Colorectal cancer screening: an overview of available methods and current recommendations

BACKGROUND: Screening asymptomatic persons for colorectal cancer may decrease the incidence and mortality of this disease. METHODS: The MEDLINE database was used to identify articles addressing the rationale for colorectal cancer screening, methods used and their effectiveness, and current recommendations. RESULTS: Methods of screening for colorectal cancer include flexible sigmoidoscopy, fecal occult blood tests, barium enema, and colonoscopy. The method used and the frequency of screening are determined by assessing an individual's risk of having colorectal cancer. CONCLUSIONS: Colorectal cancer is a common malignancy in the United States, is curable when detected at an early stage, and is potentially preventable. The acceptance of colorectal cancer screening by patients and physicians has been suboptimal. while there remains little debate about the potential for screening to reduce mortality from colorectal cancer, debate continues about the cost-effectiveness of colorectal cancer screening when applied to the general population.     

Colon polyps and cancer

During 1999-2000, a number of important issues related to endoscopy and colorectal polyps and cancer were investigated. Several papers consider whether flat adenomas with high malignant potential are as common in the West as in Japan. Clinical series indicate that signs of rectal bleeding are more predictive of colorectal cancer than gastrointestinal symptoms. Colonoscopy is more accurate than double-contrast barium enema for detecting polyps, and virtual colonoscopy is a promising new diagnostic and screening technique. Primary prevention dietary studies using adenoma recurrence as an end point yield negative results. Surveillance colonoscopy protects individuals in families with hereditary nonpolyposis colorectal cancer, but gastroenterologists continue to perform cancer surveillance in patients with ulcerative colitis in an inconsistent manner. Screening for colorectal neoplasia with fecal occult blood tests and flexible sigmoidoscopy is being better defined and promoted, although many now advocate direct colonoscopy screening based on increasing indirect evidence of efficacy. Better methods of treating large sessile neoplasms are being developed and evaluated, and follow-up surveillance for adenoma patients increasingly is being tailored to individual patient risk.     

Colorectal cancer: risk factors and recommendations for early detection.

Spurred by mounting evidence that the detection and treatment of early-stage colorectal cancers and adenomatous polyps can reduce mortality, Medicare and some other payors recently authorized reimbursement for colorectal cancer screening in persons at average risk for this malignancy. A collaborative group of experts convened by the U.S. Agency for Health Care Policy and Research has recommended screening for average-risk persons over the age of 50 years using one of the following techniques: fecal occult blood testing each year, flexible sigmoidoscopy every five years, fecal occult blood testing every year combined with flexible sigmoidoscopy every five years, double-contrast barium enema every five to 10 years or colonoscopy every 10 years. Screening of persons with risk factors should begin at an earlier age, depending on the family history of colorectal cancer or polyps. These recommendations augment the colorectal cancer screening guidelines of the American Academy of Family physicians. Recent advances in genetic research have made it possible to identify persons at high risk for colorectal cancer because of an inherited predisposition to develop this malignancy. These patients require aggressive screening, usually by lower endoscopy performed at an early age. In some patients, genetic testing can guide screening and may be cost-effective.     

Non-small bowel lesion detection at small bowel capsule endoscopy: A comprehensive literature review

Small bowel capsule endoscopy is a minimally-invasive endoscopic investigation that is often used in clinical practice to investigate overt or occult gastrointestinal (GI) bleeding among other clinical indications. International guidance recommends small bowel capsule endoscopy as a first-line investigation to detect abnormalities in the small bowel, when gastroscopy and colonoscopy fail to identify a cause of GI bleeding. It can diagnose with accuracy abnormalities in the small bowel. However, there has been increasing evidence indicating that small bowel capsule endoscopy may also detect lesions outside the small intestine that are within the reach of conventional endoscopy and have been probably missed during prior endoscopic investigations. Such lesions vary from vascular deformities to malignancy and their detection often alters patient management, leading to further endoscopic and/or surgical interventions. The current study attempts to review all available studies in the literature and summarise their relevant findings.     

