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PubMed1997

CT colonoscopy of colorectal neoplasms: two-dimensional and three-dimensional virtual-reality techniques with colonoscopic correlation.

OBJECTIVE: The aim of this study was to compare the diagnostic accuracy of two-dimensional (2D) CT colonography and three-dimensional (3D) virtual colonoscopy with conventional colonoscopy in patients who have suspected colorectal neoplasms. SUBJECTS AND METHODS: Twenty patients were studied (eight women and 12 men; mean age, 53 years; range, 42-85 years). All patients had findings on conventional colonoscopy suggestive of colorectal carcinoma and underwent colonic CT within 3 hr of endoscopy. Two-dimensional CT colonography and 3D virtual colonoscopy images were generated from the same data set that was obtained from thin-section helical CT of the abdomen and pelvis after rectal insufflation of room air. Three-dimensional virtual colonoscopy images were obtained by downloading CT data to a workstation equipped with commercially available software. Volume- and perspective-rendering techniques were used to achieve interactive, 3D virtual "fly-through" examinations of the colonic mucosa. The results of 2D CT colonography and 3D virtual colonoscopy were compared with the findings of conventional colonoscopy and correlated with surgical and pathologic outcome where possible. RESULTS: Twenty masses (defined as intraluminal projections 2 cm or larger in diameter) and 15 polyps (defined as projections smaller than 2 cm in diameter) were identified in our study group. All masses and 14 of 15 polyps were successfully shown on 2D colonography. Three findings of polyps on 2D colonography were false-positive, and one was false-negative. Three-dimensional virtual colonoscopy revealed 19 of 20 masses and 13 of 15 polyps. On conventional colonoscopy, all 20 masses and 13 of 15 polyps were identified, with one false-positive finding of a malignant stricture in a normal colon. Complete examination of the colon was possible in 18 of 20 patients using the 2D technique and in 17 of 20 patients using 3D virtual colonoscopy, whereas conventional colonoscopy showed the entire colon in only 12 of 20 patients. CONCLUSION: Two-dimensional CT colonography and 3D virtual colonoscopy are complementary and effective techniques for examining the colon in patients with suspected colorectal carcinoma. CT techniques offer several advantages over conventional colonoscopy including the ability to detect abnormalities proximal to obstructing carcinomas, accurate localization of abnormalities within the colon, and good patient tolerance. These CT techniques may play an important role in future diagnosis of colorectal cancer and for screening patients at risk.

Colonic Polyps↗
PubMed2004

The effect of diagnostic confidence on the probability of optical colonoscopic confirmation of potential polyps detected on CT colonography: prospective assessment in 1,339 asymptomatic adults.

OBJECTIVE: We sought to evaluate the effect of interpreter confidence on the likelihood that a lesion detected on CT colonography (CTC) will correspond to a matched polyp seen on optical colonoscopy. SUBJECTS AND METHODS: Same-day CTC and optical colonoscopy were performed on 1,339 asymptomatic adults. A standard matching algorithm for polyp size and location was used. For each potential polyp detected on CTC, the level of diagnostic confidence was prospectively rated on a 3-point scale (1, least certain; 2, intermediate; and 3, most certain). RESULTS: For CTC-detected lesions 6 mm or larger, diagnostic confidence levels of 1, 2, and 3 corresponded to matched polyps on optical colonoscopy in 33.3% (45/135), 50.0% (103/206), and 66.8% (157/235) of cases, respectively (p < 0.01). Similar trends were present for categories of lesions that measured 6-7 mm, 8-9 mm, and 10 mm or larger, rising to a match rate of 82.1% (55/67) for lesions 10 mm or larger that were diagnosed with a level-3 confidence rating. The likelihood that a matched polyp was adenomatous increased with greater levels of diagnostic confidence. Of note, level-3 confidence for lesions measuring 8-9 mm on CTC more often yielded a matching neoplasm on optical colonoscopy than level-1 or level-2 confidence for lesions measuring 10 mm or larger (60.3% [35/58] vs 20.8% [10/48]; p < 0.0001). CONCLUSION: Greater diagnostic confidence for an individual lesion detected on CTC correlates with a significantly increased likelihood that a matching polyp will be found on optical colonoscopy and that this matched polyp will be neoplastic. Although polyp size represents the primary criterion for CTC screening algorithms, this data could help guide the decision to opt for noninvasive CTC surveillance versus optical colonoscopy for polypectomy.

