Colonoscopy and the detection of dysplasia in patients with longstanding ulcerative colitis

Detecting dysplasia using white light endoscopy or chromoendoscopy in ulcerative colitis patients without primary sclerosing cholangitis: A systematic review and meta-analysis

BACKGROUND

Endoscopic examinations are a vital diagnostic tool for dysplasia. Establishing the precision of different modes of examination is essential due to the disparate pick-up rates of dysplasia.

OBJECTIVE

The aim of this article was to establish the pick-up rates of dysplastic or cancerous lesions using white light endoscopy (WLE) and random/targeted biopsies, or chromoendoscopy (CE), in patients with ulcerative colitis (UC) without primary sclerosing (PSC) or Crohn's disease (CD).

DATA SOURCES

A systematic review to identify all studies up to November 2017, without language restriction, was conducted from PubMed, the Cochrane Controlled Trials Register (1960-2017), MEDLINE, CINAHL and EMBASE (1981-2017). MeSH and text word terms used included "ulcerative colitis", "dysplasia", "random biopsy", "targeted biopsy", "colonoscopy", "white light", and "chromoendoscopy". Further searches were performed using the bibliographies of these articles.

STUDY SELECTION

All studies reporting on colonoscopy detection rates of dysplasia and cancers in UC without involvement of PSC or CD were included. There was no age restriction to include patients.

DATA EXTRACTION

Outcome data were extracted by 2 authors independently using outcome measures defined a priori. Quality assessment was performed using the Newcastle-Ottawa scales.

DATA SYNTHESIS

Data were extracted and analysed according to meta-analytical techniques using comprehensive meta-analysis. The pooled overall pick-up rate of dysplastic/cancerous lesions on WLE random biopsies was 5.6% [Event rate 0.06 (0.01, 0.23), df = 4, I2 = 94%]. Using a combined random and targeted approach with WLE the incidence was 5.1% [Event rate 0.05 (0.03, 0.09), df = 4, I2 = 96%]. One study reported on CE and found a 7% pick-up rate for dysplastic lesions.

CONCLUSIONS

Endoscopic examination of UC patients without PSC identifies dysplastic or cancerous lesions in 5-7% of cases. WLE and random biopsies may pick-up a similar number of lesions to targeted biopsies, however the number of biopsies may need to be greater to achieve this equivalence. CE has a slightly higher pick-up rate. Further comparative studies are required to strengthen the body of evidence.

The risk of colorectal cancer in ulcerative colitis: a meta-analysis

BACKGROUND AND AIMS

Controversy surrounds the risk of colorectal cancer (CRC) in ulcerative colitis (UC). Many studies have investigated this risk and reported widely varying rates.

METHODS

A literature search using Medline with the explosion of references identified 194 studies. Of these, 116 met our inclusion criteria from which the number of patients and cancers detected could be extracted. Overall pooled estimates, with 95% confidence intervals (CI), of cancer prevalence and incidence were obtained using a random effects model on either the log odds or log incidence scale, as appropriate.

RESULTS

The overall prevalence of CRC in any UC patient, based on 116 studies, was estimated to be 3.7% (95% CI 3.2-4.2%). Of the 116 studies, 41 reported colitis duration. From these the overall incidence rate was 3/1000 person years duration (pyd), (95% CI 2/1000 to 4/1000). The overall incidence rate for any child was 6/1000 pyd (95% CI 3/1000 to 13/1000). Of the 41 studies, 19 reported results stratified into 10 year intervals of disease duration. For the first 10 years the incidence rate was 2/1000 pyd (95% CI 1/1000 to 2/1000), for the second decade the incidence rate was estimated to be 7/1000 pyd (95% CI 4/1000 to 12/1000), and in the third decade the incidence rate was 12/1000 pyd (95% CI 7/1000 to 19/1000). These incidence rates corresponded to cumulative probabilities of 2% by 10 years, 8% by 20 years, and 18% by 30 years. The worldwide cancer incidence rates varied geographically, being 5/1000 pyd in the USA, 4/1000 pyd in the UK, and 2/1000 pyd in Scandinavia and other countries. Over time the cancer risk has increased since 1955 but this finding was not significant (p=0.8).

