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PubMed1997

[Virtual CT colonoscopy. Examination technique, limitations and perspectives].

Virtual CT-colonoscopy is a post-processing method which allows for reconstruction of inner bowel surface structures from helical CT datasets. The reconstructed images simulate the views which are known from fiberoptic endoscopy. Since colorectal cancer is the second main cause of death in USA and Europe today and since recent screening recommendations are often ignored by the public, a non-invasive or minimal-invasive procedure for colonic evaluation would offer some benefits. Virtual CT-colonoscopy generally involves three essential steps: patient preparation with cleansing of the bowel and administration of an air enema, helical CT-examination by using appropriate scan parameters, and interactive 3D rendering of the volume data-set. Although recent studies have demonstrated that polypoid lesions of about 5 mm size are well detectable and although virtual colonoscopy offers many advantages over fiberoptic endoscopy, some technical and clinical limitations must still be noted. Thus, the current inability of virtual colonoscopy to provide texture and color leads to problems in identifying flat lesions; the presence of retained or adherent fecal matter may result to false positive diagnosis and collapsed segments of bowel may cause problems as they cannot subsequently be evaluated during image reconstruction. Virtual endoscopy is still in its infancy and further technical and clinical developments are necessary. Virtual CT-colonoscopy may then prove to be equal or superior to colonoscopy in sensitivity and specificity for polyp detection and be able to reduce the number of unnecessary colonoscopic procedures.

Colonoscopes↗

PubMed2026

Comparative Efficacy of Different AI Systems for Polyp Detection by Size During Colonoscopy: Systematic Review and Network Meta-Analysis.

BACKGROUND: Colorectal cancer remains a leading cause of death despite being largely preventable through polypectomy. AI systems designed to enhance polyp detection during colonoscopy have shown promise, but the extent to which they improve detection of different-sized polyps remains unclear. OBJECTIVE: This study compared the size-stratified efficacy of AI-assisted colonoscopy vs standard colonoscopy using the Hartung-Knapp-Sidik-Jonkman (HKSJ) method, and generated exploratory rankings while acknowledging all cross-platform comparisons are indirect. METHODS: This systematic review and network meta-analysis (NMA) searched PubMed, Embase, Cochrane CENTRAL, and Web of Science from inception to July 25, 2026, supplemented by citation searching. We included randomized controlled trials (RCTs) comparing AI-assisted vs standard colonoscopy in adults (≥18 years of age), reporting mean polyp detection counts stratified by size (≤5 mm, 6-9 mm, and ≥10 mm). Two reviewers screened studies, extracted data, and assessed risk of bias using the Cochrane Risk of Bias 2.0. We conducted frequentist NMA using the HKSJ method with restricted maximum likelihood estimation, calculated 95% prediction intervals (PIs), and assessed heterogeneity using I2 and τ2. Certainty of evidence was rated using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) framework. RESULTS: A total of 13 RCTs (4156 participants) compared 8 AI systems to standard colonoscopy, forming a network without direct AI comparisons. For diminutive polyps (≤5 mm), AI showed a modest advantage (standardized mean difference [SMD] 0.21, 95% CI 0.07 to 0.35, 95% PI -1.12 to 1.54), but substantial heterogeneity (I2=86.6%) and wide PI crossing the null indicated high uncertainty. EndoScreener showed the most consistent evidence (SMD 0.36, 95% CI 0.18-0.54). For small and large polyps, effects were minimal (SMD 0.02, 95% CI -0.02 to 0.06, 95% PI -0.03 to 0.07; SMD 0.01, 95% CI 0.00-0.02, 95% PI -0.01 to 0.03). GRADE certainty was very low for diminutive polyps and low for small and large polyps. Sensitivity analysis excluding Tianjin YuJin did not materially change findings. CONCLUSIONS: AI may modestly enhance diminutive polyp detection, but effects on small and large polyps are minimal, with no platform superiority. Given very low to low certainty, findings are hypothesis-generating. This exploratory NMA provides size-stratified comparisons that can inform future head-to-head trial design. Unlike prior reviews aggregating all polyp sizes, we show the overall AI benefit is driven by diminutive polyp detection, providing a framework for targeted deployment-prioritizing AI for diminutive polyp screening, with limited value for larger lesions. Head-to-head trials are urgently needed. TRIAL REGISTRATION: PROSPERO International Prospective Register of Systematic Reviews CRD420251266932; https://www.crd.york.ac.uk/PROSPERO/view/CRD420251266932.

