George E. Reese

Diagnostic Precision of Fecal Calprotectin for Inflammatory Bowel Disease and Colorectal Malignancy

OBJECTIVES:Fecal calprotectin (FC) is a relatively new marker of intraluminal intestinal inflammation. Using meta-analytical techniques, the study aimed to evaluate the diagnostic precision of FC for inflammatory bowel disease (IBD) and colorectal cancer (CRC) in adults and children.METHODS:Quantitative meta-analysis was performed on prospective studies, comparing FC levels against the histological diagnosis. Sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated for each study. Summary receiver-operating characteristic (sROC) curves and subgroup analysis were undertaken. Study quality and heterogeneity were evaluated.RESULTS:Thirty studies of 5,983 patients were included. FC levels in patients with IBD were higher by 219.2 micrograms per gram (μg/g) compared with normal patients (P < 0.001). sROC curve analysis showed a sensitivity of 0.95 (95% CI 0.93–0.97), specificity of 0.91 (95% CI 0.86–0.91), and an area under the curve (AUC) of 0.95 for the diagnosis of IBD. Patients with colorectal neoplasia had nonsignificantly higher FC levels by 132.2 μg/g compared with noncancer controls (P = 0.18). Sensitivity and specificity of FC for the diagnosis of CRC were 0.36 and 0.71, respectively, with an AUC of 0.66. The diagnostic precision of FC for IBD was higher in children than adults with better accuracy at a cutoff level of 100 μg/g versus 50 μg/g. Sensitivity analysis and metaregression analysis did not significantly alter the results.CONCLUSIONS:FC cannot be recommended as a screening test for CRC in the general population. FC appeared to offer a good diagnostic precision in distinguishing IBD from non-IBD diagnoses, with higher precision at a cutoff of 100 μg/g.

The Risk of Cancer in Patients with Crohn’s Disease

PurposeThe risk of cancer in patients with Crohn’s disease is not well defined. Using meta-analytical techniques, the present study was designed to quantify the risk of intestinal, extraintestinal, and hemopoietic malignancies in such patients.MethodsA literature search identified 34 studies of 60,122 patients with Crohn’s disease. The incidence and relative risk of cancer were calculated for patients with Crohn’s disease and compared with the baseline population of patients without Crohn’s disease. Overall pooled estimates, with 95 percent confidence intervals, were obtained, using a random-effects model.ResultsThe relative risk of small bowel, colorectal, extraintestinal cancer, and lymphoma compared with the baseline population was 28.4 (95 percent confidence interval, 14.46–55.66), 2.4 (95 percent confidence interval, 1.56–4.36), 1.27 (95 percent confidence interval, 1.1–1.47), and 1.42 (95 percent confidence interval, 1.16–1.73), respectively. On subgroup analysis, patients with Crohn’s disease had an increased risk of colon cancer (relative risk, 2.59; 95 percent confidence interval, 1.54–4.36) but not of rectal cancer (relative risk, 1.46; 95 percent confidence interval, 0.8–2.55). There was significant association between the anatomic location of the diseased bowel and the risk of cancer in that segment. The risk of small bowel cancer and colorectal cancer was found to be higher in North America and the United Kingdom than in Scandinavian countries with no evidence of temporal changes in the cancer incidence.ConclusionsThe present meta-analysis demonstrated an increased risk of small bowel, colon, extraintestinal cancers, and lymphoma in patients with Crohn’s disease. Patients with extensive colonic disease that has been present from a young age should be candidates for endoscopic surveillance; however, further data are required to evaluate the risk of neoplasia over time.

Diagnostic precision of anti-Saccharomyces cerevisiae antibodies and perinuclear antineutrophil cytoplasmic antibodies in inflammatory bowel disease

AIMS:The aim of this study was to assess the diagnostic precision of antiSaccharomyces cerevisiae (ASCA) and perinuclear antineutrophil cytoplasmic antibodies (pANCA) in inflammatory bowel disease (IBD) and evaluate their discriminative ability between ulcerative colitis (UC) and Crohns disease (CD).METHODS:Meta-analysis of studies reporting on ASCA and pANCA in IBD was performed. Sensitivity, specificity, and likelihood ratios (LR+, LR–) were calculated for different test combinations for CD, UC, and for IBD compared with controls. Meta-regression was used to analyze the effect of age, DNAse, colonic CD, and assay type.RESULTS:Sixty studies comprising 3,841 UC and 4,019 CD patients were included. The ASCA+ with pANCA– test offered the best sensitivity for CD (54.6%) with 92.8% specificity and an area under the ROC (receiver operating characteristic) curve (AUC) of 0.85 (LR+ = 6.5, LR– = 0.5). Sensitivity and specificity of pANCA+ tests for UC were 55.3% and 88.5%, respectively (AUC of 0.82; LR+ = 4.5, LR– = 0.5). Sensitivity and specificity were improved to 70.3% and 93.4% in a pediatric subgroup when combined with an ASCA– test. Meta-regression analysis showed decreased diagnostic precision of ASCA for isolated colonic CD (RDOR = 0.3).CONCLUSIONS:ASCA and pANCA testing are specific but not sensitive for CD and UC. It may be particularly useful for differentiating between CD and UC in the pediatric population.

