Rectal biopsy as a prognostic guide in Crohn's colitis

ECCO Position on Harmonisation of Crohn's Disease Mucosal Histopathology

In inflammatory bowel disease [IBD], mucosal healing is a major therapeutic target and a reliable predictor of clinical course. However, endoscopic mucosal healing is not synonymous with histological healing, and the additional benefits of including histological remission as a target are unclear. In Crohn´s disease [CD], there are few studies highlighting the value of histological remission as a therapeutic target. Histological activity can persist in CD patients who are in endoscopic remission, and the absence of histological activity may be associated with lower relapse rates. Therefore, standardisation of procedures to evaluate CD histological activity is desirable. Topics that would benefit from standardisation and harmonisation include biopsy procedures, biopsy processing techniques, the content of histological scores, and the definitions of histological remission, histological response, and histological activity. In line with these needs, the European Crohn's and Colitis Organisation [ECCO] assembled a consensus group with the objective of developing position statements on CD histology based on published evidence and expert consensus. There was agreement that definitions of histological remission should include absence of erosion, ulceration, and mucosal neutrophils; that the absence of neutrophilic inflammation is an appropriate histological target in CD; that CD histological scores, such as the Global Histological Disease Activity Score, lack formal validation; and that histological scoring systems for ulcerative colitis, including the Geboes Score, Robarts Histopathology Index, and Nancy Histological Index, can be used for scoring intestinal biopsies in CD patients.

An expert consensus to standardise the assessment of histological disease activity in Crohn's disease clinical trials

BACKGROUND

Targeting histological remission or response in Crohn's disease (CD) is not recommended in clinical practice guidelines or as an outcome in clinical trials due to uncertainties regarding index validity and prognostic relevance.

AIMS

To conduct a modified RAND/University of California Los Angeles appropriateness process with the goal of producing a framework to standardise histological assessment of CD activity in clinical trials.

METHODS

A total of 115 statements generated from literature review and expert opinion were rated on a scale of 1-9 by a panel of 11 histopathologists and 6 gastroenterologists. Statements were classified as inappropriate, uncertain or appropriate based upon the median panel rating and degree of disagreement.

RESULTS

The panellists considered it important to measure histological activity in clinical trials to determine efficacy and that absence of neutrophilic inflammation is an appropriate histological target. They were uncertain whether the Global Histological Activity Score was an appropriate instrument for measuring histological activity. The Geboes Score and Robarts Histopathology Index were considered appropriate. Two biopsies from five segments should be biopsied, and the colon and the ileum should be analysed separately for all indices. Endoscopic mucosal appearance should guide biopsy procurement site with biopsies taken from the ulcer edge, or the most macroscopically inflamed area in the absence of ulcers.

CONCLUSION

We evaluated the appropriateness of items for assessing histological disease activity in CD clinical trials. These items will be used to develop a novel histological index.

Histological scores in inflammatory bowel disease

The role of histology in inflammatory bowel disease (IBD) has not yet been well defined. Endoscopic mucosal healing has been proposed as a predictor of the clinical course of IBD and it is indeed considered one of the main therapeutic targets. However, it does not necessarily imply histological healing. Histological remission has been reported to be associated with a better clinical outcome than endoscopic remission only in IBD patients. These observations support the view that histology plays a role as a potential therapeutic target in Crohn's disease and ulcerative colitis. Histological scores being able to quantify the degree of microscopic activity are needed for this purpose. In the era of biologics, indication for proper treatment may benefit from the assessment of clinical and endoscopic activity, as well as histological scores. Such scores may allow us to quantify the microscopic mucosal response to treatment and to define complete healing in IBD. A validated histological score in IBD may lead to the definition of microscopic activity in clinical practice, trials and investigational settings. Several attempts to develop such scores have been reported, but few are currently used and none is applied worldwide in clinical practice. The present review summarizes the main histological scores currently used for assessing IBD activity.

What is the role of histopathology in the evaluation of disease activity in Crohn's disease?

Assessment of disease activity is essential for developing and determining appropriate therapy in patients with Crohn's disease. Currently, clinical and endoscopic treatment targets have been proposed, whereas histologic assessment of disease activity is not recommended in expert guidelines. Histologic assessment of disease activity has emerged as an important tool in ulcerative colitis as persistent histological inflammation is associated with clinical relapse, corticosteroid use, hospitalisation, and development of dysplasia. Similar data for Crohn's disease is limited but emerging literature suggests that histologic evaluation of disease activity may have value. This review summarizes the recent literature regarding histologic evaluation of disease activity in Crohn's disease. Correlation between histologic, endoscopic, and other markers of disease activity are discussed. Histologic scoring systems in Crohn's disease are described and practical guidance is provided to gastroenterologists and pathologists on how to report and interpret histologic data.