Colonoscopy↗

PubMed1987

A study of patient acceptance of double-contrast barium enema and colonoscopy. Which procedure is preferred by patients?

To our knowledge, no previous study has addressed the question of which method of evaluation of the lower gastrointestinal tract is preferred by patients, air-contrast barium enema or colonoscopy. Over a four-month period, we asked 189 consecutive patients who had undergone colonoscopy to express their preference for either air-contrast barium enema or colonoscopy. A clear preference for colonoscopy was expressed by our patients in terms of comfort and polyp detection despite higher cost. Time lost from work and post-procedure constipation were significantly less for colonoscopy than for barium enema. These factors should be considered in the evaluation of suspected lower gastrointestinal tract disease.

Adult↗

PubMed1986

Colonoscopy after curative resection of colorectal cancer.

Colonoscopy is generally considered to be an important part of the follow-up program for patients who have undergone curative resection of colorectal cancer. However, there are few data available concerning the frequency with which colonoscopy should be performed and for what length of time after operation. Since 1978, our policy has been to examine the colon annually in these patients using colonoscopy alternating with barium enema. We have evaluated the results in 100 patients over a four-year period. Based on size and histology, the significant colonoscopic findings were new colon cancers in three patients and 11 polyps demonstrating increased risk for malignancy in nine patients. This represents an interval yield of 3% per year. From these results and other reports, we recommend that these patients undergo total colonoscopy in the perioperative period to identify and remove synchronous lesions of the colon, and that examination of the remaining colon should be performed annually, preferably with colonoscopy, for at least the first four years after curative resection.

Barium Sulfate↗

PubMed1989

Rationale for aggressive colonoscopy in patients with colorectal neoplasia.

The role of colonoscopy in patients with colorectal neoplasia is not well established. The results of colonoscopy, from 1982 through 1987, in 42 patients with cancers who underwent preoperative colonoscopy (group 1), 64 patients with benign polyps (group 2), and 51 patients who were examined only postoperatively (group 3) were reviewed. These results indicated that (1) approximately one third of all findings would have been missed if endoscopy had been performed to only 60 cm; (2) there was a high incidence of synchronous lesions (33.3%) in group 1 and 34.4% in group 2); (3) 57% of patients with synchronous cancer and 63.6% of patients with synchronous polyps developed metachronous lesions, compared with 10.7% and 11.9% of patients with a single lesion; (4) there was a higher incidence of metachronous lesions seen in group 3, compared with group 1; and (5) the median interval for noting metachronous lesions in patients who underwent colonoscopy preoperatively was approximately 18 months. These findings endorsed preoperative colonoscopy and aggressive follow-up in patients with colorectal tumors.

Adult↗

PubMed1995

The utility of preoperative screening colonoscopy in gynecologic oncology.

The American Cancer Society (ACS) recommends that asymptomatic women, age 50 and over, undergo sigmoidoscopy every 3 to 5 years, after two negative yearly exams. Epidemiologic evidence suggests that women with gynecologic or breast cancers have an increased risk of developing colon cancer. It is unclear whether the ACS guidelines are applicable for women with a new diagnosis of gynecologic malignancy. This retrospective study was undertaken to assess the usefulness of preoperative colonoscopy in our gynecologic oncology patient population. Patients undergoing evaluation for a major operative procedure for known or suspected gynecologic malignancies were referred for colonoscopy at the discretion of their attending surgeon. Five hundred patients' charts were reviewed to identify 212 patients in whom preoperative colonoscopy was performed (the study group). In this group, 17 cases of colonic polyps, 5 cases of synchronous colon cancer, and 2 cases of cancer metastatic to the colon were discovered, representing 11% of the study group. Whereas 23% of the patients screened were less than 50 years of age, only two cases of polyps occurred in this age group, and no cases of cancer. Patients aged 70 or greater made up 28% of the study group, but accounted for 41% of the cases of polyps and 40% of the colon cancers. Twenty-nine percent of the study group had adenocarcinoma of the endometrium, representing 7 of 17 cases of polyps, 1 of 5 colon cancers, and 1 of 2 metastatic cancers. Although this retrospective study involved colonoscopy, the locations of the observed lesions were within the theoretic reach of a flexible sigmoidoscope in 75% of cases. We conclude that in the preoperative workup of gynecologic oncology patients, no colon screening is needed in the asymptomatic patient less than 50 years of age. ACS guidelines are appropriate for patients aged 50-70, but for those 70 or greater we would consider full colonoscopy.