Aged↗
PubMed1985

Reproducibility and diagnostic value of Hemoccult-II test. A colonoscopic evaluation in asymptomatic patients.

Inter-observer agreement rate in double readings of 246 Hemoccult-II tests was 0.88 (Kappa analysis). The slides were not rehydrated. The Hemoccult-II test was performed immediately before 748 total colonoscopies in asymptomatic patients after previous polypectomy or radical surgery for cancer to estimate the diagnostic value of the test in mass screening, accepting a higher prevalence of neoplasia in the study group but realizing that colonoscopy can only be performed in high-risk groups. Another purpose was to investigate the possibility of replacing colonoscopy with Hemoccult-II in surveillance after previous adenoma or cancer. The 79 colonoscopies after a positive test showed cancer in 3, adenomas in 13, and other intestinal pathology in 34 cases. The 669 colonoscopies after negative tests showed cancer in 1, adenomas in 67, and other pathology in 141 cases. In conclusion, the test cannot be used as a guideline for colonoscopy in follow-up programs for patients who have had adenomas, since it missed 84% of the new cases in the present series. The test does not exclude the presence of colorectal carcinoma, but the risk of cancer is probably several times less in patients with negative tests (1 of 669) than in patients with positive tests (3 of 79), which may justify the use of the Hemoccult-II test for mass screening in asymptomatic populations.

Adenoma↗
PubMed1992

Colonoscopic screening examination of relatives of patients with colorectal cancer. II. Relations between tumour characteristics and the presence of polyps.

Colonoscopy was offered to 206 first-degree relatives of 181 patients operated on for colorectal cancer (CRC). Findings of polyps in relatives correlated with Dukes staging, extent of dedifferentiation and localization of tumour in the operated patient, and type of family relationship. Adenomas in relatives and Dukes staging of carcinoma in the patients were inversely related. Relatives of patients with Dukes stage A tumour had more than twice as many adenomas as and a higher prevalence of multiple adenomas than relatives of patients with advanced cancer at the time of operation. If the patient had polyp(s) in addition to tumour, the number of adenomas per relative was almost doubled. Hyperplastic polyps in relatives were associated with poorly differentiated carcinoma in their related patients. These results support the theory that not all CRC are derived from polyps and that adenoma-derived CRC may have a better prognosis than 'de novo' CRC. An adenoma prevalence risk table is also presented.

Adenoma↗
PubMed2006

Colonoscopic evaluation of hematochezia in low and average risk patients for colorectal cancer: a prospective study.

AIM: To relate the endoscopic findings in patients with hematochezia with regard to age in "low and average risk" for colorectal cancer (CRC) and to localize significant lesions in order to identify patients who need sigmoidoscopy or total colonoscopy. METHODS: This prospective study was performed in an open access GI endoscopy unit. Out of 4322 consecutive patients undergoing colonoscopy, 918 reported hematochezia. The final study group comprized 180 patients aged below 45 and 237 over 45. Main exclusion criteria were a 1st-degree family history of colorectal carcinoma, patients reporting blood mixed with stools and/or progressive colonic symptoms, or patients who had undergone colon surgery for neoplastic lesions. RESULTS: Total colonoscopy could be performed in 96% of patients. Abnormal findings were observed in 34.3% of the younger and in 65.7% of the older ones. Findings were the presence of polyps in the distal colon (n = 2) and IBD in the proximal colon (n = 29) in the group of the younger patients, and polyps (n = 15), IBD (n = 13), and carcinoma (n = 6, 4 of the lesions were located proximal to the splenic flexure) in the elderly. Our findings suggest that the diagnostic potential of total colonoscopy in patients younger than 45 referring scant hematochezia, is not mandatory. By exploring only the distal tract of the colon we have misdiagnosed two cases of IBD located in the ascending colon. In this group of patients additional risk factors must be identified before performing a total colonoscopy. Regarding the patients older than 45 yr, the exploration of the distal colon would have led to our overlooking a carcinoma, two neoplastic polyps and one IBD located in the proximal colon. CONCLUSION: Young patients with scant hematochezia but without risk factors for neoplasia do not need a total colonoscopy, whereas is mandatory performing a total colonoscopy in older patients even in the presence of anal pathology.

Adolescent↗
PubMed2005

Colonoscopic findings of symptomatic patients aged 50 to 80 years suggest that work-up of tumour suspicious symptoms hardly reduces cancer-induced mortality.