Comparison of outcomes following ileostomy versus colostomy for defunctioning colorectal anastomoses.

The present study evaluated outcomes of patients undergoing proximal diversion using either a loop ileostomy or loop colostomy following distal colorectal resection for malignant and non-malignant disease. A literature search of the Medline, Ovid, Embase and Cochrane databases was performed to identify studies published between 1966 and 2006, comparing loop ileostomy and loop colostomy to protect a distal colorectal anastomosis. A random effect meta-analytical technique was used and sensitivity analysis performed on studies published since 2000, higher quality papers, those reporting on 70 or more patients, and those reporting outcomes following colorectal cancer resections. Seven studies, including three randomised controlled trials, satisfied the inclusion criteria. Outcomes of a total of 1,204 patients were analysed, of whom 719 (59.7%) underwent defunctioning loop ileostomy. High stoma output was more common following ileostomy formation (OR = 5.39, 95% CI: 1.11, 26.12, P = 0.04), but wound infections following their reversal were significantly fewer (OR = 0.21, 95% CI: 0.07, 0.62, P = 0.004). Overall complications were less frequent for ileostomy patients in the subgroup of high quality studies (OR = 0.22, 95% CI: 0.08, 0.59, P = 0.003). The results of this meta-analysis suggest that ileostomy may be preferable to colostomy when used to defunction a distal colorectal anastomosis. Wound infections following stoma reversal were reduced, as were overall stoma-related complications and incisional hernia following stoma reversal for ileostomy patients in high quality studies.

A meta-analysis comparing incidence of recurrence and indication for reoperation after surgery for perforating versus nonperforating Crohn's disease.

OBJECTIVE:This study used meta-analytical techniques to compare the incidence of recurrence and the indication for reoperation in patients with Crohns disease (CD) who underwent their first operation, due to perforating disease versus patients who underwent their first operation due to nonperforating disease.METHODS:Comparative studies published between 1988 and 2005 of perforating versus nonperforating CD were included. Using a random effects model, end points evaluated were recurrence of CD given as reoperation, and the indication for reoperation, i.e., perforating or nonperforating. Heterogeneity (HG) was assessed and a sensitivity analysis was performed to account for bias in patient selection.RESULTS:Thirteen studies (12 nonrandomized retrospective, 1 nonrandomized prospective) reported on 3,044 patients, of which 1,337 (43.9%) had perforating indications (P group) and 1,707 (56.1%) had nonperforating indications (NP group) for surgery. The recurrence was found to be significantly higher in the P group compared to the NP group (HR 1.50, P = 0.002), with significant HG among studies (P < 0.001). The recurrence remained significantly higher in the P group compared with the NP group during sensitivity analysis of high-quality studies (HR 1.47, P = 0.005) and more recent studies (HR 1.51, P = 0.05), but still demonstrating significant HG (P = 0.08 and P < 0.001, respectively). At reoperation, concordance was found in the disease type of those patients re-presenting with perforating disease (OR 5.93, P < 0.001, without significant HG among studies P = 0.15) and those with nonperforating disease (OR 5.73, P < 0.001, with significant HG among studies P < 0.001). Concordance in disease type remained when considering only high-quality studies (P: OR 7.48, P < 0.001; NP: OR 7.48, P < 0.001) and more recent studies (P: OR 5.95, P < 0.001; NP: OR 5.95, P < 0.001), both not associated with HG among studies (P = 0.47 and P = 0.60, respectively).CONCLUSIONS:The indication for reoperation in CD tends to be the same as the primary operation, i.e., perforating disease tends to re-present as perforating disease, and nonperforating as nonperforating. Also, perforating CD appears to be associated with a higher recurrence rate compared with nonperforating CD. However, because of significant HG among studies, further studies should be undertaken to confirm this finding.

Terahertz pulsed imaging of freshly excised human colonic tissues

We present the results from a feasibility study which measures properties in the terahertz frequency range of excised cancerous, dysplastic and healthy colonic tissues from 30 patients. We compare their absorption and refractive index spectra to identify trends which may enable different tissue types to be distinguished. In addition, we present statistical models based on variations between up to 17 parameters calculated from the reflected time and frequency domain signals of all the measured tissues. These models produce a sensitivity of 82% and a specificity of 77% in distinguishing between healthy and all diseased tissues and a sensitivity of 89% and a specificity of 71% in distinguishing between dysplastic and healthy tissues. The contrast between the tissue types was supported by histological staining studies which showed an increased vascularity in regions of increased terahertz absorption.