Age Factors↗

PubMed1989

Follow-up after polypectomy of colorectal adenomas. The importance of total colonoscopy.

Five hundred eighty-two patients with colorectal adenomas or early cancers were polypectomized from 1974 to 1985. In 100 patients, total colonoscopy was performed more than twice after the initial polypectomies. These patients were divided into three groups: group A patients underwent total colonoscopy at 1-year intervals; group B patients underwent total colonoscopy at 2-year intervals, group C patients underwent total colonoscopy at 3-year or more than 3-year intervals. The frequency and location of newly developed adenomas were investigated. The detection rate for new adenomas was 13% in group A and 50% in group B; thus, there was a significant difference between group A and group B (P less than 0.01). The transverse colon is the only segment where the topological proportion of newly developed adenomas increased in comparison with that of index adenomas (P less than 0.05). The detection rate for new adenomas was significantly higher in patients who had carcinoma in situ at the time of initial polypectomy (P less than 0.05). Questionnaires about colonoscopy and colonic adenomas were therefore mailed to the patients who were lost to follow-up after the polypectomy.

Colonic Polyps↗

PubMed1987

Prospective assessment of risk of bacteremia with colonoscopy and polypectomy.

A prospective assessment was made of the frequency of positive blood cultures in patients undergoing colonoscopy with or without polypectomy. A total of 270 patients underwent 280 colonoscopies, of these, there were 105 patients that had 111 polypectomies. Blood cultures were taken prior to and within 15 min following each procedure. Six of 280 (2.1%) preprocedural blood cultures were positive. Seven of 169 (4%) blood cultures were positive within 15 min of insertion of the colonoscope in the colonoscopy only group. Eight of 223 (3.6%) blood cultures were positive within 10 min of the polypectomy. There was no clinical evidence of sepsis during the 24 hr following these procedures. In order to determine appropriate postprocedural sampling intervals, we induced a Staphylococcus epidermidis bacteremia with a mean of 1.16 X 10(6) colony forming units/ml on 10 occasions in seven dogs. Within 30 min of inoculation, we were able to detect only one colony forming unit/ml. The rate of positive blood cultures during colonoscopy alone and following polypectomy during colonoscopy is comparable to other gastrointestinal endoscopy procedures. The most optimal time to collect blood cultures in order to detect transient bacteremia is as soon after the procedure as is feasibly possible.

Animals↗

PubMed1996

Colonoscopy without sedation.

PURPOSE AND METHODS: Two hundred fifty-eight consecutive nonsedated colonoscopies were prospectively evaluated over an 18-month period. The cecum was intubated in 250 cases (97 percent). Polypectomies or biopsies were performed in 77 cases (31 percent). Indications for colonoscopy included history of polyps (32 percent), hematochezia (28 percent), family history of colon cancer (16 percent), prior history of colon cancer (9 percent), change in bowel habits (12 percent), abnormal flexible sigmoidoscopy (6 percent), and inflammatory bowel disease (3 percent). RESULTS: Sedation was withheld for the following reasons: patient preference (57 percent), medical problems (2 percent), prior resection (16 percent), surgeon preference (6.5 percent), lack of intravenous access (3 percent), and age (1 percent). Three patients (1.5 percent) required sedation to complete the procedure. Procedure-related pain was based on a scale from zero to three. One hundred thirty-nine patients (61 percent) rated their pain as either zero (no pain) or one (mild pain), and 217 patients (8 percent) indicated that they would prefer their next colonoscopy to be performed without sedation. One hundred twelve patients had previously undergone sedated colonoscopy. Ninety-two (92 percent) preferred nonsedated to sedated procedures. Average procedure time was 13.7 (range, 0.5 to 85) minutes. CONCLUSIONS: Several series have studied nonsedated endoscopic upper and lower gastrointestinal evaluations. None, however, have evaluated patient comfort and satisfaction. In our prospective series of 258 consecutive nonsedated colonoscopies, we found the procedure to be safe, effective, and well accepted.