Prolonged rectal bleeding associated with hemorrhoids: the diagnostic contribution of colonoscopy

We studied 387 patients with prolonged rectal bleeding and hemorrhoids (grades 2 and 3) routinely examined by anoscopy, proctoscopy, single contrast barium enema, and hemoglobin measurements. Normal results were obtained in 86 patients above the age of 40. Total colonoscopy in these patients revealed one patient (1.2%) with cancer, 19 (22.1%) with colorectal polyps, and one (1.2%) with angiodysplasia. These findings indicate that in patients above age 40, a full investigation of the large bowel should be done in every case of prolonged rectal bleeding despite the presence of substantial hemorrhoids. Double contrast barium enema or colonoscopy must be used, rather than single contrast barium enema, which proved to be an inaccurate method of investigating prolonged rectal bleeding.     

多层螺旋CT在大肠癌诊断中的作用

目的 评价多层螺旋CT检查及后处理技术在大肠癌诊断中的作用。方法 85例经手术病理证实的大肠癌患者行大肠充气MSCT容积扫描和图像重建(包括MPR、MIP、SSD、Raysum和CTVE)，并与钡灌肠(80例)、结肠镜(60例)及手术结果进行比较。结果 所有病人的诊断符合率为100％，其三维重建与钡灌肠、CTVE与结肠镜的发现完全符合。结论 大肠充气MSCT检查及后处理技术能更好地反映大肠癌的病变和范围，明显优于单独应用X线钡灌肠或结肠镜检查。     

Invasive colorectal cancer detected up to 3 years after a colonoscopy negative for cancer

BACKGROUND AND STUDY AIMS: Colonoscopy has replaced barium enema as the primary method for direct diagnosis of colorectal cancer, but detection may fail, and the reasons for this are not completely understood. PATIENTS AND METHODS: In order to analyze the accuracy of colonoscopy for detecting invasive colorectal cancer, 7365 colonoscopic examinations were matched with the most accurate local government population-based cancer registry in Japan. RESULTS: In 15 colonoscopic examinations, patients were not diagnosed as having invasive colorectal cancer, but disease of this type was detected within 3 years of the examinations (false-negative examinations). During the same period, 233 colonoscopies were identified as true-positive examinations. The false-negative rate for detecting invasive colorectal cancer with colonoscopy was 6% at 3 years. The false-negative rate was significantly higher in individuals between 60 and 69 years of age and in invasive cancers located to the right of the splenic flexure. CONCLUSIONS: Colonoscopists should receive adequate training in achieving easy cecal intubation, detecting small or flat lesions, and carrying out adequate biopsies.     

右半结肠癌延误诊断的原因分析

目的：减少右半结肠癌的误诊和漏诊。方法：分析我院结肠镜检查证实的右半结肠癌患者的病史，了解在诊断过程中有无误诊或漏诊发生，分析其原因。结果：共有32例在结肠镜检查明确诊断前存在漏诊或误诊，诊断为急性阑尾炎9例，慢性阑尾炎5例．阑尾周围脓肿6例，贫血、粘连性肠梗阻和慢性结肠炎各2例，十二指肠溃疡和慢性胆囊炎各1例。钡灌肠和结肠镜检查漏诊各2例。结论：仔细询问病史，对于右侧腹痛、腹块、便血、贫血等症状的患者要想到右半结肠癌的可能，尽早行钡灌肠或肠镜检查，检查阴性但临床上仍怀疑时，应重复检查避免漏诊。     

Colorectal cancer screening

Colorectal cancer causes significant morbidity and mortality in the United States. The incidence of colorectal cancer increases at age 50, approximately. Risk factors that have been identified include a personal history of colorectal cancer or adenomas, a family history of colon cancer or adenomas, inherited colorectal cancer syndromes, and long standing inflammatory bowel disease. Several screening tests have been developed for colorectal cancer prevention. Surveillance strategy is based on an individual's colorectal cancer risk. This article reviews fecal occult blood testing, flexible sigmoidoscopy, colonoscopy, barium enema, and genetic testing.     