Histologic scoring indices for evaluation of disease activity in Crohn's disease

BACKGROUND

Histologic assessment of mucosal disease activity has been increasingly used in clinical trials of treatment for Crohn's disease. However, the operating properties of the currently existing histologic scoring indices remain unclear.

OBJECTIVES

A systematic review was undertaken to evaluate the development and operating characteristics of available histologic disease activity indices in Crohn's disease.

SEARCH METHODS

Electronic searches of MEDLINE, EMBASE, PubMed, and the Cochrane Library (CENTRAL) databases from inception to 20 July 2016 were supplemented by manual reviews of bibliographies and abstracts submitted to major gastroenterology meetings (Digestive Disease Week, United European Gastroenterology Week, European Crohn's and Colitis Organisation).

SELECTION CRITERIA

Any study design (e.g. randomised controlled trial, cohort study, case series) that evaluated a histologic disease activity index in patients with Crohn's disease was considered for inclusion. Study participants included adult patients (> 16 years), diagnosed with Crohn's disease using conventional clinical, radiographic or endoscopic criteria.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed the titles and abstracts of the studies identified from the literature search. The full text of potentially relevant citations were reviewed for inclusion and the study investigators were contacted as needed for clarification. Any disagreements regarding study eligibility were resolved by discussion and consensus with a third author.Two authors independently extracted and recorded data using a standard form. The following data were recorded from each eligible study: number of patients enrolled; number of patients per treatment arm; patient characteristics: age and gender distribution; description of histologic disease activity index utilized; and outcomes such as content validity, construct validity, criterion validity, responsiveness, intra-rater reliability, inter-rater reliability, and feasibility.

MAIN RESULTS

Sixteen reports of 14 studies describing 14 different numerical histological indices fulfilled the inclusion criteria.Inter-rater reliability was assessed in one study. For the Naini and Cortina Score, estimates of correlation were 'almost perfect', ranging from r = 0.94 to 0.96. The methodological quality of this study with respect to reliability was 'good'.With respect to validity, correlation estimates between various histological scoring systems and Crohn's disease activity as measured by objective markers of inflammation (including C-reactive protein, erythrocyte sedimentation rate, fecal calprotectin and fecal lactoferrin); endoscopic disease activity scores; clinical disease activity scores; and quality of life questionnaires were reported. Comparisons between histologic scoring indices and endoscopic scoring indices ranged from no correlation to 'substantial' (r = 0.779). The methodological quality of the studies that explored validity ranged form 'poor' to 'good'.Responsiveness data were available in seven studies. After subjects were administered a treatment of known efficacy, statistically significant change in the index score was demonstrated in five studies with respect to six indices. Two studies failed to indicate whether there was statistically significant change in the index score post-treatment. With regard to methodological quality, six of the studies were rated as 'poor' and one of the studies was rated as 'fair'.Feasibility was assessed by one study. The Naini and Cortina Score was shown to be simple to use and feasible for every given case.

AUTHORS' CONCLUSIONS

Currently there is no fully validated histological scoring index for evaluation of Crohn's disease activity. Development of a validated histological scoring index for Crohn's disease is a clinical and research priority.

Clinical Implications of Histologic Abnormalities in Ileocolonic Biopsies of Patients With Crohn's Disease in Remission

BACKGROUND

For patients with Crohn's disease (CD) who have colonoscopy during periods of clinical remission, the utility of taking ileocolonic biopsy specimens to assess disease activity is disputed.

GOALS

We explored the clinical implications of histologic disease activity in such patients.

STUDY

We reviewed medical records of CD patients who underwent elective colonoscopy while in clinical remission at our VA Medical Center from 2000 to 2013, and who had at least 6 months of follow-up. We correlated endoscopic and histologic disease activity with the subsequent development of flares.

RESULTS

We identified 62 CD patients who had a total of 103 colonoscopies during clinical remission; 55 colonoscopies revealed complete endoscopic healing and 48 showed active disease. Flares within 6, 12, and 24 months of colonoscopy were not more common in patients with endoscopic activity than those with complete endoscopic healing. In contrast, patients with any of 5 histologic features of active inflammation (erosions, cryptitis, crypt abscess, increased neutrophils, or increased eosinophils in the lamina propria) had more flares than patients without those changes (P<0.05). Among the individual histologic features, an increase in eosinophils or neutrophils in the lamina propria and cryptitis were associated with higher flare rates (P<0.05).