Colonoscopy↗

PubMed1995

Factors that predict incomplete colonoscopy.

PURPOSE AND METHODS: Certain factors in a patient's history, such as prior abdominal surgery or complicated diverticular disease, have been reported to hinder cecal intubation during colonoscopy. Over a 16-month period, 1,047 consecutive colonoscopies were prospectively evaluated to determine whether these factors were indeed clinically relevant. RESULTS: Of the 90 patients (9 percent) who had incomplete intubation of the colon, there were significantly more women (66 percent) than men (34 percent) (P < 0.001). Women with a history of abdominal hysterectomy had a significantly lower cecal intubation rate (P < 0.01). A history of diverticulitis did not alter the cecal intubation rate. In patients with incomplete colonic intubation, the most proximal extent of intubation was the sigmoid colon in women (31 percent) and the right colon in men (68 percent). Sixty-seven percent of patients with incomplete intubation of the colon had a prior colonoscopy completed to the cecum (67 percent women, 67 percent men), whereas 50 percent had a follow-up colonoscopy completed to the cecum (56 percent women, 40 percent men). CONCLUSIONS: Women, especially those with a history of abdominal hysterectomy, had a significantly lower cecal intubation rate usually because of an impassable sigmoid colon. Prior inability to complete colonoscopy to the cecum does not necessarily forecast future failure.

Abdomen↗

PubMed1992

Can Hemoccult-II replace colonoscopy in surveillance after radical surgery for colorectal cancer and after polypectomy?

Surveillance after colorectal carcinoma and adenoma includes colonoscopy, which is a demanding procedure for the patient, doctor, and society. Therefore, it was investigated whether a simple fecal occult blood test could replace colonoscopy. Hemoccult-II (H-II) was performed before 1,244 colonoscopies in patients with previous cancer and before 328 colonoscopies in an adenoma surveillance program. The H-II test was positive in 3 of 9 patients with local recurrence, in 2 of 13 with metachronous cancer, and in 31 of 186 with adenomas. The test was positive more often in patients with large and multiple adenomas, sigmoid adenomas, and adenomas with villous elements and moderate-to-severe dysplasia, but the sensitivity did not reach more than 25 to 40 percent. It was concluded that markers more sensitive than H-II are needed to detect metachronous cancers and new adenomas. In the meantime, colonoscopy has to be used with intervals of several years, but not for detection of local recurrent cancer, which in most cases may be found by simpler means.

Chi-Square Distribution↗

PubMed1994

Colonoscopy of acute colitis. A safe and reliable tool for assessment of severity.

Complications that might lead to surgery in severe attacks of ulcerative colitis have been found to be correlated with the depth of colonic ulcerations as measured by pathological examination of colectomy specimens. In order to evaluate the value of colonoscopy for the assessment of colonic ulcerations, we have reviewed the clinical, biological, colonoscopic, and anatomical findings in 85 consecutive patients with attacks of ulcerative colitis involving at least the rectosigmoid and part of the descending colon, seen in our center between 1981 and 1989. All had colonoscopy performed by a senior endoscopist at entry. Extensive deep colonic ulcerations were diagnosed in 46 of them, and moderate endoscopic colitis in 39. No complication related to colonoscopy occurred except for one colonic dilatation. Forty-three of the 46 patients with severe endoscopic colitis were operated upon; 38 of them failed to improve with high-dose corticosteroids and five had a toxic megacolon. Extensive ulcerations reaching at least the circular muscle layer were found at pathological examination of colectomy specimen in 42 of the 43 patients. Conversely, 30 of 39 patients with moderate endoscopic colitis went into clinical remission with medical treatment, and only nine patients needed further surgery because of medical treatment failure. Six of these nine patients underwent another colonoscopy prior to colectomy, and all six showed features of severe endoscopic colitis. Deep ulcerations reaching the circular muscle layer were found at pathological examination in five of these six patients and in one additional patient whose colonoscopy had been performed 21 days before colectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed2000

Predictive factors for detecting colorectal carcinomas in surveillance colonoscopy after colorectal cancer surgery.

