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.     

The genomic organization of the genes for human lipopolysaccharide binding protein (LBP) and bactericidal permeability increasing protein (BPI) is highly conserved

PURPOSE: The authors evaluated computed tomographic (CT) virtual colography for the detection of simulated polyps under ideal conditions, as well as the effects on lesion conspicuity of (a) collimation, (b) table pitch, and (c) orientation of the colon lumen with respect to the gantry. MATERIALS AND METHODS: Pig colon was resected and cleansed, and polyps with diameters of 3, 7, and 10 mm were created. Each specimen was scanned with collimation of 5 and 7 mm and table pitch of 1.0, 1.6, and 2.0 at angles of 0 degrees, 45 degrees, and 90 degrees to the gantry. The initial two-dimensional (2D) images were reconstructed at 1-mm intervals (2D reconstructions), from which three-dimensional (3D) virtual colography images were generated. Polyp conspicuity on the initial and reconstructed 2D images and the 3D reconstructions was evaluated on a three-point scale: 0 = polyp not depicted, 1 = polyp faintly depicted, and 2 = polyp clearly depicted. RESULTS: The 10-mm-diameter polyp was clearly depicted (grade 2 conspicuity) on every initial and reconstructed 2D image and 3D reconstruction without regard to collimation, table pitch, or angle to the gantry. The 7-mm-diameter polyp was clearly depicted (grade 2 conspicuity) on every initial and reconstructed 2D image, but conspicuity on 3D reconstructions varied as the imaging parameters varied. The 3-mm-diameter polyp was faintly depicted (grade 1 conspicuity) on the initial and reconstructed 2D images and 3D reconstructions, but conspicuity varied on the 3D reconstructions as the imaging parameters varied. CONCLUSION: CT virtual colography helped detection of small mucosal polyps regardless of the angle of the colon lumen to the gantry at which they were obtained.     

Community screening for colorectal cancer in north-eastern New South Wales, 1987-1996

OBJECTIVE: To analyse results of Bowelscan, a community-based colorectal cancer screening program using Hemoccult II, and targeting people aged 40 years and over. DESIGN: Survey of data from medical practitioners on follow-up of positive tests. SETTING: North-eastern New South Wales (Rotary District 9650), 1987-1996. SUBJECTS: 3845 people with positive results for faecal occult blood. OUTCOME MEASURES: Investigations performed; final diagnoses; number, site and Dukes' stage of colorectal carcinomas; number and histological diagnosis of colorectal polyps. RESULTS: 239,500 Hemoccult II kits were distributed between 1987 and 1996, with an estimated return rate of 80%-85%. Positive results for faecal occult blood were reported for 3845 tests (1.6% of those distributed), with 78% of these investigated by colonoscopy and/or barium enema. Investigation resulted in diagnosis of 260 colorectal carcinomas in 252 people (6.7%); 74 of these (29%) were in the caecum or ascending or transverse colon. Dukes' tumour stages were: A, 107 (41%); B, 86 (33%); C, 49 (19%); D, 16 (6%); and unknown, 2 (0.8%). (Corresponding figures from the NSW Central Cancer Registry were: A and B, 48%; C, 26%; D, 14% and unknown 12%) [corrected]. Colorectal polyps were found in a further 819 people (21.3%), and were adenomatous in 577 (79% of the 733 in whom histological diagnosis was available). Other gastrointestinal conditions were found in 1343 people (34.9%), while no cause was found for the positive result, despite adequate investigation, in 873 (22.7%). CONCLUSION: Community-based screening with faecal occult blood testing detected colorectal carcinomas at earlier histological stages than colorectal carcinomas reported to the Cancer Registry and should reduce mortality from this disease. Treatment and follow-up of adenomatous polyps detected by such a program might minimise the incidence of colorectal carcinoma in this group.     

