A long hard look at Dukes' B

Transition to quantitative faecal immunochemical testing from guaiac faecal occult blood testing in a fully rolled-out population-based national bowel screening programme

OBJECTIVE

Faecal immunochemical tests (FIT) are replacing guaiac faecal occult blood tests (FOBT) in colorectal cancer (CRC) screening. Data from the first year of FIT screening were compared with those from FOBT screening and assumptions based on a pilot evaluation of FIT.

DESIGN

Data on uptake, positivity, positive predictive value (PPV) for CRC and higher-risk adenoma from participants in the first year of the FIT-based Scottish Bowel Screening Programme (n=919 665), with a threshold of 80 µg Hb/g faeces, were compared with those from the penultimate year of the FOBT-based programme (n=862 165) and those from the FIT evaluation (n=66 225).

RESULTS

Overall, uptake of FIT was 63.9% compared with 56.4% for FOBT. Positivity was 3.1% and 2.2% with FIT and FOBT; increases were seen in both sexes, and across age range and deprivation. More CRC and adenomas were detected by FIT, but the PPV for CRC was less (5.2% with FIT and 6.4% with FOBT). However, for higher-risk adenoma, PPV was greater with FIT (24.3% with FIT and 19.3% with FOBT). In the previous FIT evaluation, uptake was 58.5% with FIT compared with 54.0% with FOBT; positivity was 2.5% with FIT and 2.0% with FOBT.

CONCLUSION

Transition to FIT from FOBT produced higher uptake and positivity with lower PPV for CRC and higher PPV for adenoma. The FIT pilot evaluation underestimated uptake and positivity. Introducing FIT at the same threshold as the evaluation caused a 67.2% increase in colonoscopy demand instead of a predicted 10%.

Faecal immunochemical tests (FIT) versus colonoscopy for surveillance after screening and polypectomy: a diagnostic accuracy and cost-effectiveness study

OBJECTIVE

The English Bowel Cancer Screening Programme (BCSP) recommends 3 yearly colonoscopy surveillance for patients at intermediate risk of colorectal cancer (CRC) postpolypectomy (those with three to four small adenomas or one ≥10 mm). We investigated whether faecal immunochemical tests (FITs) could reduce surveillance burden on patients and endoscopy services.

DESIGN

Intermediate-risk patients (60-72 years) recommended 3 yearly surveillance were recruited within the BCSP (January 2012-December 2013). FITs were offered at 1, 2 and 3 years postpolypectomy. Invitees consenting and returning a year 1 FIT were included. Participants testing positive (haemoglobin ≥40 µg/g) at years one or two were offered colonoscopy early; all others were offered colonoscopy at 3 years. Diagnostic accuracy for CRC and advanced adenomas (AAs) was estimated considering multiple tests and thresholds. We calculated incremental costs per additional AA and CRC detected by colonoscopy versus FIT surveillance.

RESULTS

74% (5938/8009) of invitees were included in our study having participated at year 1. Of these, 97% returned FITs at years 2 and 3. Three-year cumulative positivity was 13% at the 40 µg/g haemoglobin threshold and 29% at 10 µg/g. 29 participants were diagnosed with CRC and 446 with AAs. Three-year programme sensitivities for CRC and AAs were, respectively, 59% and 33% at 40 µg/g, and 72% and 57% at 10 µg/g. Incremental costs per additional AA and CRC detected by colonoscopy versus FIT (40 µg/g) surveillance were £7354 and £180 778, respectively.

CONCLUSIONS

Replacing 3 yearly colonoscopy surveillance in intermediate-risk patients with annual FIT could reduce colonoscopies by 71%, significantly cut costs but could miss 30%-40% of CRCs and 40%-70% of AAs.

TRIAL REGISTRATION NUMBER

ISRCTN18040196; Results.

Consecutive negative findings on colonoscopy during surveillance predict a low risk of advanced neoplasia in patients with inflammatory bowel disease with long-standing colitis: results of a 15-year multicentre, multinational cohort study

OBJECTIVES

Surveillance colonoscopy is thought to prevent colorectal cancer (CRC) in patients with long-standing colonic IBD, but data regarding the frequency of surveillance and the findings thereof are lacking. Our aim was to determine whether consecutive negative surveillance colonoscopies adequately predict low neoplastic risk.

