| 单词 | colorectal cancer | ||||||||||||||||||||||||||||||||||||
| 释义 | colorectal cancercolorectal cancercolorectal cancerA malignant epithelial tumour arising from the colonic or rectal mucosa. It is the 3rd leading cause of cancer in the US. The risk of colorectal cancer (CRC) is reduced with a low-fat, high-fibre diet.Epidemiology 139,000 new cases, 53,000 deaths (2006, US). Clinical findings Rectal bleeding, occult blood in stools and, if advanced, bowel obstruction and weight loss. Surveillance Most CRCs develop from polyps which, like early cancer, are often asymptomatic. Screening is recommended every 3 years; annual faecal occult blood testing is reported to reduce mortality by 33%, as cancers are detected earlier. Predisposition Adenomatous polyps, family history—highest if 1st-degree family member (parents, siblings or children) had CRC, and even higher if it occurred under age 55, or there’s a history of ulcerative colitis. Diagnosis Colonoscopy with biopsy, CT, barium enema. Management Surgery; cure likely if cancer is confined to intestine. Colorectal cancer—TNM staging Stage I: Tumour invades muscularis propria, but no spread to nearby lymph nodes. Stage II: Tumour spreads into the subserosa and/or perirectal tissues with up to 3 regional lymph nodes, OR directly invades adjacent tissue without lymph node involvement. Stage III: Any depth of tumour invasion with 4+ positive lymph nodes; no distant metastases. Stage IV: Any depth of tumour invasion; any number positive lymph nodes, distant metastases. colorectal cancerColon cancer Oncology A malignant epithelial tumor arising from the colonic or rectal mucosa, which is the 3rd leading cause of cancer in ♂, 4th ? 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 1st-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 cancerColorectal Cancer
Colorectal cancer accounts for about 15% of all malignancies and for about 11% of cancer mortality in both men and women living in the United States, is the third most commonly diagnosed cancer in the United States, and is the second leading cause of death from malignancy. Approximately 50,000 Americans die each year from colorectal cancer. In recent years, both the incidence and the mortality rates have shown a decline, and this is attributed to early identification and improved treatment measures. In 2013, a total of 102,480 new cases of colon cancer and 40,340 new cases of rectal cancer were diagnosed in the United States. The lifetime risk of colorectal cancer is 5.4%, and the 5-year survival rate is 90% if it is diagnosed at an early stage. Unfortunately, only 39% of the cases are identified early. The 5-year survival rate drops to 10% if the colorectal cancer spreads to distant organs and lymph nodes. Of cancers of the colon, 65% occur in the rectum and in the sigmoid and descending colon, 25% occur in the cecum and ascending colon, and 10% occur in the transverse colon. Most colorectal tumors (95%) are adenocarcinomas and develop from an adenomatous polyp. Once malignant transformation within the polyp has occurred, the tumor usually grows into the lumen of the bowel, causing obstruction, and invades the deeper layers of the bowel wall. After penetrating the serosa and the mesenteric fat, the tumor may spread by direct extension to nearby organs and the omentum. Metastatic spread through the lymphatic and circulatory systems occurs most frequently to the liver as well as the lung, bones, and brain. CausesThe cause of colorectal cancer is largely unknown; however, there is much evidence to suggest that incidence increases with age. Risk factors include a family history of colorectal cancer and a personal history of past colorectal cancer, ulcerative colitis, Crohn’s disease, or adenomatous colon polyps. Persons with familial polyposis coli, an inherited disease characterized by multiple (> 100) adenomatous polyps, possess a risk for colorectal cancer that approaches 100% by age 40. Other risk factors include obesity, diabetes mellitus, alcohol usage, night shift work, and physical inactivity. It has been strongly suggested that diets high in fat and refined carbohydrates play a role in the development of colorectal cancer. High-fat content results in increased amounts of fecal bile acid. It is hypothesized that intestinal bacteria react with the bile salts and facilitate carcinogenic changes. In addition, fat and refined carbohydrates decrease the transit of food through the gastrointestinal (GI) tract and increase the exposure of the GI mucosa to carcinogenic substances that may be present. Recent research indicates that aspirin, cytochrome C oxidase (COX)-2 selective NSAIDs, folate, calcium, and estrogen replacement therapy have a potential chemoprotective effect and may prevent colorectal cancer. Genetic considerationsAbout 75% of colorectal cancers are sporadic; another 25% clearly have genetic contributions. Hereditary nonpolyposis colorectal cancer (HNPCC) accounts for 5% to 10% of colorectal cancer cases overall. Families with HNPCC have a lifetime risk of getting colorectal cancer between 70% and 90%, which is several times the risk in the general population. Colon cancer is also highly penetrant in familial adenomatous polyposis (FAP), which is caused by mutations in the tumor suppressor adenomatous polyposis coli (APC). FAP represents about 1% of all colorectal cancer cases. Mutations in several genes, including MLH1, MSH2, and MSH6, have been linked to HNPCC, for which genetic testing is available. Other genetic risk factors remain unidentified. Gender, ethnic/racial, and life span considerationsColorectal cancer affects men slightly more than women. The incidence of colorectal cancer is exceeded only by lung cancer in both men and women and by prostate cancer in men and breast cancer in women. There is a slight predominance of colon cancer in women and rectal cancer in men. The incidence