基于多目标支持向量机的ADHD分类

针对结直肠息肉图像分割中病灶区域尺度变化大、边缘模糊以及息肉与正常组织对比度低等问题,导致病变区域分割精度低和分割边界存在伪影,提出一种基于Swin Transformer和图形推理的自适应网络. 该网络一是利用Swin Transformer编码器逐层提取输入图像的全局上下文信息,弱化背景信息干扰,多尺度分析病变区域的显著性特点. 二是提出全局与局部特征交互模块增强网络对复杂病灶的空间感知能力,突出待分割目标的关键位置信息,精准定位目标. 三是通过区域引导图推理模块以图循环递推的方式挖掘先验信息之间的高阶显性关系,促进图间信息传递. 四是设计面向边缘细节的边缘约束图推理模块,整合边缘细节,改善分割效果,提高分割精度. 在CVC-ClinicDB、Kvasir、CVC-ColonDB和ETIS数据集上进行实验,其Dice系数分别为0.939,0.926,0.810和0.788,平均交并比分别为0.889,0.879,0.731和0.710,分割性能优于现有方法. 仿真实验结果表明,对于形态结构复杂、对比度低和边缘模糊的结直肠息肉图像均有较高的分割精度.

     

Virtual colonoscopy with magnetic resonance imaging: in vitro evaluation of a new concept

BACKGROUND & AIMS: Screening for colonic polyps is desirable. A new concept based on cross-sectional and endoscopic analysis of a magnetic resonance (MR) data set is presented. METHODS: Ex vivo autopsy colonic specimens, containing artificially placed polyps, were obtained and filled with a gadolinium-containing solution. Forty-four thin-section MR images were obtained in a 1.5-T MR scanner in 28 seconds. A three-dimensional endoscopic fly-through of these images was rendered. Fly-throughs and two-dimensional cross-sectional images were analyzed by two observers for the presence of polyps. RESULTS: The average sensitivity and specificity for the detection of polyps based on three-dimensional endoscopic MR colon imaging were 87% and 96%, respectively. Analysis of cross-sectional images showed an overall sensitivity and specificity of merely 57% and 84%, respectively. The difference in the interpretation of three-dimensional MR colonoscopy and two-dimensional cross-sections was statistically significant (P < 0.001). With three-dimensional MR colonoscopy, overall sensitivity for detection of polyps measuring < or =5 mm in length and diameter was 70%; for larger polyps, it increased to 95% (P < 0.01). CONCLUSIONS: The feasibility of an MR-based endoluminal assessment of the colon is shown. Minimal invasiveness, lack of radiation exposure, and high in vitro diagnostic accuracy warrant further investigation of this novel concept.     

Phantom study of optimization of spiral-CT and 3D reconstruction of the tracheobronchial system

PURPOSE: To optimise three-dimensional spiral CT of the tracheobronchial tree using adequate acquisition and reconstruction parameters for spiral CT of the chest. MATERIAL AND METHODS: Qualitative and quantitative assessment of different 3 D reconstructions of two test objects of the tracheobronchial tree depending on section thickness, reconstruction interval, pitch, and reconstruction algorithm used in spiral CT (Siemens, Somatom plus S) of the chest. The frequency of volume and stairstep artifacts was evaluated. The 3 D reconstructions were generated using a seeded VOI-technique (Allegro, ISG). RESULTS: Reduction of artifacts was achieved by decreasing section thickness. Increasing overlap of source images, lowering the pitch factor, and application of the reconstruction algorithm "slim". Section thickness was the single most important factor which was mainly responsible for the occurrence of volume artifacts. Stairstep artifacts were primarily influenced by the reconstruction interval. CONCLUSION: Spiral CT with a section thickness > 4 mm is not adequate for 3 D reconstructions of the tracheobronchial tree. Overlapping source images with a pitch of 1 and the reconstruction algorithm "slim" can be recommended to reduce artifacts.     

