Management of complex colonic polyps in the English Bowel Cancer Screening Programme

BACKGROUND

Large sessile or flat colonic polyps, defined as polyps at least 20  mm in size, are difficult to treat endoscopically and may harbour malignancy. The aim of this study was to describe their current management to provide insight into optimal management.

METHODS

This retrospective observational study identified patients with large sessile or flat polyps detected in the English Bowel Cancer Screening Programme between 2006 and 2009. Initial therapeutic modality (surgical or endoscopic), subsequent management and outcomes were recorded. The main outcome measures analysed were: presence of malignancy, need for surgical treatment, complications, and residual or recurrent polyp at 12 months.

RESULTS

In total, 557 large sessile or flat polyps with benign appearance or initial histology were identified in 557 patients. Some 436 (78.3 per cent) were initially managed endoscopically and 121 (21.7 per cent) were managed surgically from the outset. Seventy of those initially treated endoscopically subsequently required surgery owing to the presence of malignancy (19) or not being suitable for further endoscopic management (51). Residual or recurrent polyp was present at 12 months in 26 (6.0 per cent) of 436 patients managed endoscopically. There was wide variation between centres in the use of surgery as a primary therapy, ranging from 7 to 36 per cent. Endoscopic complications included bleeding in 13 patients (3.0 per cent) and perforation in two (0.5 per cent).

CONCLUSION

Management of large sessile or flat colonic polyps is safe and effective in the English Bowel Cancer Screening Programme. Wide variation in the use of surgery suggests a need for standardized management algorithms. Presented to a meeting of the British Society of Gastroenterology, Birmingham, U.K., March 2011.

Outcome of 12-month surveillance colonoscopy in high-risk patients in the National Health Service Bowel Cancer Screening Programme

AIM

Current British guidelines recommend surveillance colonoscopy at 12 months for individuals found to have five or more adenomas, or three or more adenomas of which at least one is ≥ 1 cm in size. This study describes the yield of surveillance colonoscopy in this group and explores patient and clinical factors that may be associated with the presence of advanced adenomas or cancer at surveillance.

METHOD

Data were retrieved from the national database of the National Health Service Bowel Cancer Screening Programme. The detection of advanced colonic neoplasia (ACN, cancer or advanced adenoma) was used as the main outcome variable. Multivariable analysis was used to analyse relationships between patient factors (age, gender, body mass index, smoking and alcohol use) and clinical findings (number, size and nature of adenomas detected during index colonoscopy) with the outcome variable.

RESULTS

One-thousand, seven-hundred and sixty individuals were included in the study. The yield of ACN at 12-month surveillance was 6.6% (116/1760), of which 14/1760 (0.8%) had colorectal cancer. Nine (64.3%) of these 14 cancers were Dukes A at diagnosis. The presence of a villous adenoma or a right-sided adenoma at screening colonoscopy was associated with ORs of 1.98 (95% CI: 1.11-3.53, P = 0.012) and 1.76 (95% CI: 1.13-2.74, P = 0.020), respectively, for detection of ACN at surveillance.

CONCLUSION

Twelve-month surveillance colonoscopy is necessary in this group of patients. The presence of villous or proximal lesions at baseline is associated with increased risk of ACN at surveillance. Site and histological type of baseline lesions may be relevant for determining the surveillance interval.

Longer mean colonoscopy withdrawal time is associated with increased adenoma detection: evidence from the Bowel Cancer Screening Programme in England

BACKGROUND AND STUDY AIMS

Increasing colonoscopy withdrawal time (CWT) is thought to be associated with increasing adenoma detection rate (ADR). Current English guidelines recommend a minimum CWT of 6 minutes. It is known that in the Bowel Cancer Screening Programme (BCSP) in England there is wide variation in CWT. The aim of this observational study was to examine the relationship between CWT and ADR.

PATIENTS AND METHODS

The study examined data from 31 088 colonoscopies by 147 screening program colonoscopists. Colonoscopists were grouped in four levels of mean CWT ( < 7, 7 - 8.9, 9 - 10.9, and ≥ 11 minutes). Univariable and multivariable analysis (binary logistic and negative binomial regression) were used to explore the relationship between CWT, ADR, mean number of adenomas and number of right-sided and advanced adenomas.