DESIGN

A multicentre, multinational database of patients with long-standing IBD colitis without high-risk features and undergoing regular CRC surveillance was constructed. A 'negative' surveillance colonoscopy was predefined as a technically adequate procedure having no postinflammatory polyps, no strictures, no endoscopic disease activity and no evidence of neoplasia; a 'positive' colonoscopy was a technically adequate procedure that included at least one of these criteria. The primary endpoint was advanced colorectal neoplasia (aCRN), defined as high-grade dysplasia or CRC.

RESULTS

Of 775 patients with long-standing IBD colitis, 44% (n=340) had >1 negative colonoscopy. Patients with consecutive negative surveillance colonoscopies were compared with those who had at least one positive colonoscopy. Both groups had similar demographics, disease-related characteristics, number of surveillance colonoscopies and time intervals between colonoscopies. No aCRN occurred in those with consecutive negative surveillance, compared with an incidence rate of 0.29 to 0.76/100 patient-years (P=0.02) in those having >1 positive colonoscopy on follow-up of 6.1 (P25-P75: 4.6-8.2) years after the index procedure.

CONCLUSION

Within this large surveillance cohort of patients with colonic IBD and no additional high-risk features, having two consecutive negative colonoscopies predicted a very low risk of aCRN occurrence on follow-up. Our findings suggest that longer surveillance intervals in this selected population may be safe.

Improved adenoma detection with Endocuff Vision: the ADENOMA randomised controlled trial

OBJECTIVE

Low adenoma detection rates (ADR) are linked to increased postcolonoscopy colorectal cancer rates and reduced cancer survival. Devices to enhance mucosal visualisation such as Endocuff Vision (EV) may improve ADR. This multicentre randomised controlled trial compared ADR between EV-assisted colonoscopy (EAC) and standard colonoscopy (SC).

DESIGN

Patients referred because of symptoms, surveillance or following a positive faecal occult blood test (FOBt) as part of the Bowel Cancer Screening Programme were recruited from seven hospitals. ADR, mean adenomas per procedure, size and location of adenomas, sessile serrated polyps, EV removal rate, caecal intubation rate, procedural time, patient experience, effect of EV on workload and adverse events were measured.

RESULTS

1772 patients (57% male, mean age 62 years) were recruited over 16 months with 45% recruited through screening. EAC increased ADR globally from 36.2% to 40.9% (P=0.02). The increase was driven by a 10.8% increase in FOBt-positive screening patients (50.9% SC vs 61.7% EAC, P<0.001). EV patients had higher detection of mean adenomas per procedure, sessile serrated polyps, left-sided, diminutive, small adenomas and cancers (cancer 4.1% vs 2.3%, P=0.02). EV removal rate was 4.1%. Median intubation was a minute quicker with EAC (P=0.001), with no difference in caecal intubation rate or withdrawal time. EAC was well tolerated but caused a minor increase in discomfort on anal intubation in patients undergoing colonoscopy with no or minimal sedation. There were no significant EV adverse events.

CONCLUSION

EV significantly improved ADR in bowel cancer screening patients and should be used to improve colonoscopic detection.

TRIAL REGISTRATION NUMBER

NCT02552017, Results; ISRCTN11821044, Results.

Faecal haemoglobin concentration is related to severity of colorectal neoplasia

AIMS

Guaiac faecal occult blood tests are being replaced by faecal immunochemical tests (FIT). We investigated whether faecal haemoglobin concentration (f-Hb) was related to stage in progression of colorectal neoplasia, studying cancer and adenoma characteristics in an evaluation of quantitative FIT as a first-line screening test.

METHODS

We invited 66 225 individuals aged 50-74 years to provide one sample of faeces. f-Hb was measured on samples from 38 720 responders. Colonoscopy findings and pathology data were collected on the 943 with f-Hb ≥ 400 ng Hb/ml (80 µg Hb/g faeces).