Colorectal adenoma in patients with a history of breast cancer: a prospective study in Taiwan

The increased incidence of colorectal cancer in women with a history of breast cancer is well established. However, the relationship between the prevalence of adenomatous polyps and breast cancer is still controversial. We conducted a prospective study of the incidence of colorectal polyps in patients with a history of breast cancer in Taiwan. Eighty-nine patients (86 women and 3 men) received colonoscopy to test for precancerous lesions. Mean age was 49.4 +/- 10.4 years. Twelve polyps (9 adenomatous, 2 hyperplastic, 1 inflammatory) (13.5%) and one cancer (1.1%) were found. The mean age of patients with and without colorectal neoplasia was 56.3 +/- 9.4 and 48.2 +/- 10.2 years respectively, (p < 0.005); 10 out of 13 patients (77%) with colorectal neoplasia were over 50 (p < 0.1). Compared with a study of Chinese people in Hong Kong, our population had a lower incidence of colorectal adenomatous polyps, but breast cancer patients have a greater risk of developing colorectal cancer than the general population in Taiwan.     

Confirmation that Thiobacillus halophilus and Thiobacillus hydrothermalis are distinct species within the gamma-subclass of the Proteobacteria

BACKGROUND: There is controversy regarding the most appropriate investigation for suspected colorectal carcinoma. We offered these patients same-day flexible sigmoidoscopy (FS) and double-contrast barium enema (DCBE). METHODS: We reviewed the results of 117 consecutive adult patients. All patients underwent FS followed by DCBE on the same day. The radiographs were reviewed by two of the authors who were blinded to the clinical information, flexible sigmoidoscopy reports, and the original DCBE report. RESULTS: One hundred seventeen patients made up the study population. Thirty-four of the 117 patients had polyps and/or carcinoma. Three malignant tumours were detected by DCBE; one of these was also seen on FS, and the other two cancers were out of FS range. Fifty-three polyps were found by FS; nine were removed by biopsy prior to the enema examination. Of the 44 remaining polyps, DCBE failed to detect 87% of the 0-9-mm group and 67% of the >9-mm group. Ten polyps were seen only on DCBE; seven of these 10 were beyond the range of the sigmoidoscope, and the three remaining polyps were less than 5 mm. CONCLUSION: DCBE is insensitive in the detection of rectosigmoid polyps. FS should continue to be used as a complementary examination to DCBE in the investigation of suspected colorectal carcinoma.     

Absorbed dose and image quality in examinations of the colon with digital and analogue techniques

PURPOSE: Image quality and the absorbed dose to the patient are issues of primary interest in the change-over from the conventional analogue technique to the digital technique in the examination of the colon by means of fluoroscopy. The aim of this study was to compare the incident radiation and to evaluate the image quality in two different X-ray equipment types, one digital and one analogue. MATERIAL AND METHODS: A kerma-area product meter was used to measure the incident radiation to the patient. Both fluoroscopy and total-examination times were measured as was the number of images. An evaluation of image quality was made and statistically analysed. RESULTS AND CONCLUSION: No significant difference in the irradiation dose was observed between the two techniques. The fluoroscopy time was significantly lower with the conventional technique but the total-examination time decreased by 18% with the digital technique. The total number of images taken was higher with the digital technique (25 images compared to 19) owing to the limited field of the image intensifier. Significantly more noise and less sharpness were observed with the digital system but there was no significant difference in contrast or image quality in the various anatomical structures. Although the change-over to the digital system produced a reduction in sharpness and an increase in noise, and no significant dose saving was measured, the digital system was faster to work with and could well be used for diagnostic purposes.     