RESULTS

In colonoscopists with a mean CWT < 7 minutes, the mean ADR was 42.5 % compared with 47.1 % in the ≥ 11-minute group (P < 0.001). The mean number of adenomas detected per procedure increased from 0.77 to 0.94, respectively (P < 0.001). The increase in adenoma detection was mainly of subcentimeter or proximal adenomas; there was no increase in the detection of advanced adenomas. Regression models showed an increase in ADR from 43 % to 46.5 % for mean CWT times ranging from 6 to 10 minutes.

CONCLUSIONS

This study demonstrates that longer mean withdrawal times are associated with increasing adenoma detection, mainly of small or right-sided adenomas. However, beyond 10 minutes the increase in ADR is minimal. Mean withdrawal times longer than 6 minutes are not associated with increased detection of advanced adenomas. Withdrawal time remains an important quality metric of colonoscopy.

CT colonography in the English Bowel Cancer Screening Programme: national survey of current practice

AIM

To obtain information regarding the provision of computed tomography colonography (CTC) services to the National Health Service (NHS) Bowel Cancer Screening Programme (BCSP).

MATERIALS AND METHODS

Specialist screening practitioners at the 58 BCSP screening centres and lead BCSP radiologists at 110 hospitals performing CTC for the Programme were contacted and completed a semi-structured questionnaire administered by telephone. Responses were collated and descriptive statistics derived.

RESULTS

One hundred and seven (98%) SSPs and 103 (94%) radiologists were surveyed. All screening centres had access to CTC at 110 hospital sites. All sites used CTC for failed or contraindicated colonoscopy, 24% used it for patients taking anticoagulants, and 17% for those with fear of colonoscopy. Patient preference was not an indication at any site. Multidetector CT (100%), carbon dioxide insufflators (94%), and CTC software (95%) were almost universal. Ninety-one percent of radiographers and 98% of radiologists were trained in CTC image acquisition and interpretation, respectively. Seventy-five percent of the radiologists were gastrointestinal subspecialists and two-thirds had interpreted more than 300 examinations in clinical practice, although 5% had interpreted fewer than 100. Eighty-one percent of radiologists favoured some form of accreditation for CTC interpretation.

CONCLUSIONS

CTC is widely available to the BCSP. Appropriate hardware and software is almost ubiquitous. Most radiographers and radiologists offering CTC to the BCSP have received specific training. Formal service evaluation is patchy. The majority of radiologists would welcome national accreditation for CTC.

A retrospective observational study examining the characteristics and outcomes of tumours diagnosed within and without of the English NHS Bowel Cancer Screening Programme

Background:

Colorectal cancer is common in England and, with long-term survival relatively poor, improving outcomes is a priority. A major initiative to reduce mortality from the disease has been the introduction of the National Health Service (NHS) Bowel Cancer Screening Programme (BCSP). Combining data from the BCSP with that in the National Cancer Data Repository (NCDR) allows all tumours diagnosed in England to be categorised according to their involvement with the BCSP. This study sought to quantify the characteristics of the tumours diagnosed within and outside the BCSP and investigate its impact on outcomes.

Methods:

Linkage of the NCDR and BCSP data allowed all tumours diagnosed between July 2006 and December 2008 to be categorised into four groups; screen-detected tumours, screening-interval tumours, tumours diagnosed in non-participating invitees and tumours diagnosed in those never invited to participate. The characteristics, management and outcome of tumours in each category were compared.

Results:

In all, 76 943 individuals were diagnosed with their first primary colorectal cancer during the study period. Of these 2213 (2.9%) were screen-detected, 623 (0.8%) were screening-interval cancers, 1760 (2.3%) were diagnosed in individuals in non-participating invitees and 72 437 (94.1%) were diagnosed in individuals not invited to participate in the programme due to its ongoing roll-out over the time period studied. Screen-detected tumours were identified at earlier Dukes’ stages, were more likely to be managed with curative intent and had significantly better outcomes than tumours in other categories.

