cells can be helpful to treat colon cancer (Mosolits, Nilsson and Mellstedt, 2005). Vaccine: Development of ‘Trovax’ vaccine positively treats cancer by boosting immune system of the patient. Support therapies: Mental agony of cancerous patients is but natural. Support from family members, friends, social workers, counselors and cancer support groups help patients to come out of depression. A general clinical database should be established for colon cancer patients including their history and clinical signs to track the drug efficacy. Follow-up American Society of Clinical Oncology provides guidelines for the follow-up (Desch et al., 2005; Figueredo et al., 2002). A medical history and physical examination is done for every 3 to 6 months for 2 years, then every 6 months for 5 years. Colonoscopy is done within 3 months after removal of obstructing mass by surgery. In other cases, colonoscopy is suggested after 1 year and repeated after every 3 years. CEA level measurement is indicated to check recurrence of colon cancer after surgery. Prevention To prevent or lower risk of colon cancer following precautions are taken (Potter and McMichael, 1986; Su and Arab, 2004; Cummings and Bingham, 1998; Folssman and Rothwell, 2007): Screening by colonoscopy for people older than 50 years Intake of high fiber and low fat diet Quit smoking and heavy alcohol consumption Take an aspirin after consulting doctor Prevention of colon cancer is always better than cure. Reference 1. Cummings, J. H., and Bingham, S. A. (1998). Diet and the prevention of cancer. BMJ, 317, 1636-1640. 2. Desch, C. E., Benson, A. B. 3rd, Somerfield, M. R, et al. (2005). American Society of Clinical Oncology. Colorectal cancer surveillance: update of an American Society of Clinical Oncology practice guideline. Jounal of Clinical Oncology , 23 (33), 8512-8519.  3. Dukes, C. E. (1932). The classification of cancer of the rectum. Journal of Pathological Bacteriology, 35, 323. 4. Figueredo, A., Rumble, R. B., Maroun, J., et al. (2003). Gastrointestinal Cancer Disease Site Group of Cancer Care Ontarios Program in Evidence-based Care. Follow-up of patients with curatively resected colorectal cancer: a practice guideline. BMC Cancer, 3, 26.  5. Flossmann, E., and Rothwell, P. M. (2007). Effect of aspirin on long-term risk of colorectal cancer: consistent evidence from randomized and observational studies. Lancet, 369 (9573), 1603-1613. 6. Greenwald, B. (2006). The DNA Stool Test - An Emerging Technology in Colorectal Cancer Screening. 7. Hamilton, S.R. (1985). Colorectal Carcinoma in patients with Crohns Disease. Gastroenterology, 89, 398-407. 8. Levin, K. E., and Dozois R. R. (1991). Department of Surgery, Mayo Clinic, Rochester, Minnesota 55905. Epidemiology of large bowel cancer. World J Surg., 15(5), 562-567. 9. Mosolits, S., Nilsson, B., and Mellstedt H. (2005). Towards therapeutic vaccines for colorectal carcinoma: a review of clinical trials. Expert Rev. Vaccines, 4, 329-350. 10. Park, Y., Hunter, D. J., Spiegelman, D., Bergkvist, L., Berrino, F., et al. (2005). Dietary fiber intake and risk of colorectal cancer: a pooled analysis of prospective cohort studies. JAMA, 294, 2849-2857. 11. Potter, J. D., and Mc Michael, A .J. (1986). Diet and cancer of the colon and rectum: A case-control study. Journal of the National Cancer Institute, 76(4), 557-569. 12. Su, L. J., and Arab, L. (2004). Alcohol consumption and risk of colon cancer: evidence from the National Health and Nutrition Examination Survey I Epidemiologic Follow-Up Study. Nutrition and Cancer, 50(2), 111–119. 13. Winawer, S. J., Zauber, A. G., Ho, M. N., OBrien, M. J., Gottlieb, L. S., Sternberg, S.S., et al. (1993). Prevention of colorectal cancer by colonoscopic polypectomy. The New England Journal of Medicine, 329, 1977-1981. 14. Wittekind, C. H., and Sobin, L. H. (2002). TNM classification of malignant tumours. New York: Wiley-Liss.  Read More