Optimization and diagnostic accuracy of computerized tomography with tridimensional spiral technique in the study of craniostenosis

INTRODUCTION: Conventional Computed Tomography (CT) with three-dimensional (3D) reconstructions is considered the most complete and accurate imaging modality to diagnose craniosynostosis. However, the introduction of Spiral CT (SCT) opened new possibilities for 3D studies of the skull in pediatric patients with craniosynostosis. The purpose of our study is two fold: first, to optimize the scanning and imaging parameters to obtain diagnostic images in a single spiral scan; second, to assess the diagnostic accuracy of such images in the identification of normal and abnormal cranial vault sutures. MATERIAL AND METHODS: Seventy-eight pediatric patients (age range: 1-35 months; mean: 11.8 months) with craniosynostosis were submitted to SCT of the head. The images were acquired with the following parameters: 3- and 5-mm nominal slice thickness, 5-6 mm/s table feed (pitch 1-2), 165 mAs and 120 kV. Two different algorithms and increases were used for image reconstructions. A first set of images was reconstructed with 2-mm increases and a soft tissue algorithm: these images were used for brain studies and for 3D reconstructions. A second set of slices was reconstructed with 5-mm increases and a bone algorithm to visualize the sutures of the axial plane. The 3D images were processed with the Shaded Surface Display software with threshold values ranging 120-150 HU. All images were acquired with a single spiral scan lasting less than 30 seconds. Two blinded radiologists analyzed the 3D and the planar images independently to evaluate the course and depth of each cranial suture. The sensitivity, specificity and diagnostic accuracy of both 3D and planar SCT images were evaluated. The frequency of artifacts (the Lego effect, boiled egg, pseudoforamina, movement, and chainsaw artifacts) and their influence on the final diagnosis were studied on 3D SCT images. RESULTS: The diagnostic accuracy rates of 3D SCT images, by suture, were: sagittal 90.7%, metopic 100%, left lamboid 90.9%, right lamboid 93.9%, left coronal 85.7%, right coronal 91.1%. The diagnostic accuracy rates of the axial images, by suture, were: sagittal 90.7%, metopic 95.5%, left lamboid 86.4%, right lamboid 90.9%, left coronal 83.7%, right coronal 91.1%. The interobserver agreement on 3D images was: sagittal 91.1%, metopic 100%, left lamboid 88.9%, right lamboid 91.1%, left coronal 88.9%, right coronal 84.4%. The Lego effect artifact was the most frequent one (82%) and affected image evaluation in 6.3% of cases. CONCLUSIONS: Our results prove that 3D SCT is a very accurate technique for identifying normal and abnormal sutures and presents many advantages over conventional 3D CT in the examination of pediatric patients with craniosynostosis. The quality of 3D SCT images was adequate and the artifacts did not affect the final diagnostic yield significantly.     

Comparison of projection algorithms used for the construction of maximum intensity projection images

OBJECTIVE: Four methods of producing maximum intensity projection (MIP) images were studied and compared. MATERIALS AND METHODS: Three of the projection methods differ in the interpolation kernel used for ray tracing. The interpolation kernels include nearest neighbor interpolation, linear interpolation, and cubic convolution interpolation. The fourth projection method is a voxel projection method that is not explicitly a ray-tracing technique. The four algorithms' performance was evaluated using a computer-generated model of a vessel and using real MR angiography data. The evaluation centered around how well an algorithm transferred an object's width to the projection plane. RESULTS: The voxel projection algorithm does not suffer from artifacts associated with the nearest neighbor algorithm. Also, a speed-up in the calculation of the projection is seen with the voxel projection method. Linear interpolation dramatically improves the transfer of width information from the 3D MRA data set over both nearest neighbor and voxel projection methods. Even though the cubic convolution interpolation kernel is theoretically superior to the linear kernel, it did not project widths more accurately than linear interpolation. A possible advantage to the nearest neighbor interpolation is that the size of small vessels tends to be exaggerated in the projection plane, thereby increasing their visibility. CONCLUSION: The results confirm that the way in which an MIP image is constructed has a dramatic effect on information contained in the projection. The construction method must be chosen with the knowledge that the clinical information in the 2D projections in general will be different from that contained in the original 3D data volume.     