PURPOSE: The aim of this study was to identify the high-risk groups for metachronous colorectal carcinoma among patients who undergo colorectal cancer surgery. METHODS: Three hundred forty-one patients undergoing colorectal cancer surgery who had undergone surveillance colonoscopy at least twice during a period of more than three years were analyzed. A metachronous colorectal carcinoma was defined as a new colorectal carcinoma detected by surveillance colonoscopy after surgery. RESULTS: Surveillance colonoscopy was performed 4.6 times per patient during an average of 6.2 years. Twenty-two metachronous colorectal carcinomas in 19 patients were detected, and 14 (64 percent) of 22 were detected within five years of surgery. The cumulative incidence of developing colorectal carcinomas during a five-year period was 5.3 percent. Seventeen (77 percent) of 22 carcinomas were 10 mm or less in size. Ten (71 percent) of the 14 carcinomas in early stages showed a flat appearance. Univariate analysis showed that extracolonic malignancy, coexistence of adenoma, and synchronous multiple colorectal carcinoma were significant predictive factors for detecting colorectal carcinomas in surveillance colonoscopy and that family history of colorectal carcinoma was a possible predictive factor. Multivariate analysis performed with Cox proportional hazards regression model showed that extracolonic malignancy and the coexistence of adenoma were significant predictive factors. CONCLUSION: We recommend that patients with the above predictive factors receive surveillance colonoscopy meticulously and regularly.

Adult↗

PubMed1988

Review of recurrent polyps and cancer in 500 patients with initial colonoscopy for polyps.

Five hundred patients with 1240 polyps removed by colonoscopy and polypectomy over a 13-year period are the subject of ongoing follow-up study. Ninety-three percent of the patients have been followed an average of 53 months with a recurrence rate of polypoid disease in 26 percent, of which approximately 7 percent demonstrated malignant changes. This compares to a rate of 7 percent metachronous cancer in patients with a malignancy demonstrated at any time in the past. The highest risk group for recurrence are patients with more than four polyps at initial colonoscopy, with a 59 percent recurrence rate. The following recommendations for follow-up are made: 1) Flexible sigmoidoscopy is adequate yearly follow-up if the original polyps are confined to the rectum and sigmoid. 2) Colonoscopy should be carried out the first year if the original polyps are beyond the rectum and sigmoid, and yearly until the colon is cleared of recurring lesions. 3) Colonoscopy is indicated in patients with cancer before surgery if possible; if not, within six months after resection. 4) Interval six-month examinations are indicated in patients with colon cancer and multiple synchronous polyps until the colon is cleared. 5) Large, sessile polyps resected piecemeal require a three-month follow-up until gone. 6) When the above conditions are met, colonoscopy at three-year intervals is adequate for long-term follow-up of neoplastic polyps to detect and prevent early malignancy.

Adult↗

PubMed1989

Reliability of colonoscopy.

In an effort to determine the reliability of colonoscopy the authors retrospectively reviewed preoperative colonoscopic findings and compared them with the postoperative pathologic specimen reports. Only lesions greater than 0.5 cm were included in the comparison. Over a 13-year period, 429 patients with colorectal cancer underwent preoperative colonoscopy. Four hundred thirteen (97 percent) of the colonoscopic examinations correlated with the pathologic specimen, but, in 16 cases (3 percent), lesions were missed. In total, 17 adenomatous polyps and 3 cancers were found in the surgical specimens that were not documented at colonoscopy. Eighteen patients had total preoperative colonoscopy and total abdominal colectomy, which makes for a reliable model to judge the accuracy of colonoscopy. In these 18 patients, 17 of the pathologic specimens correlated with the endoscopic findings, which yields an accuracy rate of 94 percent. Blind areas in the colon, plus misjudgment that the scope had reached the cecum, are responsible for the majority of colonoscopic errors.