Conclusion:

Screen-detected cancers had a significantly better prognosis than other tumours and this would suggest that the BCSP should reduce mortality from colorectal cancer in England.

Detection and Confirmation of Ractopamine and Its Metabolites in Horse Urine After Paylean® Administration*

We have investigated the detection, confirmation, and metabolism of the beta-adrenergic agonist ractopamine administered as Paylean to the horse. A Testing Components Corporation enzyme-linked imunosorbent assay (ELISA) kit for ractopamine displayed linear response between 1.0 and 100 ng/mL with an I-50 of 10 ng/mL and an effective screening limit of detection of 50 ng/mL. The kit was readily able to detect ractopamine equivalents in unhydrolyzed urine up to 24 h following a 300-mg oral dose. Gas chromatography-mass spectrometry (GC-MS) confirmation comprised glucuronidase treatment, solid-phase extraction, and trimethylsilyl derivatization, with selected-ion monitoring of ractopamine-tris(trimethylsilane) (TMS) m/z 267, 250, 179, and 502 ions. Quantitation was elaborated in comparison to a 445 Mw isoxsuprine-bis(TMS) internal standard monitored simultaneously. The instrumental limit of detection, defined as that number of ng on column for which signal-to-noise ratios for one or more diagnostic ions fell below a value of three, was 0.1 ng, corresponding to roughly 5 ng/mL in matrix. Based on the quantitation ions for ractopamine standards extracted from urine, standard curves showed a linear response for ractopamine concentrations between 10 and 100 ng/mL with a correlation coefficient r > 0.99, whereas standards in the concentration range of 10-1000 ng/mL were fit to a second-order regression curve with r > 0.99. The lower limit of detection for ractopamine in urine, defined as the lowest concentration at which the identity of ractopamine could be confirmed by comparison of diagnostic MS ion ratios, ranged between 25 and 50 ng/mL. Urine concentration of parent ractopamine 24 h post-dose was measured at 360 ng/mL by GC-MS after oral administration of 300 mg. Urinary metabolites were identified by electrospray ionization (+) tandem quadrupole mass spectrometry and were shown to include glucuronide, methyl, and mixed methyl-glucuronide conjugates. We also considered the possibility that an unusual conjugate added 113 amu to give an observed m/z 415 [M+H] species or two times 113 amu to give an m/z 528 [M+H] species with a daughter ion mass spectrum related to the previous one. Sulfate and mixed methyl-sulfate conjugates were revealed following glucuronidase treatment, suggesting that sulfation occurs in combination with glucuronidation. We noted a paired chromatographic peak phenomenon of apparent ractopamine metabolites appearing as doublets of equivalent intensity with nearly identical mass spectra on GC-MS and concluded that this phenomenon is consistent with Paylean being a mixture of RR, RS, SR, and SS diastereomers of ractopamine. The results suggest that ELISA-based screening followed by glucuronide hydrolysis, parent drug recovery, and TMS derivatization provide an effective pathway for detection and GC-MS confirmation of ractopamine in equine urine.

Purification of molecularly bridged metal nanoparticle arrays by centrifugation and size exclusion chromatography

Size exclusion chromatography and centrifugation separation protocols were developed and compared for isolating enriched fractions of phenylethynyl-bridged metal nanoparticle dimers and trimers from the monomeric particle starting material. Both methods enabled the isolation of enriched fractions of a desired array without causing significant sample aggregation or replacement of the phenylethynyl bridge. Solutions containing ca. 70% bridged gold dimers were obtained using either method. The further development of methods for separating discrete arrays of covalently bridged nanoparticle homo and hetero structures is expected to help advance our understanding of collective metal particle electronic structure-function relationships.

A methodology for choosing a physician profiling system: the case of First Option Health Plan

The public continues to demand improved health care at affordable costs. It appears that this public pressure will force health maintenance organizations (HMOs) and other health care providers to face their toughest days in the years to come. They will need to find solutions to resolve this "quality and cost" problem. One method that is likely to have the ability to improve quality of care and control costs is physician profiling. That is, data related to a physician's care or outcomes can be collected and compared with profiles of various populations, for example, other similar providers in a relatively close geographical proximity. This article examines the issues involved in physician profiling, including the characteristics of profiling systems and the direct and indirect benefits of having such a system. Further, the article uses an actual HMO example to discuss considerations that administrators should make when choosing a physician profiling system.