Treatment of acute respiratory tract diseases in cattle with Bisolvon in combination with either enrofloxacin, cefquinome, ceftiofur or florfenicol]

The purpose of this study was to compute and compare the group mean HMPAO brain SPECT images of patients with senile dementia of Alzheimer's type (SDAT) and age matched control subjects after transformation of the individual images to a standard size and shape. METHODS: Ten patients with Alzheimer's disease (age 71.6 +/- 5.0 yr) and ten age matched normal subjects (age 71.0 +/- 6.1 yr) participated in this study. Tc-99m HMPAO brain SPECT and X-ray CT scans were acquired for each subject. SPECT images were normalized to an average activity of 100 counts/pixel. Individual brain images were transformed to a standard size and shape with the help of Automated Image Registration (AIR). Realigned brain SPECT images of both groups were used to generate mean and standard deviation images by arithmetic operations on voxel based numerical values. Mean images of both groups were compared by applying the unpaired t-test on a voxel by voxel basis to generate three dimensional T-maps. X-ray CT images of individual subjects were evaluated by means of a computer program for brain atrophy. RESULTS: A significant decrease in relative radioisotope (RI) uptake was present in the bilateral superior and inferior parietal lobules (p < 0.05), bilateral inferior temporal gyri, and the bilateral superior and middle frontal gyri (p < 0.001). The mean brain atrophy indices for patients and normal subjects were 0.853 +/- 0.042 and 0.933 +/- 0.017 respectively, the difference being statistically significant (p < 0.001). CONCLUSION: The use of a brain image standardization procedure increases the accuracy of voxel based group comparisons. Thus, intersubject averaging enhances the capacity for detection of abnormalities in functional brain images by minimizing the influence of individual variation.     

High-resolution 3D Bayesian image reconstruction using the microPET small-animal scanner

A Bayesian method is described for reconstruction of high-resolution 3D images from the microPET small-animal scanner. Resolution recovery is achieved by explicitly modelling the depth dependent geometric sensitivity for each voxel in combination with an accurate detector response model that includes factors due to photon pair non-collinearity and inter-crystal scatter and penetration. To reduce storage and computational costs we use a factored matrix in which the detector response is modelled using a sinogram blurring kernel. Maximum a posteriori (MAP) images are reconstructed using this model in combination with a Poisson likelihood function and a Gibbs prior on the image. Reconstructions obtained from point source data using the accurate system model demonstrate a potential for near-isotropic FWHM resolution of approximately 1.2 mm at the center of the field of view compared with approximately 2 mm when using an analytic 3D reprojection (3DRP) method with a ramp filter. These results also show the ability of the accurate system model to compensate for resolution loss due to crystal penetration producing nearly constant radial FWHM resolution of 1 mm out to a 4 mm radius. Studies with a point source in a uniform cylinder indicate that as the resolution of the image is reduced to control noise propagation the resolution obtained using the accurate system model is superior to that obtained using 3DRP at matched background noise levels. Additional studies using pie phantoms with hot and cold cylinders of diameter 1-2.5 mm and 18FDG animal studies appear to confirm this observation.     

AIDS complicated with disseminated toxoplasmosis: a pathological study of 9 autopsy cases

BACKGROUND: In addition to identifying and eradicating premalignant lesions, and detecting early cancer before the development of life-threatening consequences, new concepts and technological advances have stimulated a hightened interest in the secondary prevention of colorectal cancer. METHODS: People whose first degree relatives have had colorectal cancer are considered to run a higher risk of developing colorectal carcinoma. A screening program was carried out for 358 first degree relatives of colorectal cancer patients using colonoscopic screening. RESULTS: The mean age of these first degree relatives was 44 years, ranging from 13 to 78 years. Two hundred and eleven (58.9%) of them were asymptomatic. Totally 73 polyps were detected in 53 subjects (14.9%). Two cancer lesions were identified. Thirty polyps (41.1%) measured between 0.5 cm and 2.0 cm. The polyps were mostly located in the rectum and sigmoid colon (63%). One polyp was found in a subject below 30 years of age. Over the age of 30, the incidence of polyp increased dramatically. CONCLUSIONS: Our results confirmed that the screening program for the first degree relatives of patients with colorectal cancer is worthwhile. The program would have a more significant impact if the screening could start from subjects around the age of 30.     