increases after age 40 and begins to decline between ages 65 and 75, although 90% of all newly diagnosed cancers are in people older than 50. Colorectal cancer can be diagnosed in individuals of any age, but malignancies that occur around age 20 to 30 are usually difficult to control and signify a poor prognosis. It is also more common in persons of Jewish or Eastern European descent. It is associated with gastric cancer in people with Asian ancestry. Black/African American people have a higher incidence of rectal cancer and higher death rates than non-Hispanic white people and Hispanic people. Global health considerationsColorectal cancer is the fourth most common cancer diagnosis around the globe. Approximately 700,000 people die each year from colorectal cancer. Developed nations in North America, Australia, and Western Europe, along with Israel and Japan, have an 8 to 10 times higher incidence of the disease than developing nations such as China, Algeria, and India. These differences may be associated with cultural differences in diet and patterns of cigarette smoking, alcohol use, and exercise. AssessmentHistorySeek information about the patient’s usual dietary intake, family history, and the presence of the other major risk factors for colorectal cancer. A change in bowel pattern (diarrhea or constipation) and the presence of blood in the stool are early symptoms and might cause the patient to seek medical attention. Patients may report that the urge to have a bowel movement does not go away with defecation. Cramping, weakness, and fatigue are also reported. As the tumor progresses, symptoms develop that are related to the location of the tumor within the colon. When the tumor is in the right colon, the patient may complain of vague cramping or aching abdominal pain and report symptoms of anorexia, nausea, vomiting, weight loss, and tarry-colored stools. A partial or complete bowel obstruction is often the first manifestation of a tumor in the transverse colon. Tumors in the left colon can cause a feeling of fullness or cramping, constipation or altered bowel habits, acute abdominal pain, bowel obstruction, and bright red bloody stools. In addition, rectal tumors can cause stools to be decreased in caliber, or “pencil-like.” Depending on the tumor size, rectal fullness and a dull, aching perineal or sacral pain may be reported; however, pain is often a late symptom. Physical examinationRectal bleeding, blood stool, and changes in bowel habits are the most common symptoms. Inspect, auscultate, and palpate the abdomen. Note the presence of any distention, ascites, visible masses, or enlarged veins (a late sign due to portal hypertension and metastatic liver involvement). Bowel sounds may be high-pitched, decreased, or absent in the presence of a bowel obstruction. An abdominal mass may be palpated when tumors of the ascending, transverse, and descending colon have become large. Note the size, location, shape, and tenderness related to any identified mass. Percuss the abdomen to determine the presence of liver enlargement and pain. A rectal tumor can be easily palpated as the physician performs a digital rectal examination. PsychosocialIndividuals who observe healthy lifestyles may feel anger when the diagnosis is made. Treatment for colorectal cancer can result in a colostomy and impotence in men. Many persons have grave concerns about the possibility of these consequences. Assess the patient and his or her significant others’ knowledge and feelings related to these issues. Diagnostic highlightsGeneral Comments: Pathological results from biopsied tissues provide the definitive diagnosis for cancer.
Other Tests: Complete blood count, barium enema, computed tomography scan, magnetic resonance imaging, and abdominal x-rays to determine abdominal obstruction Primary nursing diagnosisDiagnosisPain related to tissue injury from tumor invasion and the surgical incisionOutcomesComfort level; Pain control behavior; Pain level; Pain: Disruptive effectsInterventionsPain management; Analgesic administration; Anxiety reduction; Environmental management: Comfort; Patient-controlled analgesiaPlanning and implementationCollaborativeAlthough treatment depends on individual patient characteristics, the location of the tumor, and the stage of disease at the time of diagnosis, surgery has been the primary treatment for colorectal cancers. Staging is generally done by the TNM system (T: tumor, N: nodes, M: metastasis) or the modified Duke staging system. Adjuvant chemotherapy and radiation therapy may be used to improve survival or control symptoms. The exact surgical procedure performed depends on the location of the tumor in the colon, the amount of tissue involved, and patient's decisions about preservation of function. When deciding about the nature of surgery, several important considerations exist, including assessment of the likelihood of cure, preservation of anal continence (sphincter-saving procedures are standard of care for colorectal cancer patients), and preservation of genitourinary functions. preoperative.All patients who are undergoing bowel surgery require careful preoperative care in order to minimize the possibility of infection and promote the adjustment to bodily changes. If nutritional deficits are present, a low-residue diet high in calories, carbohydrates, and protein is given until serum electrolytes and protein levels return to normal. Total parenteral nutrition may be ordered. Twenty-four hours before the scheduled surgery, the physician usually orders a “bowel prep,” which consists of a clear liquid diet, a regimen of cathartics and cleansing enema, and oral and intravenous antibiotics to minimize bacterial contamination during surgery.postoperative.Postoperatively, direct nursing care toward providing comfort, preventing complications from major abdominal surgery, and promoting the return of bowel