RESULTS

Of the 814 participants with outcome data (median age: 63 years, range 50-75, 56.4% male), 39 had cancer, 190 high-risk adenoma (HRA, defined as ≥ 3 or any ≥ 10 mm) and 119 low-risk adenoma (LRA). 74.4% of those with cancer had f-Hb>1000 ng Hb/ml compared with 58.4% with HRA, and 44.1% with no pathology. Median f-Hb concentration was higher in those with cancer than those with no (p<0.002) or non-neoplastic (p<0.002) pathology, and those with LRA (p=0.0001). Polyp cancers had lower concentrations than more advanced stage cancers (p<0.04). Higher f-Hb was also found in those with HRA than with LRA (p<0.006), large (>10 mm) compared with small adenoma (p<0.0001), and also an adenoma displaying high-grade dysplasia compared with low-grade dysplasia (p<0.009).

CONCLUSIONS

f-Hb is related to severity of colorectal neoplastic disease. This has ramifications for the selection of the appropriate cut-off concentration adopted for bowel screening programmes.

HIPEC in T4a colon cancer: a defendable treatment to improve oncologic outcome?

BACKGROUND

Adequate estimation of the potential benefits of 'adjuvant' hyperthermia and intraperitoneal chemotherapy (HIPEC) in T4 patients through assessment of the burden of peritoneal carcinomatosis (PC) in T4 tumors and the risk of PC as the only metastatic site.

PATIENTS AND METHODS

Analysis of prospectively collected data on patients who underwent surgery for colon cancer (Jan 2004-Jan 2007).

RESULTS

About 379 patients (M/F = 204/175) were included, with a median age of 71.8 years (range 35.4-95.0): 39 stage I, 126 stage II, 89 stage III, 116 stage IV disease (+9 with unknown stage). The median follow-up was 34.8months [range 0.0-79.4]. The 3- and 5-year overall survival rates (OS) were 68.4% (95% confidence interval (CI) 63.9%-72.4%) and 60.3% (95%CI 55.6%-64.7%). Relapse analysis was restricted to stages II-III T3 (N = 154) and T4 tumors (N = 19) with complete relapse data, of which 13.2% developed PC. PC has a detrimental effect on OS [HR 6.3 (95%CI: 3.1-13.0, P < 0.0001)]. 50% of T4a and 20% of T4b developed PC. The 1- and 3-year PC percentage was significantly lower for T3 (4.5% and 9.3%) than T4 tumors (15.6% and 36.7%) (P = 0.008). PC was the only metastatic site in 3/15 T3 [proportion 0.20, 95%CI (0.043-0.481)] and 5/8 T4 tumors with PC [proportion 0.625, 95%CI (0.245-0.915)] (P = 0.071).

CONCLUSIONS

T4a colon tumors have a significantly higher risk of developing PC. Twenty-five percent (5/19) of stages II-III T4 tumors develop PC as the only metastatic site. This could define the possible window of opportunity for adjuvant HIPEC to prevent PC.

Identification of serosal invasion and extramural venous invasion on review of Dukes' stage B colonic carcinomas and correlation with survival

AIMS

To determine whether serosal invasion (SI) and/or extramural venous invasion (VI) could be more frequently identified on review of Dukes' stage B colonic carcinoma resection specimens and whether the revised findings correlated with clinical outcome.

METHODS AND RESULTS

The original histology slides from 82 patients with Dukes' stage B colonic carcinoma were reviewed specifically to identify tumours showing SI and/or VI. All tumours were initially reported to be negative for both pathological parameters. The selected cases included 35 patients who died of carcinoma within 5 years of surgery and 47 patients with a minimum of 5-years' postoperative survival. The review was blinded to the original histopathology reports and to clinical follow-up data. SI and/or VI were identified in 26 cases (32%). Fourteen of 18 patients with SI, 8/12 patients with VI and all four patients with both adverse histological features died of carcinoma.