An evaluation of the potential and limitations of three-dimensional reconstructions from intravascular ultrasound images

Three-dimensional (3D) reconstructions of arteries can be produced using two-dimensional (2D) intravascular ultrasound (IVUS) images. Any artefact that affects 2D images has the potential to limit the quality of a 3D reconstruction. Using a catheter withdrawal technique, a range of test rigs were used to assess: (i) the effect of rotation of the probe orientation; (ii) the ability to reconstruct the true path of a tortuous vessel; (iii) the effect of image distortion on diameter measurements; (iv) the number of images per unit length used to produce a 3D reconstruction; and (v) the quality of the IVUS 3D reconstruction of a stent. These investigations show that 3D IVUS imaging is prone to artefacts. For 3D IVUS images to be used to quantify the vessel path or to make accurate measurements of vessel dimensions, more information about the catheter tip position and orientation is required than is currently available with the pullback technique.     

Biochemical changes in cerebrospinal fluid associated with the neurotoxic action of HIV-1]

Different intravascular ultrasound (IVUS) systems vary in their image presentation. The purpose of this study was to compare four IVUS systems in vitro to determine the accuracy of tissue characterization of atherosclerotic plaque compared with histology. Ninety-eight plaque segments from 23 formalin-fixed human iliac arteries were imaged in saline at room temperature with four different IVUS systems. To assess the accuracy of IVUS in describing plaque, three types of analysis were performed: (1) the ability to identify the presence and extent of lumen or plaque boundary; (2) sensitivity, specificity, and interobserver variability of IVUS in qualitatively identifying plaque components compared with histology; and (3) quantification of calcification. The synthetic aperture device had a lower sensitivity in identifying lumen and plaque boundaries (87%, 38% respectively) compared with other machines (96%-100%, 95%-100%). All three mechanically rotating systems had fair to good sensitivities for identifying calcification (57%-73%) or lipid filled areas (50%-83%). The sensitivity of discriminating fibrous tissue from fatty areas was low (39%-52%). The synthetic aperture system had a significantly lower sensitivity for identifying all three tissue types (4%-21%). There was significant interobserver variability (kappa value = 0.47-0.68) as well as machine to machine variability (kappa value = 0.52) for tissue characterization. Calcified areas were underestimated by System 1 (p < .05) and System 4 (p < .01) because of weaker echo reflections or poor image quality. There are significant differences in image representation among these four IVUS systems in the diagnosis of tissue components of complex atherosclerotic plaque. These variabilities should be considered when interpreting studies performed with different machines.     

Inherited colorectal polyposis and cancer risk of the APC I1307K polymorphism

Germ-line and somatic truncating mutations of the APC gene are thought to initiate colorectal tumor formation in familial adenomatous polyposis syndrome and sporadic colorectal carcinogenesis, respectively. Recently, an isoleucine-->lysine polymorphism at codon 1307 (I1307K) of the APC gene has been identified in 6%-7% of the Ashkenazi Jewish population. To assess the risk of this common APC allelic variant in colorectal carcinogenesis, we have analyzed a large cohort of unselected Ashkenazi Jewish subjects with adenomatous polyps and.or colorectal cancer, for the APC I1307K polymorphism. The APC I1307K allele was identified in 48 (10.1%) of 476 patients. Compared with the frequency in two separate population control groups, the APC I1307K allele is associated with an estimated relative risk of 1.5-1.7 for colorectal neoplasia (both P=.01). Furthermore, compared with noncarriers, APC I1307K carriers had increased numbers of adenomas and colorectal cancers per patient (P=.03), as well as a younger age at diagnosis. We conclude that the APC I1307K variant leads to increased adenoma formation and directly contributes to 3%-4% of all Ashkenazi Jewish colorectal cancer. The estimated relative risk for carriers may justify specific clinical screening for the 360,000 Americans expected to harbor this allele, and genetic testing in the setting of long-term-outcome studies may impact significantly on colorectal cancer prevention in this population.     