function. Monitor vital signs and drainage from wounds and drains for signs of hemorrhage and infection. A nasogastric tube connected to low intermittent or continuous suction is usually present for gastric decompression until bowel sounds return. Note the amount and color of the gastric drainage, as well as the presence of abdominal distention.Patients who require a colostomy return from surgery with an ostomy pouch system in place as well as a large abdominal dressing. Observe the condition of the stoma every 4 hours. A healthy stoma is beefy red and moist, whereas a dusky appearance could indicate stomal necrosis. A small amount of stomal bleeding is common, but any substantial bleeding should be reported to the surgeon. The colostomy usually begins to function 2 to 4 days after surgery. After surgery, adjuvant radiation therapy to the abdomen or pelvis is used when there is high risk for local recurrence. Adjuvant chemotherapy (5-fluorouracil plus leucovorin) is used when there is high risk or evidence of metastatic disease. Radiation therapy and chemotherapy may be used as palliative measures to reduce pain, bleeding, or bowel obstruction in patients with advanced and metastatic disease. Pharmacologic highlights
IndependentEncourage the patient to verbalize fears and clarify the physician’s explanation of diagnostic results. Dispel any misconceptions about the need for a permanent colostomy and clarify the purpose of a temporary colostomy if suggested. If a colostomy is to be performed, encourage the patient and her or his significant other to verbalize concerns about sexual functioning after surgery. Encourage active participation of the patient and family in surgical decisions. Impotence is only a problem after abdominal perineal resection (APR) in men, but the presence of a stoma and a drainage pouch with fecal effluent can affect self-identity and sexual desires in both men and women. After surgery, discuss methods to decrease the impact of the ostomy during intimate times. After surgery, help the patient avoid complications associated with bowel surgery. Assist the patient to turn in bed and perform coughing, deep breathing, and leg exercises every 2 hours to prevent skin breakdown as well as to avoid pulmonary and vascular stasis. Teach the patient to splint the abdominal incision with a pillow to minimize pain when turning or performing coughing and deep-breathing exercises. The patient who has had an APR may find the side-lying position in bed the most comfortable. Provide a soft or “waffle” pillow (not a rubber doughnut) for use in the sitting position. Change the perineal dressing frequently to prevent irritation to the surrounding skin. Showing the patient pictures of an actual stoma can help reduce the “shock” of seeing the stoma for the first time. Allow him or her to hold the equipment, observe the amount and characteristics of effluent, and empty the ostomy pouch of contents or gas. When emptying or changing the pouch system, take care to not contaminate the abdominal incision with effluent. Teaching the patient about home care of an ostomy can begin on the second or third postoperative day. Have the patient and a family member demonstrate ostomy care correctly before hospital discharge. Be alert to signs that indicate the need for counseling, and suggest a referral if the patient is not adjusting well. Evidence-Based Practice and Health PolicyCho, E., Lee, J.E., Rimm, E.B., Fuchs, C.S., & Giovannucci, E.L. (2012). Alcohol consumption and the risk of colon cancer by family history of colorectal cancer. American Journal of Clinical Nutrition, 95(2), 413–419.
Documentation guidelines
Discharge and home healthcare guidelinespatient teaching.Teach the patient the care related to the abdominal incision and any perineal wounds. Give instructions about when to notify the physician (if the wound separates or if any redness, bleeding, purulent drainage, unusual odor, or excessive pain is present). Advise the patient not to perform any heavy lifting (> 10 lb), pushing, or pulling for 6 weeks after surgery. If the patient has a perineal incision, instruct her or him not to sit for long periods of time and to use a soft or waffle pillow rather than a rubber ring whenever in the sitting position.Teach the patient colostomy care and colostomy irrigation. Give the following instructions for care of skin in the external radiation field: Tell the patient to wash the skin gently with mild soap, rinse with warm water, and pat the skin dry each day; not to wash off the dark ink marking that outlines the radiation field; to avoid applying any lotions, perfumes, deodorants, and powder to the treatment area; to wear nonrestrictive soft cotton clothing directly over the treatment area; and to protect skin from sunlight and extreme cold. Explain the purpose, action, dosage, and side effects of all medications prescribed by the physician. follow-up.Stress the need to maintain a schedule for follow-up visits recommended by the physician. Encourage patients with early-stage disease and complete healing of the bowel to eat a diet consisting of a low-fat and high-fiber content with cruciferous vegetables (Brussels sprouts, cauliflower, broccoli, cabbage).Most colorectal tumors grow undetected as symptoms slowly develop. Survival rates are best when the disease is discovered in the early stages and when the patient is asymptomatic. Unfortunately, 50% of patients have positive lymph node involvement at the time of diagnosis. Participation in procedures for the early detection of colorectal cancer needs to be encouraged. Suggest follow-up involvement with community resources such as the United Ostomy Association and the American Cancer Society. Patient discussion about colorectal cancerQ. 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. See CONUS Replacement Center |
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