Reasons for failure to diagnose colorectal carcinoma at colonoscopy

BACKGROUND AND STUDY AIMS: Colonoscopy can produce false-negative results, and the reasons for this remain obscure. The aim of this study was to examine why cancers are missed at colonoscopy. PATIENTS AND METHODS: All colonoscopies carried out at Christchurch Hospital, New Zealand, over a 43-month period (1 October 1997 - 30 April 2001) were retrospectively analyzed (the data having been prospectively collected). All cases of colorectal carcinoma during the period 1 October 1997 - 30 July 2001 (3 months longer, to capture delayed diagnoses) were also identified. The two databases were then compared, and all cases in which a colonoscopy had been performed more than 6 weeks before a colorectal carcinoma specimen being received by the pathology department were identified and analyzed. RESULTS: A total of 5055 colonoscopies were undertaken in 4598 patients. Over this period, 630 colorectal carcinomas were identified in the pathology database; 286 of the patients affected were in the colonoscopy and pathology database. Sixty-six patients had had a colonoscopy performed more than 6 weeks before the diagnosis of colorectal carcinoma. Carcinoma was identified in 48 of these 66 patients, and management was being provided. Seventeen cancers (5.9 %) were missed at colonoscopy, and the patients had had an incomplete colonoscopy in nine of these cases. In seven of the 17, an alternative benign cause was recorded. In four patients, a lesion was seen and thought to be benign, although subsequently proven not to be. In another four cases, the cancer was not diagnosed despite adequate bowel preparation and what was thought by the colonoscopist to be an adequate colonoscopy. CONCLUSIONS: Colonoscopy missed 17 of 286 cancers (5.9 %). The reasons why cancers were missed relate to incomplete colonoscopy, poor bowel preparation, misinterpretation of what was seen, failure to carry out adequate biopsy (and follow-up) of lesions seen, and systems failures related to follow-up investigations in patients who had an incomplete colonoscopy. The fact that colonoscopy and barium enema investigations may fail to diagnose cancers has important medicolegal implications. The recognition that colonoscopy may miss a cancer should encourage doctors to reinvestigate patients when there is a lack of correlation between the clinical and investigative findings.     

双对比造影诊断上胃肠道肿瘤的价值再认识

目的：探讨双对比造影在当前医疗过程中是否对上胃肠道肿瘤仍为基本的诊断手段。材料和方法：回顾性分析1991－1997年来我院临床初诊为上消化道疾病并作双对比造影检查的11840病例，其中胃镜及活检阴性的肿瘤59例，评价双对比造影对上消化道肿瘤的诊断价值。结果：检出肿瘤总数为3443人次，检出率29．1％，其中恶性肿瘤3435例，占肿瘤的99．7％，包括食管癌2708例（78．9％），胃癌701例（20％），十二指肠空肠近段肿瘤34例（1％）。早癌55例，检出率1．6％，多重癌17例，为0．5％。临床内镜及活检阴性的59例肿瘤中，食管癌17例，贲门癌20例，浸润型胃癌11例，溃疡性胃癌5例，空肠癌6例，其中被钡剂双对比检查诊断57例，准确率97．8％。结论：双对比造影仍然是上胃肠道肿瘤敏感的诊断技术，尤其对粘膜下浸润，以管腔狭窄为主的病变以及胃贲门、空肠近侧段的肿瘤诊断具有优势。     

International digestive endoscopy network 2012: a patchwork of networks for the future

This special September issue of Clinical Endoscopy will discuss various aspects of diagnostic and therapeutic advancement of gastrointestinal (GI) endoscopy, explaining what is new in digestive endoscopy and why international network should be organized. We proposed an integrated model of international conference based on the putative occurrence of Digestive Endoscopy Networks. In International Digestive Endoscopy Network (IDEN) 2012, role of endoscopy in gastroesophageal reflux disease and Barrett's esophagus, endoscopy beyond submucosa, endoscopic treatment for stricture and leakage in upper GI, how to estimate the invasion depth of early GI cancers, colonoscopy in inflammatory bowel disease (IBD), a look into the bowel beyond colon in IBD, management of complications in therapeutic colonoscopy, revival of endoscopic papllirary balloon dilation, evaluation and tissue acquisition for indeterminate biliopancreatic stricture, updates in the evaluation of pancreatic cystic lesions, issues for tailored endoscopic submucosal dissection (ESD), endoluminal stents, management of upper GI bleeding, endoscopic management of frustrating situations, small bowel exploration, colorectal ESD, valuable tips for frustrating situations in colonoscopy, choosing the right stents for endoscopic stenting of biliary strictures, advanced techniques for pancreaticobiliary visualization, endoscopic ultrasound-guided biliopancreatic drainage, and how we can overcome the obstacles were deeply touched. We hope that IDEN 2012, as the very prestigious endoscopy networks, served as an opportunity to gain some clues for further understanding of endoscopic technologies and to enhance up-and-coming knowledge and their clinical implications from selected 25 peer reviewed articles and 112 invited lectures.     