CONCLUSIONS

For CD patients who have a colonoscopy while in clinical remission, biopsy seems to provide important prognostic information beyond that provided by endoscopic assessment of disease activity alone. In particular, increased eosinophils or neutrophils in the lamina propria and cryptitis are strongly associated with an increased risk of clinical flares within 1 to 2 years.

Assessment of histologic disease activity in Crohn's disease: a systematic review

BACKGROUND

Crohn's disease (CD) is an idiopathic, chronic, transmural inflammatory disorder of the gastrointestinal tract. Because mucosal involvement is near-universal, endoscopic healing has emerged as an important aspect in improving outcome. However, resolution of histologic disease activity has potential to convey additional benefit beyond that attained with endoscopic healing alone. Validated scoring systems of histologic disease activity are required to further assess this possibility. The aim of this study was to systematically review the existing histologic disease activity indices (HDAI) for CD and to assess their operating properties and potential use as outcome measures in clinical trials.

METHODS

MEDLINE (Ovid), EMBASE (Ovid), PubMed, the Cochrane Library (CENTRAL), and Digestive Disease Week (DDW) abstracts were searched from 1981 to April 2013 for applicable studies to identify relevant studies for review and analysis.

RESULTS

In total, 3732 citations were screened to obtain 89 articles for inclusion. Sixty-six HDAIs were characterized as either stepwise or numerical instruments. These HDAIs were used for either assessment of response to medical therapy or for comparison with biomarkers or imaging tests. None of the HDAIs identified was developed according to currently accepted methods for developing evaluative instruments, and none have been formally validated.

CONCLUSIONS

Measurement of histologic disease activity has potential value in CD; however, no validated measures are available. Additional research is needed to develop a methodologically rigorous instrument for use in clinical investigation and potentially for clinical practice.

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.

Segmental colonoscopic biopsies in the differentiation of ileocolic tuberculosis from Crohn's disease

BACKGROUND AND AIM

The differentiation between Crohn's disease (CD) and tuberculosis (TB) of the intestine can be difficult in areas where both diseases occur. The present study examined histological criteria that would enable the diagnosis in mucosal biopsies.

METHODS

Colonoscopic biopsies from 33 patients with TB and 31 patients with CD were examined for several specific histological features and their distribution.

RESULTS

The salient distinguishing features of TB were granulomas larger than 400 microm in maximum dimension, more than four sites of granulomatous inflammation per site, cessation, a band of epithelioid histiocytes in ulcer bases and location of granulomas in the caecum. The salient features of CD were granulomas not showing any of the above features, focally enhanced colitis, pericryptal granulomatous inflammation, and the presence of architectural alteration/activity/chronic inflammation/deep ulceration at sites that did not show granulomatous response in the same or adjacent segments. Although granulomas in CD were distributed throughout the colon, they were more frequent in the rectosigmoid than in TB. All biopsies from endoscopically abnormal sites did not show distinguishing features of TB or CD, emphasizing the need for multiple biopsies. There was an accrual in the number of diagnoses made with increasing numbers of biopsies from rectum to ileum.

CONCLUSIONS

Histology of mucosal biopsies can aid in the differentiation of TB from CD, but multiple biopsies from different colonic segments are important for complete evaluation.

Histology of the lower intestinal tract in Crohn's disease of children and adolescents. Multicentric Paediatric Crohn's Disease Study

Serial sections of 1047 colonic and rectal biopsies from 385 children and adolescents suffering from Crohn's disease were studied histologically. Inflammatory alterations were seen in 76% of the biopsies and 84% of the patients. Incidence of inflammatory infiltration, of crypt abscesses, of erosions, and of ulcers decrease from caecum to rectum were studied. The incidence of granulomas falls along the colon but rises in the rectum. The occurrence of granuloma depends rather on the severity of the inflammation than on the biopsy site. Granulomas are present in 26% of the biopsies and 42% of the patients. Compared to adults, the incidence was twofold in children. Discontinuous type of infiltration, density of infiltration, crypt abscesses, rectal erosions prevail in children, diffuse type of infiltration, and colonic ulcers in adults. Incidence of granulomas is reduced after the second year of illness and after the 16th year of life. The number of granulomas per mm3 biopsy is increased in children, their average size in adults.

The granuloma in Crohn's disease. A bioptical study

Serial sections of 1434 colonic and rectal biopsies of 347 patients with Crohn's disease were performed. The relationship between the incidence of granulomas and the inflammatory alterations of the mucosa and some clinical parameters was studied. The presence of granulomas depends on the severity of inflammatory alterations and not on the site of the biopsy. The number of granulomas per mm3 increases from caecum to rectum. The incidence of granulomas decreases with age, duration of illness and under a conservative therapy. If several biopsies, taken at the same or at different times, are studied, granulomas can be found in 40-50% of these patients.