Colonoscopy↗

PubMed1987

The role of colonoscopy and flexible sigmoidoscopy in screening for colorectal carcinoma.

Six hundred thirty-two patients were referred to the Colorectal Clinic from February 1983 to February 1986 for screening with the Pentax 65 cm flexible sigmoidoscope. Forty-nine of these patients (8 percent) had adenomatous polyps. There were 27 males and 22 females. The mean distance examined by the 65 cm flexible sigmoidoscope was 55 cm. Five patients were excluded from analysis, leaving 44 patients who underwent colonoscopy to the cecum. At the time of colonoscopy, 15 of the 44 patients (34 percent) had one or more adenomatous polyps beyond reach of the 65 cm flexible sigmoidoscope. The remaining 29 patients who underwent colonoscopy had no polyps beyond reach of the 65 cm flexible sigmoidoscope. Thirty adenomatous polyps, one invasive carcinoma of the ascending colon, and one hyperplastic polyp were found in these 15 patients. In summary, 34 percent of patients found to have adenomatous polyps within reach of the 65 cm flexible sigmoidoscope harbored one or more adenomatous polyps in the proximal colon at the time of colonoscopy. A positive 65 cm flexible sigmoidoscope examination requires colonoscopy to identify and remove proximal premalignant lesions, thereby aborting the polyp-cancer sequence.

Colonic Neoplasms↗

PubMed1982

Colonoscopy: its role in cancer of the colon and rectum.

In order to determine the feasibility, yield, and impact of routine total colonoscopy on the management of large-bowel cancer, 157 cancer patients underwent 175 colonoscopic procedures; 13.6 per cent of the cancers had been missed on double-contrast barium enema examination. Among 92 patients undergoing perioperative colonoscopy, the lesion was reached in 90 per cent and the cecum in 60 per cent; 7.6 per cent demonstrated synchronous cancers, all curable, and all missed on barium-enema examination. Seventy-eight patients underwent colonoscopy at an average of 3.7 years after treatment of the index cancer; 7.7 per cent demonstrated metachronous cancers, all curable, two-thirds of which were missed on barium-enema examination. Benign polyps were noted in 62 per cent of the patients studied; 77 per cent of those polyps, 1 cm or greater in size, were missed on barium-enema examination. Polyps were found proximal to the cancer in 60 per cent of the patients with polyps. Approximately 85 per cent of those with multiple cancers demonstrated benign polyps. Preoperative total colonoscopy with periodic postoperative colonoscopy at an interval of three to five years are essential in the reliable detection of synchronous cancers and for the detection of metachronous cancers at an earlier, more favorable stage.

Cecal Neoplasms↗

PubMed2004

[Preoperative colonoscopy before esophagectomy and reconstruction with gastric interposition].

INTRODUCTION: The standard treatment of esophageal carcinoma is esophagectomy and reconstruction with gastric interposition. In many centers, preoperative colonoscopy is routinely performed in order to exclude any significant colonic pathology. This is important in case of the intraoperative necessity to use a colon interposition due to gastric pathology, anatomical variation, or injury of gastric vascularization. PATIENTS AND METHODS: Two hundred twenty-eight consecutive patients with esophageal carcinoma (adenocarcinoma 102, squamous cell carcinoma 126) who underwent esophagectomy were included in this study. Of them, 171 (75%) had preoperative colonoscopy. Reconstruction was done by gastric tube in 219 and colon interposition in nine. RESULTS: Intraoperative conversion to colon interposition was necessary in none of the 219 patients with intended reconstruction by a gastric conduit. In two of 171 patients (1.2%), preoperative colonoscopy revealed pT1 adenocarcinomas of the colon which were completely removed by endoscopy, and a total of 62 adenomas were histopathologically diagnosed. Fifty-three patients (31%) had endoscopic evidence of asymptomatic diverticulosis. No complications were observed after colonoscopy. CONCLUSION: Preoperative colonoscopy prior to esophagectomy and intended gastric tube formation appears unnecessary from the surgical point of view, as intraoperative conversion to a colon interposition is rare. The rate of colon adenomas or carcinomas was not increased in patients with adeno- or squamous cell carcinoma of the esophagus than in an age-matched, normal population.

Adenocarcinoma↗