CONCLUSIONS

Review of routinely sampled and stained colonic carcinoma resection specimens increased the proportion of cases classified as positive for SI and/or VI. The revised assessment correlated with patient outcome. Reliable identification of these features may permit stratification of high-risk patients with Dukes' stage B colonic cancer who could benefit from adjuvant treatment.

Mobile colonoscopic surveillance provides quality care for hereditary nonpolyposis colorectal carcinoma families in South Africa

BACKGROUND

It is difficult to provide a colonoscopic surveillance service for at-risk family members with hereditary nonpolyposis colorectal carcinoma when many of those family members live in a remote area of South African far from endoscopic services. A mobile surveillance programme was established to service these individuals.

OBJECTIVE

The aim of this study was to compare the quality of the mobile service to that provided in established endoscopy units.

METHOD

Ninety-one asymptomatic subjects with known disease-causing mutations underwent 259 colonoscopies. Of these, 171 colonoscopies were performed by a mobile colonoscopy service in small rural hospitals and 88 in established endoscopy units. The quality of the colonoscopic services was measured by completion rate, the rate of detection of colonoscopic abnormalities, histopathological analyses of biopsies, surgical intervention and colorectal cancer deaths.

RESULTS

The caecum was reached in 96% of all colonoscopies. A significant lesion was detected in 8.8% of colonoscopies. There was no difference in the rate of complete colonoscopy and detection rate of lesions in the established units and the mobile service (both P = 0.6). The rate of detection of early adenocarcinomas was similar (P = 0.17). The colonoscopic screening/surveillance programme meets international standards with a high accuracy (95.75%) and negative predictive value (100%).

CONCLUSION

The mobile service provides access to colonoscopy in remote areas without compromising the quality of service.

Vagal modulation of intestinal afferent sensitivity to systemic LPS in the rat

The central nervous system modulates inflammation in the gastrointestinal tract via efferent vagal pathways. We hypothesized that these vagal efferents receive synaptic input from vagal afferents, representing an autonomic feedback mechanism. The consequence of this vagovagal reflex for afferent signal generation in response to LPS was examined in the present study. Different modifications of the vagal innervation or sham procedures were performed in anesthetized rats. Extracellular mesenteric afferent nerve discharge and systemic blood pressure were recorded in vivo before and after systemic administration of LPS (6 mg/kg iv). Mesenteric afferent nerve discharge increased dramatically following LPS, which was unchanged when vagal efferent traffic was eliminated by acute vagotomy. In chronically vagotomized animals, to eliminate both vagal afferent and efferent traffic, the increase in afferent firing 3.5 min after LPS was reduced to 3.2 +/- 2.5 impulses/s above baseline compared with 42.2 +/- 2.0 impulses/s in controls (P < 0.001). A similar effect was observed following perivagal capsaicin, which was used to eliminate vagal afferent traffic only. LPS also caused a transient hypotension (<10 min), a partial recovery, and then persistent hypertension that was exacerbated by all three procedures. Mechanosensitivity was increased 15 min following LPS but had recovered at 30 min in all subgroups except for the chronic vagotomy group. In conclusion, discharge in capsaicin-sensitive mesenteric vagal afferents is augmented following systemic LPS. This activity, through a vagovagal pathway, helps to attenuate the effects of septic shock. The persistent hypersensitivity to mechanical stimulation after chronic vagal denervation suggests that the vagus exerts a regulatory influence on spinal afferent sensitization following LPS.

Follow up of patients with colorectal polyps: are the BSG guidelines being adhered to?

OBJECTIVE

The publication of the BSG guidelines in 2002 provided a framework for the follow up of patients with colorectal polyps. The aim of the present study was to determine whether they had, or were being correctly adhered to in a moderately sized District General Hospital.

METHOD

A total of 598 patients were on the waiting list for colonoscopy at Airedale General Hospital (AGH) in February 2005. Of these, 203 were being followed up as a result of the previous finding of a polyp.