上消化道黏膜下肿瘤内镜下诊治分析

目的：探讨内镜在上消化道黏膜下肿瘤诊断及治疗中的应用价值。方法：内镜结合超声内镜进行临床诊断，高频电切及其它方法对直径小于2cm良性肿瘤行内镜下治疗。结果：48例内镜治疗后病理确诊黏膜下肿瘤，仅6例术前活检病理确诊，21例术前接受超声胃镜检查，其中16例与术后病理符合。47例1次切除，1例2次以上切除。单纯高频电切除24例，皮圈或尼龙圈套扎后切除12例，血管瘤栓塞和套扎治疗2例，黏膜切除术10例，均未发生严重并发症。结论：黏膜下肿瘤术前诊断主要依据形态学，超声胃镜可判断肿瘤起源层次，确诊有赖术后病理。内镜下治疗对机体损伤小，并发症少。为较小黏膜下肿瘤治疗首选方法。     

Screening for colorectal cancer. Guidelines for choosing the appropriate test for each patient

The importance of screening for colorectal cancer has been established, but the decision about which test to use for each patient may seem less clear. In this article, Dr Wineman discusses assessment of colorectal cancer risk and the advantages and disadvantages of the fecal occult blood test, flexible sigmoidoscopy, double-contrast barium enema, and colonoscopy. Potential screening methods that could make regular colon examination more acceptable to patients also are presented.     

Fiberoptic colonoscopic examination in surgical patients with colorectal cancer

A diagnostic and surveillance program using colonscopy in patients with colorectal cancer was established at North Carolina Memorial Hospital. The records of all patients who had preoperative or postoperative colonoscopic examination between 1976 and 1979 were reviewed. Fifty-five patients had colonscopic examination preoperatively. No additional disease was found in 39. In 15 patients, unsuspected additional disease was detected, and one patient had a suspected polyp ruled out by colonoscopic examination. One of these patients was found to have a synchronous primary cancer, not demonstrated by barium enema. Surgical treatment was modified in nine (16%) of these 55 patients by the preoperative colonoscopic findings. Sixty patients had colonoscopy six months to six years postoperatively. No additional disease was found in 47. Adenomatous polyps were found in eight. Two patients had recurrent cancer proved by colonoscopy, and three had a second primary cancer detected only by colonoscopy. Treatment was directly influenced by colonoscopy in eight (13.3%) of these 60 patients. These studies had a favorable cost/benefit ratio in patients with colorectal cancer and support a program of preoperative colonoscopy in patients with colorectal cancer and reexamination within two to three years after operation.     

Colorectal cancer in patients 20 years old or less in Taiwan.

BACKGROUND: Colorectal cancer (CRC) is predominantly a disease of the elderly population, but it sometimes occurs in young patients. The diagnosis of CRC in youngsters is often overlooked by physicians or presentation may be delayed. METHODS: With assistance from the cancer registry center of Taipei Veterans General Hospital, we collected data on all types of colorectal malignancy, including carcinoma, adenocarcinoma, or lymphoma in patients aged 20 or younger. All available medical charts and pathologic specimens were reviewed in detail. RESULTS: A total of 28 cases were analyzed. The leading presenting symptom was abdominal pain (92%). The locations of the primary tumors were evenly distributed, and the major histologic type was predominantly adenocarcinoma. However, the proportion of mucinous adenocarcinoma was higher than that in the older population. Most of the cases were advanced (11 tumors were classified as Dukes stage C and another 11 as Dukes stage D). The overall 5-year survival rate was 21%. CONCLUSIONS: Despite the rarity of CRC during the first two decades of life, physicians need to be aware of the possibility and to evaluate suggestive signs and symptoms by colonoscopy or barium enema. Family history of CRC, inflammatory bowel disease, previous polyps, or familial polyposis did not play a crucial role in this group of young patients.     