Calcium chemoprevention in colorectal cancer

BACKGROUND/AIMS: There are genetic, endoengenous, and exogenous factors responsible for colorectal cancer. Calcium may play a chemopreventive role in high risk groups. Binding fatty and biliary acids and their reduced absorbtion, with a consequent decrease of proliferative stimulation and reduction of secondary carcinogenic compounds, may explain this role. MATERIAL AND METHODS: 175 patients with adenomatous polyps after polypectomy and with calcium chemoprevention were evaluated for polyps recurrence. Another three groups of patients with colorectal cancer without chemoprevention (A,B) and with chemoprevention (group C) were followed concerning survival after surgery. RESULTS: The cumulative survival rate of patients after surgery due to colorectal carcinoma is significantly higher in a calcium chemopreventive group. Adenomatous polyps recurrences after polypectomy are lower (12.9%) in the chemoprevention group than in the group without prevention (55%) with a mean time of follow-up 3.1 yrs. CONCLUSIONS: Calcium is an important chemopreventive agent in adenomatous polyps after polypectomy and after colorectal surgery for colorectal cancer.     

Results of radical prostatectomy in men with clinically localized prostate cancer

OBJECTIVE: To assess the results of radical prostatectomy in men with early prostate cancer. DESIGN: Retrospective, nonrandomized, multi-institutional pooled analysis. SETTING: Eight university medical centers in the United States and Europe. PATIENTS: A total of 2758 men with stage Tl and T2 prostatic cancer. MAIN OUTCOME MEASURES: Disease-specific and metastasis-free survival rates. RESULTS: Tumor grade was the most important preoperative factor in determining outcome. Disease-specific survival 10 years following surgery and associated 95% confidence intervals were 94% (range, 87%-98%), 80% (range, 74%-85%), and 77% (range, 65%-86%) for those men with grade 1, 2, and 3 tumors, respectively. Metastasis-free survival at 10 years was 87% (range, 78%-92%), 68% (range, 62%-73%), and 52% (range, 38%-64%) for patients with grade 1, 2, and 3 cancers, respectively. CONCLUSIONS: Radical prostatectomy leads to high 10-year disease-specific survival rates in men with all tumor grades. However, caution is needed in comparing these results with similar studies of alternative treatment strategies, such as watchful waiting, due to the inherent potential biases in uncontrolled trials. Nevertheless, these results offer the best currently available estimates of 10-year outcome of radical prostatectomy in men with clinically localized prostate cancer and may be useful in counseling patients with early malignancy.     

Significance of CT in the detection of regional lymph node metastases in colorectal carcinoma

PURPOSE: For preoperative staging of colorectal cancer a CT scan is frequently performed. This report examines the sensitivity of CT for regional lymph node metastasis of colorectal cancer using different criteria. MATERIALS AND METHODS: Preoperative CT scans of 153 patients with colorectal cancer were analyzed using different criteria for N1. The results were then compared to the postoperative histological findings. RESULTS: For N1 = lymph nodes (LN) > 1 cm the sensitivity was 47%. For N1 = LN > 1 cm or an increased number of LN < 1 cm the sensitivity was 71%. In patients with a primary tumor seen on CT, sensitivity rose to 87%. DISCUSSION: Evidence of regional nodal metastatic disease is only relevant for rectal cancer, colon polyps, and for locally excised tumors when considering present surgical concepts for the treatment of colorectal cancer. In these cases CT analysis using the broadened criteria for N1 proposes a valuable argument regarding possible preoperative radiotherapy or an operative revision.