CONCLUSIONS

Using new meta-analysis techniques we determined the risk of CRC in UC by decade of disease and defined the risk in pancolitics and children. We found a non-significant increase in risk over time and estimated how risk varies with geography.

Dysplasia complicating chronic ulcerative colitis: is immediate colectomy warranted?

PURPOSE

Inflammatory bowel disease surveillance strategies are designed to identify patients at greater than average risk for the development of invasive colonic carcinoma. Colonoscopic detection of mucosal dysplasia is considered the best available surveillance tool. However, the usefulness of dysplasia as a marker for cancer is uncertain. Furthermore, when dysplasia is found some suggest immediate colectomy, whereas others opt for continued surveillance. The aim of this study is to determine whether an association between dysplasia grade and cancer exists in patients with chronic ulcerative colitis, to ascertain the sensitivity, specificity, and positive predictive value of dysplasia as a cancer marker, and to clarify what action to take once dysplasia is discovered.

METHODS

The pathology reports of 590 patients who underwent total proctocolectomy or restorative proctocolectomy for chronic ulcerative colitis were reviewed for dysplasia, grade of dysplasia, presence of carcinoma, and tumor stage. One hundred sixty of these patients had undergone colonoscopic examination within the year before surgery. Findings from these studies were also reviewed.

RESULTS

Seventy-seven specimens (13.1 percent) contained at least one focus of dysplasia. Invasive cancers were found in 38 specimens (6.4 percent). Cancers were significantly more common among specimens with dysplastic changes (33/77 vs. 5/513; P < 0.001). Specimens with dysplasia of any grade were 36 times more likely to harbor invasive carcinoma. Stage III disease was found in association with indefinite or low-grade dysplasia in 5 of 26 (19.2 percent) of cases. Tumor stage did not correlate with dysplasia grade. Preoperative colonoscopy identified neoplastic changes in 57 (69.5 percent) cases. Dysplasia, cancer or both were missed in 25 cases. Lesions were correctly identified in only 31 (39.7 percent) of cases. Colonoscopically diagnosed dysplasia as a marker for synchronous cancer had a sensitivity of 81 percent and a specificity of 79 percent. The positive predictive value of a finding of preoperative dysplasia of any grade was 50 percent. The positive predictive value of a finding of low-grade dysplasia was 70 percent.

CONCLUSIONS

Dysplasia is an unreliable marker for the detection of synchronous carcinoma. However, when dysplasia of any grade is discovered at colonoscopy, the probability of a coexistent carcinoma is relatively high. Colonoscopic evidence of low-grade dysplasia has a higher positive predictive value than either dysplasia associated mass or lesion or high-grade dysplasia. Dysplasia grade does not predict tumor stage. Because advanced cancer can be found in association with dysplastic changes of any grade, confirmed dysplasia of any grade is an indication for colectomy.

Failure of colonoscopic surveillance in ulcerative colitis

A prospective surveillance programme for patients with longstanding (> = 8 years), extensive (> = splenic flexure) ulcerative colitis was undertaken between 1978 and 1990. It comprised annual colonoscopy with pancolonic biopsy. One hundred and sixty patients were entered into the programme and had 739 colonoscopies (4.6 colonoscopies per patient; 709 patient years follow up). Eight eight per cent of examinations reached the right colon. There was no procedure related death. One Dukes's A cancer was detected. Forty one patients (25%) defaulted. Of these 25 remain well; 13 are unaccounted for, and one died from colonic cancer. One patient had colectomy for medical reasons, and another died of carcinoma of the pancreas. Retrospectively an additional 16 eligible patients were identified who had not been recruited. Of these, 14 remain well, two are unaccounted for. None developed colonic cancer. Four patients refused colonoscopy. All remain well. Over the same period seven other cases of colonic cancer were found in association with ulcerative colitis, two in patients who had erroneously been diagnosed as having only proctitis and were therefore not entered into the programme, but were found at operation to have total colitis, one in a patient with colitis of seven years duration, and four patients who had previously attended the clinic but had been lost to follow up before 1978 and then had represented with new symptoms during the surveillance period. Thus, of the nine colitis related cancers diagnosed in this centre during the study period only one was detected by the surveillance programme. The results of this large study, a a review of published works, cast doubts on the effectiveness of colonoscopic surveillance programmes in detecting colorectal cancer in patients with ulcerative colitis.