Colonoscopically detected colorectal cancer missed on barium enema

The radiographs and clinical records of 26 patients with colorectal cancer missed on barium enema, and subsequently detected at colonoscopy, were reviewed to determine the cause of radiological error. Twenty (77%) of the patients were female. In 24 of 26 patients, anemia and/or rectal bleeding was a presenting feature. Fourteen of the 26 (54%) missed cancers were in the sigmoid colon, 10 (38%) in the ascending colon or hepatic flexure, and two (8%) in the rectum. Tumor size ranged from 20–100 mm. Fifteen were polyps, and 11 annular cancers. Fourteen (54%) were Dukes C or D tumors. Twenty-eight barium enemas in 23 patients were available for review: 86% were double-contrast studies. In 18 (76%), the cancer could be seen in retrospect and, in over half, the tumor was obvious. The dominant perceptive error was due to missing the lesion in the barium pool. Other major errors were missing the lesion en face or in overlapping loops. As most cancers were missed because of observer perceptive error, by both experienced and inexperienced radiologists, the authors recommend double reporting of all barium enemas.     

Evaluation of the PillCam Colon capsule in the detection of colonic pathology: results of the first multicenter, prospective, comparative study

BACKGROUND AND STUDY AIMS: Population-based screening for colorectal cancer is widely recommended, with conventional colonoscopy considered to be the preferred diagnostic modality. However, compliance with screening colonoscopy is low and manpower capacity is limited. Capsule endoscopy might therefore represent a desirable alternative strategy. PATIENTS AND METHODS: The PillCam Colon capsule endoscope was prospectively tested in a multicenter setting. The indications for endoscopy in the enrolled patients included colorectal cancer screening (43 %), postpolypectomy surveillance (26 %), and lower gastrointestinal signs and symptoms (31 %). Study subjects underwent colon preparation and then ingested the capsule on the morning of the examination, with conventional colonoscopy being performed the same day. The PillCam Colon capsule findings were reviewed by three experts in capsule endoscopy who were blinded to the conventional colonoscopy findings. RESULTS: A total of 91 subjects were enrolled in three Israeli centers (55 men, 36 women; mean age 57), and the results were evaluable in 84 cases. The capsule was excreted within 10 hours in 74 % of the patients and reached the rectosigmoid colon in the other 16 %. Of the 84 evaluable patients, 20 (24 %) had significant findings, defined as at least one polyp of 6 mm or more in size or three or more polyps of any size: 14/20 (70 %) were identified with the capsule and 16/20 (80 %) were identified by conventional colonoscopy. Polyps of any size were found in 45 patients, 34/45 (76 %) found by the capsule and 36/45 (80 %) by conventional colonoscopy. In comparison with conventional colonoscopy, false-positive findings on PillCam Colon capsule examination were recorded in 15/45 cases (33 %). There were no adverse events related to the capsule endoscopy. CONCLUSIONS: PillCam Colon capsule endoscopy appears to be a promising new modality for colonic evaluation. Further improvements in the procedure will probably increase capsule examination completion and polyp detection rates. Additional studies are needed to evaluate the accuracy of PillCam Colon endoscopy in other patient populations with different prevalence levels of colonic disease.     

Gastrointestinal hemorrhage in paralyzed and neurologically impaired patients: Contribution of reflux esophageal disease

The role of gastroesophageal reflux (GER) and reflux esophagitis in the pathogenesis of gastrointestinal hemorrhage was assessed in 13 male patients with chronic paralysis or neurologic impairment. Nine of the 13 patients initially presented for barium meal examination to evaluate anemia, hematemesis, heme-positive stools, or melena. Six of the 9 had radiographic evidence, confirmed by upper gastrointestinal (GI) endoscopy, of esophagitis with or without stricture without other upper GI tract lesions. Notably absent were antecedent symptoms of GER such as heartburn or dysphagia. Careful examination of the esophagus, although difficult, must be an integral part of the evaluation for anemia and/or gastrointestinal blood loss in paralyzed patients.     

Update on colorectal cancer. Risk factors, diagnosis, and treatment

Colorectal cancer is more common in the Western world than in underdeveloped countries. Diet, longevity, heredity, and presence of other bowel diseases may affect the incidence. Diagnosis is based on results of routine laboratory studies and evaluation of the entire large bowel with air-contrast barium enema and colonoscopy. Surgical resection is the primary therapy for colorectal cancer. Postoperative systemic chemotherapy yields poor results, but hepatic artery infusional chemotherapy offers some benefit to patients who have only hepatic metastases. Follow-up evaluation includes physical examination and laboratory studies every 3 months for the first 2 years and colonoscopy every year.