RESULTS

Only 14.8% of patients had been or were being followed up according to the BSG guidelines. The majority of the 85.2% of patients who did not comply with follow up did so as a result of over investigation. Seventy-eight per cent of the low-risk group and 55% of the intermediate-risk group had been colonoscoped, or were waiting to have colonoscopy, too soon or too frequently according to the BSG guidelines. Twenty-four patients with hyperplastic polyps were being followed up incorrectly, as were 17 patients discovered to have a polyp pathology on flexible sigmoidoscopy. It was established that 131 extra colonoscopies had been, or were planned to be performed unnecessarily.

CONCLUSION

These data have major implications with regard to patient safety, service provision and cost to the NHS.

Molecular, functional, and pharmacological targets for the development of gut promotility drugs

The science of gastrointestinal motility has made phenomenal advances during the last fifty years. Yet, there is a paucity of effective promotility drugs to treat functional bowel disorders that affect 10-29% of the U.S. population. A part of the reason for the lack of effective drugs is our limited understanding of the etiology of these diseases. In the absence of this information, mostly an ad hoc approach has been used to develop the currently available drugs, which are modestly effective or effective in only a subset of the patients with functional bowel disorders. This review discusses a grounds-up approach for development of the next generation of promotility drugs. The approach is based on our current understanding of 1) the different types of contractions that produce overall motility function of mixing and orderly net distal propulsion in major gut organs, 2) the regulatory mechanisms of these contractions, 3) which receptors and intracellular signaling molecules could be targeted to stimulate specific types of contractions to accelerate or retard transit, and 4) the strengths and limitations of animal models and experimental approaches that could screen potential promotility drugs for their efficacy in human gut propulsion in functional bowel disorders.

Polyp measurement using CT colonography: agreement with colonoscopy and effect of viewing conditions on interobserver and intraobserver agreement

OBJECTIVE

This article presents inter- and intraobserver agreement for estimates of polyp diameter using CT colonography, including the effects of different visualization displays and prior experience.

MATERIALS AND METHODS

Four observers, three of whom had prior experience with CT colonography, estimated the maximum diameter of 48 polyps using three different visualization displays: 2D colonography window, 2D abdominal window, and 3D surface rendering. Each re-measured a subset of 10 polyps. Polyps measured 2 to 12 mm according to a colonoscopic reference. Inter- and intraobserver agreement and agreement with the reference measurement were determined using the Bland-Altman method, paired Student's t testing, analysis of variance, and analysis of covariance (ANCOVA), and by calculating the components of variance.

RESULTS

CT measurements overestimated polyp diameter, a phenomenon found least using the 2D abdominal display. Generally, 95% limits of agreement encompassed different size categories for individual polyps: the widest spanned 14.6 mm (-4.6 mm to 10.0 mm) for an experienced observer using the 3D display. When using the 2D abdominal display, no significant difference was found between estimates and the reference value for the other two experienced observers (p = 0.83 and 0.23). All the observers' measurements were significantly different from the reference when using the 3D display (p < 0.001). The novice was significantly different from the experienced observers in some analyses. Inter- and intraobserver agreement were poorest for the 3D display.

CONCLUSION

Measurement of polyp diameter from CT colonography is subject to variation contingent on the observer's experience and the viewing display used. Although 3D visualization display is commonly used for polyp detection, it should not be used for measurement.

Review article: Population screening for colorectal cancer

Colorectal cancer is a common cancer and common cause of death. The mortality rate from colorectal cancer can be reduced by identification and removal of cancer precursors, adenomas, or by detection of cancer at an earlier stage. Pilot screening programmes have demonstrated decreased colorectal cancer mortality; as a result many countries are developing colorectal cancer screening programmes. The most common modalities being evaluated are faecal occult blood testing, flexible sigmoidoscopy and colonoscopy. Implementation of screening tests has been hampered by cost, invasiveness, availability of resources and patient acceptance. New technologies such at computed tomographic colonography and stool screening for molecular markers of neoplasia are in development as potential minimally invasive tools. This review considers who should be screened, which test to use and how often to screen.

Tumour budding as prognostic factor in stage I/II colorectal carcinoma

AIMS

The term tumour 'budding' has been coined for the detachment of tumour cells from the neoplastic glands of adenocarcinomas and is presumed to be an early step in the metastatic process. A limited number of studies have shown budding to be an adverse prognostic factor.