Spectroscopic diagnosis of colonic dysplasia

We have developed a method for defining diagnostic algorithms for pathologic conditions based on fluorescence spectroscopy. We apply this method to human colon tissue and show that fluorescence can be used to diagnose the presence or absence of colonic adenoma. This method uses fluorescence excitation-emission matrices (EEM) to identify optimal excitation regions for obtaining fluorescence emission spectra which can be used to differentiate normal and pathologic tissues. In the case of normal and adenomatous colon tissue, these were found to be: 330, 370, and 430 nm +/- 10 nm. At these excitation wavelengths, emission wavelengths for use in diagnostic algorithms are identified from average difference and ratio of the spectra from normal and pathologic tissues. In colon tissue, at 370 nm excitation, 404, 480, and 680 nm were found to be useful emission wavelengths for diagnosing the presence of adenoma in vitro. The basis of colon tissue autofluorescence was investigated using EEM of pure molecules and relevant excitation-emission maxima in the literature.

Colonoscopic surveillance in long-standing total ulcerative colitis--a 15-year follow-up study

In a 15-year surveillance program composed of 72 patients with total ulcerative colitis, 12 patients developed definite dysplasia. At endoscopy, low-grade dysplasia was detected in seven patients, high-grade in four, and a carcinoma (Dukes' stage A at operation) in one. One of the patients with high-grade dysplasia and macroscopical lesions at colonoscopy had a carcinoma (Dukes' A) detected at operation. A sequential development of dysplasia was found in seven patients. The cumulative risk of developing at least low-grade dysplasia was 14% after 25 years of disease duration. Using flow cytometric analyses, abnormal, aneuploid DNA content was detected in biopsies of 12 of 59 patients (20.3%); this correlated significantly with low-grade and high-grade dysplasia. Aneuploidy preceded dysplasia in two patients and was also detected in two dysplasia-free patients. The long-term use of colonoscopic surveillance in ulcerative colitis is a reliable way to select patients, in whom dysplasia is developing, for prophylactic surgery. Additionally, flow cytometric DNA analyses may help in the selection. The risk of missing a carcinoma until it becomes incurable appears to be low.

Screening strategies in gastrointestinal cancer

The concept of screening is based on the notion that regular examination can reduce the mortality from gastrointestinal cancer, but there is as yet little evidence that this is the case in either Barrett's esophagus or ulcerative colitis. Screening is carried out by regular endoscopy with multiple biopsies in an attempt to detect dysplasia, which has traditionally been regarded as the end point of surveillance and the time when resection should be considered. Considerable departure from these guidelines has occurred. Attempts are increasingly being made to select patients in both of these groups who might be at particular high risk of developing dysplasia because of the presence of nuclear aneuploidy, the assumption being that these patients are at particular risk of developing dysplasia and carcinoma. However, data to support stratification at this level are unavailable. In addition, there is not good agreement as to whether surveillance is indicated at all in some groups of patients such as those with less than total colitis or short-segment Barrett's esophagus. The end point of surveillance has also been questioned, with reluctance to recommend colectomy in ulcerative colitis with the finding of low-grade dysplasia, possibly because the sampling problem is so great that it may be impossible to confirm that diagnosis on repeated endoscopy and biopsy. While better markers than dysplasia may be required to predict patients at highest risk, there are currently no marker other than the development of invasive carcinoma on which the decision to resect can be based.(ABSTRACT TRUNCATED AT 250 WORDS)

Hazard rates for dysplasia and cancer in ulcerative colitis. Results from a surveillance program