QUESTIONS UNDER STUDY: The risk of colorectal cancer (CRC) starts to increase at the age of 50 years in average persons without special risk factors. The significance of clinical symptoms and frequency of endoscopies done at this age are hitherto unknown. We do not know the stage of colorectal cancers nor the distribution of advanced neoplasms in symptomatic persons above 50 years. These data are of interest to validate the necessity of screening programmes, to define the target population and to interpret results of screening studies in asymptomatic people. METHODS: Endoscopies of the colon performed from 1991 to 2000 in symptomatic patients aged 50 to 80 in the well-defined area of Uri were analysed retrospectively, focusing on symptoms leading to the endoscopy and the occurrence of neoplastic lesions. RESULTS: Sixteen percent of the population at the age of 50-80 years had a colonoscopy for workup of symptoms. A CRC was found in 5.5% of all patients (83 of 1514 patients), in 12.3% of patients with tumour suspicious symptoms, but only in 0.3% of patients with unspecific pain. Stage of tumours was often advanced (82% T3/T4, 38% N1-3, 21% M1). In 2.6% of patients a colorectal cancer was found before the age of 60, mostly in men. Advanced lesions were more frequent in men, increasing with age. CONCLUSIONS: A substantial part of the population above the age of 50 had an endoscopic workup of the colon for symptoms, what has to be considered when defining the target population and the necessary manpower of screening programmes. Tumour-suspicious symptoms were significant predictors for the presence of a CRC, but tumours were often already advanced. This underlines the importance to screen persons before developing symptoms.

Adenoma↗
PubMedDate not supplied

[A comparative study of 2 methods of preparation for colonoscopic procedure].

BACKGROUND: Although ingestion of polyethylene glycol solution has become the standard preparation for colonoscopy since 1980, there is investigation of new safe, comfortable and cheap methods. OBJECTIVE: We carried out a prospective study in order to compare the utility and tolerance related to the preparation of the colon for colonoscopy, using a dioctyl sodium sulfosuccinate enema (SD) versus our conventional preparation. METHOD: Group A was prepared the day previous to the study with liquid diet, oral laxative and application of an SD, prior to the endoscopy received another SD. Group B was prepared three days with liquid diet, the day previous to the colonoscopy they ingested oral laxative and used a water enema (W(e)), and they used another W(e) the day of the procedure. The patients' tolerance in each case was compared using a scale assigned as good, fair and poor. The cleaning obtained in the colon was also evaluated in a scale of good, regular and bad, considering three colon segments. RESULTS: Forty-four patients had been studied, 19 men and 25 women; each group with 22 patients. In group A: the preparation tolerance was good in 14 cases (63.6%), fair in seven (31.8%) and poor in one (4.5%); also, the obtained cleaning up to the cecum was good in nine cases (40.9%) and fair in 13 (59%). In group B: the tolerance was good in five cases (22.7%) fair in 12 (54.5%) and poor in five (22.7%); the obtained cleaning in this group up to the cecum was good in two cases (9%), fair in 19 (86.3%) and poor in one (4.5%). CONCLUSIONS: The SD preparation was better tolerated and more effective in order to achieve the cleaning of the colon than the conventional one.

Adult↗
PubMedDate not supplied

Colonoscopic evaluation of immunochemical fecal occult blood test for detection of colorectal neoplasia.

BACKGROUND/AIMS: This study was carried out to assess the validity of three testing methods of immunochemical occult blood according to the number of collection times as a means for colorectal cancer screening. METHODOLOGY: Four thousand six hundred and eleven asymptomatic individuals, who received both an immunochemical occult blood test with a three-day method and colonoscopy during a medical checkup, served as subjects for this study. For evaluation of the desirable number of sampling times, we used the results of the first day for the 1-day method, the results of the first and second days for the 2-day method, and the results of three-consecutive days for the 3-day method. Sensitivities and specificities of these three testing methods were evaluated. RESULTS: Sensitivities and specificities for colorectal cancer were calculated to be 56% and 97% for the 1-day method, 83% and 96% for the 2-day method, and 89% and 94% for the 3-day method, respectively, showing a significant difference in sensitivity between the 1-day and the 2-day methods, as well as the 3-day method (p < 0.01), and in specificity between the 1-day as well as the 2-day and 3-day methods (p < 0.05). CONCLUSIONS: These findings indicate that the immunochemical fecal occult blood test is useful for the diagnosis of colorectal cancer, and that 2-day testing is recommended as a means of screening for colorectal cancer.

Adenoma↗