The Effect of Crohn’s Disease on Outcomes After Restorative Proctocolectomy

PurposeThis study was designed to compare postoperative adverse events and functional outcomes after ileal pouch-anal anastomosis between patients with Crohn’s disease and those with non-Crohn’s disease diagnoses.MethodsA literature search was performed to identify studies published between 1980 and 2005 comparing outcomes of patients undergoing ileal pouch-anal anastomosis for Crohn’s disease, ulcerative colitis, and indeterminate colitis. Random-effect, meta-analytical techniques were used and sensitivity analysis was performed.ResultsTen studies comprising 3,103 patients (Crohn’s disease=225; ulcerative colitis=2,711; indeterminate colitis=167) were included. Patients with Crohn’s disease developed more anastomotic strictures than non-Crohn’s disease diagnoses (odds ratio, 2.12; P=0.05) and experienced pouch failure more frequently than patients with ulcerative colitis (Crohn’s disease vs. ulcerative colitis: 32 vs. 4.8 percent, P<0.001; Crohn’s disease vs. indeterminate colitis: 38 vs. 5 percent, P<0.001). Urgency was more common in Crohn’s disease compared with non-Crohn’s disease: 19 vs. 11 percent (P=0.02). Incontinence occurred more frequently in Crohn’s disease compared with non-Crohn’s disease patients: 19 vs. 10 percent (odds ratio, 2.4; P=0.01). Twenty-four-hour stool frequency did not differ significantly between Crohn’s disease, ulcerative colitis, or indeterminate colitis. Patients with isolated colonic Crohn’s disease were not significantly at increased risk of postoperative complications or pouch failure (P=0.06).ConclusionsPatients with Crohn’s disease undergoing ileal pouch-anal anastomosis should be appropriately counseled toward poorer functional outcomes and higher failure compared with non-Crohn’s disease patients. It maybe possible to preoperatively select patients with isolated colonic Crohn’s disease who may benefit from ileal pouch-anal anastomosis with acceptable adverse outcomes.

Strictureplasty vs resection in small bowel Crohn's disease: an evaluation of short-term outcomes and recurrence

Aim  To compare postoperative adverse events and recurrence following strictureplasty or bowel resection in patients with small bowel Crohns disease (CD).

Meta-analysis of the role of granulomas in the recurrence of Crohn disease.

PURPOSE: This study used meta-analytical techniques to compare the recurrence of granulomatous vs nongranulomatous Crohn disease. METHODS: Comparative studies published between 1954 and 2007 of granulomatous vs nongranulomatous Crohn disease were included. Using a random effects model, end points evaluated were the number of recurrences and reoperations, and the time to recurrence and reoperation, of granulomatous vs nongranulomatous Crohn disease. Heterogeneity was assessed and sensitivity analysis was performed to account for bias in patient selection. RESULTS: Twenty-one studies (14 nonrandomized retrospective, 7 nonrandomized prospective) reported on 2236 patients with Crohn disease, of whom 1050 (47.0%) had granulomas (granulomatous group) and 1186 (53.0%) had no granulomas (nongranulomatous group). The number of recurrences and reoperations was found to be significantly higher in the granulomatous group compared to the nongranulomatous group (odds ratio 1.37, P = .04; odds ratio 2.38, P < .001; respectively), with significant heterogeneity between studies (P = .06; P < .001; respectively). The time to recurrence and reoperation was significantly shorter in the granulomatous group compared with the nongranulomatous group (hazard ratio 1.63, P = .001; hazard ratio 1.62, P = .002; respectively), with no significant heterogeneity between studies. The number of recurrences and reoperations remained significantly higher in the granulomatous group compared to the nongranulomatous group during sensitivity analysis of higher-quality studies, more recent studies, and studies with a larger group of patients. CONCLUSIONS: Granulomatous Crohn disease appears to be associated with a higher number of recurrences and reoperations and a shorter time to recurrence and reoperation compared to nongranulomatous Crohn disease. Because of significant heterogeneity between studies, further studies should be undertaken to confirm these findings.

Terahertz Time-Domain Spectroscopy of Human Blood

In the continuing development of terahertz technology to enable the determination of tissue pathologies in real-time during surgical procedures, it is important to distinguish the measured terahertz signal from biomaterials and fluids, such as blood, which may mask the signal from tissues of interest. In this paper, we present the frequency-dependent absorption coefficients, refractive indices, and Debye relaxation times of whole blood, red blood cells, plasma, and a thrombus.