The risk of colon cancer in patients with ulcerative colitis is related to the duration and extent of disease. Prior reports have suggested that patients with onset of disease in childhood have a high risk of cancer. These risk factors were analyzed in 99 patients in a surveillance program of annual colonoscopy to detect mucosal dysplasia. All patients had pancolitis for at least eight years. The mean age at symptom onset was 23.2 years and the mean duration of disease at entry was 17 years. An average of 4.2 tests/patient were performed, and 91% were completely followed through 1985. Cancer risk was expressed as the hazard rate or the annual probability that a patient free of cancer would develop cancer after survival to a given time period. The hazard rate for high-grade dysplasia or cancer in patients with pancolitis measured from symptom onset was 2.5% at 20 years, 4% at 25 years, 7% at 30 years, 13% at 35 years, and 20% at 40 years. Sex was not a significant predictor of cancer, but older age at symptom onset was a predictor of dysplasia and cancer. From these data, the annual hazard rate of developing high-grade dysplasia or cancer can be estimated in patients with pancolitis based on an individual's age at symptom onset and duration of disease.

Observer variation in the assessment of dysplasia in ulcerative colitis

Six histopathologists allocated 100 sections from patients with long-standing ulcerative colitis into four diagnostic categories, regular hyperplasia, reactive atypia, low-grade and high-grade dysplasia. Their allocations were analysed using kappa statistics, including Fleiss's multiple kappa for groups of observers, and agreement on specific diagnoses was explored by constructing a conditional probability matrix. The nature of their disagreements was investigated using coefficients for systematic and haphazard errors. Over the four diagnostic categories there was a wide range of pairwise agreement from a low of 49% up to 72% and kappa values were only 'fair' or 'moderate'. As expected, agreement over the two categories 'dysplasia' vs 'no dysplasia' was better, ranging from 68% to 84%, and for 'atypia present' (reactive atypia, low- and high-grade dysplasia) vs "no atypia' two pairings achieved over 90% and 11 pairings over 80% agreement. In view of its clinical importance, conditional agreement on high-grade dysplasia, pairwise agreement on this diagnosis ranged from 100% down to as low as 33%. However, most of these disagreements fell into the low-grade dysplasia category so that closer follow-up and further biopsies would still have been indicated. It is a truism that the basis for safe management is careful co-operation between clinicians and pathologists who have all the relevant facts and who know and trust one another's judgement. Thus, several aspects of the ideal diagnostic process cannot be evaluated in inter-observer studies and the element of artificiality should be borne in mind when applying the findings to diagnostic practice. Nevertheless, the low level of agreement on the diagnosis of high-grade dysplasia achieved by certain pairings of specialist pathologists is a disturbing outcome of this study. Inaccuracies should be minimized by a concensus approach and we therefore recommend referral of putative cases of dysplasia to interested pathologists for further opinions. We would also advocate that pathologists faced with appearances which are indefinite between reactive atypia and dysplasia, would do better to describe them in terms of "atypia, significance uncertain', so that closer surveillance is undertaken, rather than force them into more precise diagnostic categories which may be incorrect.

Ulcerative colitis. Cancer surveillance in an unselected population

An unselected series of patients with chronic ulcerative colitis from a defined catchment area underwent endoscopic and histologic cancer surveillance from 1977 to 1985. At the end point of the study, which included a total of 93 patients, there were 38 patients with total colitis of more than 10 years' duration. There was one case of colonic carcinoma, two cases of high-grade dysplasia, and no death due to colorectal cancer. We conclude that in an unselected group of patients with ulcerative colitis, the risk for colorectal dysplasia and cancer is low and that a surveillance program is reliable and can be performed at a community hospital.

Surveillance in ulcerative colitis: burdens and benefit

A review of all patients with ulcerative colitis in one health district between 1975-84 revealed an incidence and prevalence of 7.1 and 84/100,000 population respectively. One hundred and ninety five new patients were diagnosed and 313 patients seen and followed up in the clinic for 1168 patient years. None of these patients died from colitis or a complication. On routine colonoscopy three cases had high grade dysplasia and two asymptomatic carcinomas (Duke's stage A and B). Eighty four patients were known to have ulcerative colitis, but were lost to follow up from the hospital clinic; the total time they were not under hospital surveillance was 315 patient years. At the end of the study these patients were contacted or clinical details obtained from their general practitioners. Five of these patients subsequently presented with symptomatic carcinomas (two Duke's B, one Duke's C and two with metastases); three of these five patients have died from their tumours. Of 48 patients thought to have only mild colitis on initial investigation 21 (43%) had substantial colitis (and two carcinomas) on colonoscopy after eight years of disease. Therefore, patients with apparently distal colitis should be followed in the clinic as well as those with known extensive colitis. For a surveillance programme in a district general hospital, eight patients per 100,000 population need to be seen weekly, 12 colonoscopies/100,000 population need to be carried out annually and the cost for each carcinoma detected is approximately 6015 pounds.