METHODS AND RESULTS

All primary single, non-metachronous TNM stage I/II colorectal carcinomas without neoadjuvant treatment resected in the years 1994-1999 were included (n = 186). Tumour buds were counted in pan-cytokeratin immunostains in a 0.785-mm2 field of vision (250 x). During follow-up 21 patients had distant metastases and 12 patients died of their disease. Budding was determined at 14 and 20.46, median and mean, respectively (range 0-120). A cut-off of 25 was found to be sensitive (0.76) and specific (0.739). Kaplan-Meier survival analysis showed high budding to be a strong adverse prognosticator. By Cox regression, high budding together with venous angioinvasion were independent prognostic factors.

CONCLUSIONS

This study confirms the prognostic value of budding in a contemporary series of colorectal carcinomas that by TNM were low risk. Technically easy, rapid and robust to determine, budding quantified in pan-cytokeratin stains significantly aids in the identification of high-risk patients and is recommended for more general use in surgical pathology.

Slowing of intestinal transit by fat or peptide YY depends on beta-adrenergic pathway

Although the enteric reflex pathway triggered by volume distension is known to depend on an adrenergic nerve, it is not known whether the slowing of intestinal transit by fat or peptide YY (PYY) also depends on an adrenergic pathway. The aim of this study was to test the hypotheses that the slowing of transit by fat or PYY may depend on a beta-adrenergic pathway, and this adrenergic pathway may act via the serotonergic and opioid pathways previously observed for the slowing of transit by fat. Eighteen dogs were equipped with duodenal and midgut fistulas. The small intestine was compartmentalized into the proximal and distal half of gut. The role of adrenergic, serotonergic, and opioid pathways was then tested in the slowing of intestinal transit by fat, PYY, and norepinephrine. Intestinal transit results were compared as the cumulative percent marker of recovery over 30 min. We found that the slowing of transit by fat, PYY, or norepinephrine was reversed by propranolol. In addition, the slowing effect of fat was reversed by metoprolol (beta1-adrenoreceptor antagonist) but not phentolamine (alpha-adrenoreceptor antagonist). Furthermore, norepinephrine-induced slowing of transit was reversed by ondansetron (5-HT3 receptor antagonist) or naloxone (opioid receptor antagonist). Extending these physiological results, we also found by immunohistochemistry that beta1-adrenoreceptors are expressed by neurons of the intrinsic plexuses of the small intestine. We conclude that the slowing of intestinal transit by fat or PYY depends on a beta-adrenergic pathway and that this adrenergic pathway acts on serotonergic and opioid pathways.

Morphological characteristics and immunohistochemical detection of nicotinic acetylcholine receptors on intestinofugal afferent neurones in guinea-pig colon

Intestinofugal afferent neurones (IFANs) provide excitatory synaptic input to abdominal prevertebral ganglion neurones. Input is greatly reduced during blockade of nicotinic acetylcholine receptors (nAChRs) in the wall of the colon, suggesting two projection pathways: a direct pathway without synaptic interruption and an indirect pathway interrupted by at least one nicotinic cholinergic synapse. This study aimed to characterize the morphology of IFANs and examine the distribution of nAChRs on them. We identified IFANs in guinea-pig colon by retrograde labelling with fluorescent tracer DiI placed either on the lumbar colonic nerves in vitro or inferior mesenteric ganglion in vivo. Confocal laser scanning microscopy and computerized image-processing software were used for 3D image reconstruction. Approximately 70% of identified IFANs had Dogiel type I-like morphology, the remainder were Dogiel type II-like. In vivo labelled IFANs were injected with Lucifer Yellow and immunostained for nAChRs using monoclonal antibody MAb35. Approximately 3% of total plasma membrane surface of IFANs with Dogiel type I morphology had MAb35-IR. In contrast, <1% of membrane surface of IFANs with Dogiel type II morphology had MAb35-IR. The finding that IFANs displayed immunostaining for nAChRs suggests the presence of putative nicotinic synapses.