colorectal cancer (redirected from Adenocarcinoma, colon)

Colorectal cancer

Cancer of the large intestine, or colon, including the rectum (the last 16 in of the large intestine before the anus).

Mentioned in: Sigmoidoscopy

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colorectal cancer

[kō′lərek′təl]

Etymology: Gk, kolon, colon; L, rectus, straight

a malignant neoplastic disease of the large intestine, characterized by a change in bowel habits; the passing of blood (melena), which may be occult initially; and anemias. Malignant tumors of the large bowel usually occur after 50 years of age, are slightly more frequent in women than in men, and are common in the Western world. They are rare in children; clustering in families is common. The risk of large bowel cancer is increased in patients with chronic ulcerative colitis, villous adenomas, and especially familial adenomatous polyposis of the colon. 75% of all colorectal cancers have no known predisposing factors, but people who have a high-fat diet and low activity levels may be more likely than others to have this cancer. In the vermiform appendix, carcinoid is the most common tumor. Most lesions of the large bowel are adenocarcinomas. These tumors have a long preinvasive stage, and, when they invade, they tend to grow slowly. Rectal tumors may cause pain, bleeding, and a feeling of incomplete evacuation. They may metastasize slowly through lymphatic channels and veins and occasionally prolapse through the anus. Typical napkin ring tumors in the sigmoid and descending colon grow circumferentially and constrict the intestinal lumen, causing partial obstruction and production of flat or pencil-shaped stools. Manifestations include progressive abdominal distension, pain, vomiting, constipation, cramps, and bright red blood on the stool's surface. Malignant lesions in the ascending colon are usually large growths that may be palpable on physical examination; they generally cause severe anemia and nausea. There may be dark red or mahogany-colored blood mixed with the stool. The diagnosis of colorectal cancer is based on digital rectal examination, testing for blood in the stool, proctosigmoidoscopic examination of the sigmoid, and x-ray studies of the GI tract. Colonoscopy is the definitive test for colorectal cancer. Suspicious polyps may be removed for histologic study, often through a sigmoidoscope or colonoscope or by laparotomy. Surgical treatment of colorectal cancer may involve a wide resection of the lesion, the surrounding colon, and the attached tissues. Tumors of the rectum may require removal of the entire rectum by abdominoperineal resection and the creation of a permanent colostomy. Chemotherapy and irradiation may be administered as palliative therapy or adjuvant treatment. Nursing care of the patient after a diagnosis of colorectal cancer focuses on coping with a possible loss of or alteration in body function.

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colorectal cancer

Colon cancer Oncology A malignant epithelial tumor arising from the colonic or rectal mucosa, which is the 3^rd leading cause of cancer in ♂, 4^th ? in ♀ in the US; risk of CC is ↓ with a low fat, high fiber diet Epidemiology 152,000 new cases, 57,000 deaths–1993, US Surveillance Annual Fecal occult blood testing is reported to ↓ mortality by 33% Predisposition Adenomatous polyps, family Hx–highest if 1^st-degree family member–parents, siblings or children had CC and even higher if < age 55, ulcerative colitis Screening Most colorectal cancers develop from polyps; colon polypectomy ↓ CC; colon polyps and early cancer may be asymptomatic; screening is recommended every 3 yrs Clinical Rectal bleeding, occult blood in stools and, in advanced cases, bowel obstruction and weight loss Diagnosis Colonoscopy with biopsy, CT, barium enema Pathology Most CCs are adenocarcinomas; 'raromas' include lymphomas, neuroendocrine carcinomas, and sarcomas Molecular pathology CCs develop as genetic alterations accumulate–eg, K-ras oncogene on chromosome 12, and tumor-suppressor genes on chromosomes 5, 17p–which encodes p53, and 18q–DCC gene Management Surgery; cure likely if CA is confined to intestine. See Colorectal adenoma.

Colorectal cancer–TNM classification

Stage I Tumor invades muscularis propria, but has not spread to nearby lymph nodes

Stage II Tumor spread into the subserosa and/or perirectal tissues with up to 3 regional lymph nodes, or directly invades adjacent tissues without lymph node involvement

Stage III Any depth of tumor invasion with four or more positive lymph nodes, without distant metastases

Stage IV Any depth of tumor involvement; any number of involved lymp nodes, with distant metastases

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Patient discussion about Adenocarcinoma, colon.

Q. What is the best pathophysiology of colorectal cancer. The pathophysiology just has to be brief and concise. It also has to include nursing considerations for the patient.

A. i'm not sure i understand your question...do you mean what is the best treatment for colorectal cancer? patophysiology is the changes the tissue acquired. if you'll give me more details on what you are looking for i'll be more then happy to help you.