Can histopathologists reliably assess dysplasia in chronic inflammatory bowel disease?

A copy of the standardised classification (SC) proposed for assessing dysplasia in inflammatory bowel disease was circulated to six histopathologists who were asked to apply it to 40 slides from 34 patients with ulcerative colitis to test its reproducibility. The slides were relabelled and recirculated to the pathologists at least one month later. Each was asked to state whether or not key diagnostic features were present before giving a final dysplasia score for the second assessment. Only minor interobserver and intraobserver disagreements were recorded. Pathologists were most consistent at recognising back to back glands, villous mucosal architecture, hyperchromatic nuclei, stratification of nuclei, regenerative nuclei and loss of nuclear polarity. There was poor interobserver agreement in assessing dystrophic goblet cells and columnar mucous cells. Back to back glands, hyperchromatic nuclei, loss of nuclear polarity, stratification of nuclei and columnar mucous cells were considered to be the most important features for determining the severity of dysplasia. As there was poor interobserver agreement in assessing columnar mucous cells and dystrophic goblet cells these features need to be more clearly defined or should be removed from the SC.

Screening by colonoscopy for colonic epithelial dysplasia in inflammatory bowel disease

We report the results of a prospective study of screening for colorectal epithelial dysplasia by regular colonoscopy in patients with longstanding, extensive colitis (DET group: 112 patients, 366 colonoscopies) together with the findings in all other patients with colitis who have undergone colonoscopy in our unit (non-DET group: 77 patients, 196 colonoscopies). Thirty six DET patients had dysplasia on at least one examination: two patients with high grade dysplasia (HGD) were colonoscoped on suspicion of carcinoma, one asymptomatic patient had HGD at first colonoscopy and one patient had HGD on his sixth colonoscopy, all having carcinomas resected at surgery; the remainder had low grade dysplasia (LGD). Of the DET patients, 100 constituted an ongoing surveillance group (354 colonoscopies) in which LGD was common, being seen on at least one occasion in 33% of patients (16.4% of examinations), but HGD was noted only once with a Dukes A cancer found at surgery. Six non-DET patients had dysplasia diagnosed, this being LGD in all. Even in a carefully selected group of colitics the incidence of HGD is low, but its detection may enable the removal of a colorectal carcinoma at an early and curable stage.

Lectin and mucin histochemistry as an aid to cancer surveillance in ulcerative colitis

In a preliminary study, we assessed 10 lectins for the identification of dysplasia in colectomy specimens from patients with ulcerative colitis. Peanut agglutinin (PNA) binding was found in all cases of dysplasia. In the main study the relationship between PNA staining, high iron-diamine/alcian blue (HID-AB) histochemistry, and dysplasia was investigated in 115 pre-operative colonoscopic biopsies and the subsequent resection specimens from patients with ulcerative colitis complicated by carcinoma (n = 6) and patients undergoing proctocolectomy for failure of medical management (n = 8). Peanut lectin was of no value in the assessment of pre-malignant changes or cancer risk. However, the HID-AB stain appears to clarify the interpretation of less severe pre-malignant changes and may be usefully applied to the interpretation of colonoscopic biopsies for cancer surveillance in ulcerative colitis.

Serum levels of the carcinoma-associated antigen CA 50 in ulcerative colitis

The aim was to study the serum level of the carcinoma-associated antigen CA 50 as a marker of dysplasia in ulcerative colitis. Seventy-four patients with a mean history of ulcerative colitis of 16 years (SD, 9 years) underwent colonoscopic examination of the entire colon. Dysplasia was diagnosed by light microscopy of multiple biopsy specimens obtained during colonoscopy. Increased serum levels of the antigen CA 50 were found in four patients, of whom two had no signs of dysplasia. Six out of eight patients with moderate dysplasia had serum levels of CA 50 not exceeding a reference level determined as the mean + 2 SD of the results in sera of 500 blood donors. Of 5 patients with ulcerative colitis for more than 30 years, 2 had increased levels of CA 50, whereas only 2 out of 69 with shorter disease duration did (p less than 0.02). Longitudinal studies are required to determine whether measurement of carcinoma-associated antigens will provide clinical information for the treatment of patients with ulcerative colitis.

Carcinoma in Crohn's disease of the colon

Two cases of carcinoma in Crohn's disease of the colon are reported. One patient was a 30-year-old man who had asymptomatic Crohn's ileocolitis resulting in an acute presentation due to toxic dilatation of the colon. This was preceded by a short prodromal period of four weeks, characterized by intermittent diarrhea on the basis of a coloileal tumor fistula. A mucus-secreting adenocarcinoma was present in the sigmoid colon associated with both adjacent and one nearby focus of high-grade mucosal dysplasia. Pelvic wall and abdominal metastases were present, and the patient died two months later. The other patient was a 60-year-old woman who had a nine-year history of biopsy-proven Crohn's proctocolitis. A stricture of the sigmoid colon due to Crohn's disease also harbored an invasive adenocarcinoma. The carcinoma was not evident preoperatively or on initial gross pathologic examination. The presentation and pathology of large intestinal carcinoma in Crohn's colitis are discussed and illustrated.

Large bowel mucosal dysplasia and carcinoma in ulcerative colitis

The clinicopathological details of eight cases of ulcerative colitis complicated by carcinoma of the colon are described. There was a total of 14 primary colonic cancers, six of which were not detected before pathological examination of the resection specimens. The reason for this may be related to atypical tumour growth patterns. Three occurred in flat mucosa, one in a mucosal plaque lesion, and another in polypoidal mucosa. The occurrence, distribution, and morphology of mucosal dysplasia were noted in both resection specimens and biopsies taken at varying stages before resection. Tumour was associated with normal and adjacent dysplastic mucosa of varying grades. The extent and grade of dysplasia were not reliable indicators of tumour differentiation or subsequent clinical outcome. Only two cancers were poorly differentiated. In five cases a total of 23 mucosal biopsies were taken, all less than 12 months before resection. Three rectal biopsies were graded positive for dysplasia and three colonic biopsies indefinite for dysplasia. The subsequent resection specimens showed both dysplastic and carcinomatous changes. Three rectal and 14 colonic biopsies were graded negative for dysplasia despite positive findings in the subsequent resection specimens. This anomaly is partly attributed to the patchy nature of dysplasia in colitic mucosa. Two cases illustrate the possibility of dysplasia pursuing a rapidly progressive course. The mucosal changes of ulcerative colitis were assessed using a recently introduced and standardised international classification.

Villous dysplasia. An ominous histologic sign in colitic patients

Preoperative biopsies and colectomy specimens from 40 patients with long-standing ulcerative colitis (of whom 20 had adenocarcinoma at colectomy) were searched for the presence of villous adenomatous changes with or without cellular dysplasia. Villous adenomatous changes were found in available preoperative punch biopsies in nearly 70 per cent of the patients with carcinoma, but in none of the preoperative punch biopsies from the 20 patients without cancer. Only three of the preoperative biopsies from patients with carcinoma showed severe dysplasia, and also one of the 20 colitic patients without carcinoma. The mucosal tip in villous adenomatous changes was usually covered by columnar epithelium without dysplasia. In preoperative punch biopsies from patients with long-standing ulcerative colitis, the presence of structures compatible with villous adenoma--even those without cellular dysplasia--should be considered an ominous histologic sign and, thus, an indication for panproctocolectomy.

Non-dysplastic villous changes in endoscopic biopsies in ulcerative colitis with carcinoma

Three cases of long-standing ulcerative colitis and invasive adenocarcinoma are described. In all three cases, pre-operative rectal and/or colonoscopic biopsies demonstrated the presence of a villous adenoma: two without dysplasia and the third with moderate dysplasia. The presence of structures compatible with villous adenoma should be, even in the absence of epithelial dysplasia, an indication for panproctocolectomy in patients with long-standing ulcerative colitis.