Molecular cytogenetic analysis of patients with holoprosencephaly and structural rearrangements of 7q

The holoprosencephaly (HPE) sequence is a malformation complex with abnormal midline cleavage of the embryonic forebrain. HPE is genetically heterogeneous with at least 6 different chromosome regions containing genes involved in the expression of the phenotype. HPE3, recently identified as the human Sonic hedgehog gene, is localized to 7q36. We have used fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) amplification in 5 cell lines from patients with HPE (3 cases), HPE and sacral agenesis (1 case), and microcephaly (1 case) to further define the structural rearrangements of the long arm of chromosome 7 in each case. All cell lines demonstrated loss of material in the critical region of HPE3 at band 7q36, which includes the Sonic hedgehog gene. We report here the analysis of these patient cell lines.

Trandolapril inhibits atherosclerosis in the Watanabe heritable hyperlipidemic rabbit

The effects of trandolapril (0.25 mg/kg body wt per 48 hours) on aortic atherosclerosis were examined in the Watanabe heritable hyperlipidemic rabbit treated from 3 to 12 months of age. Trandolapril caused a significant decrease in atherosclerotic involvement of the intimal surface of total aorta from 56.3 +/- 5.0% in control Watanabe rabbits to 35.0 +/- 4.1% with treatment (p less than 0.01). The largest reductions were observed in descending thoracic aorta where 21.8 +/- 5.7% of intimal surface was involved in the trandolapril-treated animals versus 54.4 +/- 7.7% in the control group (p less than 0.01). Significant decreases also occurred in ascending aorta/arch and abdominal aortic segments. Cholesterol content of descending thoracic aorta was also significantly reduced in the trandolapril-treated rabbits. The atherosclerotic plaques in aorta from trandolapril-treated rabbits appeared to contain less foam cells and relatively greater amounts of connective tissue than those from control animals. These studies indicate that trandolapril inhibits aortic atherosclerosis in the Watanabe heritable hyperlipidemic rabbit. The similarity in results between the current study and that using captopril suggests that the antiatherosclerotic action of trandolapril and captopril represents a class effect related to angiotensin converting enzyme inhibition.

Expression of human HLA-B27 transgene alters susceptibility to murine Theiler's virus-induced demyelination

Infection of certain strains of mice with Theiler's murine encephalomyelitis virus results in persistence of virus and an immune-mediated primary demyelination in the central nervous system that resembles multiple sclerosis. Because susceptibility/resistance to demyelination in B10 congeneic mice maps strongly to class I MHC genes (D region) we tested whether expression of a human class I MHC gene (HLA-B27) would alter susceptibility to Theiler's murine encephalomyelitis virus-induced demyelination. Transgenic HLA-B27 mice were found to co-express human and endogenous mouse class I MHC genes by flow microfluorimetry analysis of PBL. In the absence of the human transgene, H-2stf, or v mice but not H-2b mice had chronic demyelination and persistence of virus at 45 days after infection. No difference in degree of demyelination, meningeal inflammation, or virus persistence was seen between transgenic HLA-B27 and nontransgenic littermate mice of H-2f or H-2v haplotype. In contrast, H-2s (HLA-B27+) mice showed a dramatic decrease in extent of demyelination and number of virus-Ag+ cells in the spinal cord compared with H-2s (HLA-B27-) littermate mice. In addition, none of the eight H-2s mice homozygous for HLA-B27 gene had spinal cord lesions even though infectious virus was isolated chronically from their central nervous system. Expression of HLA-B27 transgene did not interfere with the resistance to demyelination normally observed in B10 (H-2b) mice. These experiments demonstrate that expression of a human class I MHC gene can modulate a virus-induced demyelinating disease process in the mouse.

Expression of human HLA-B27 transgene alters susceptibility to murine Theiler's virus-induced demyelination

Infection of certain strains of mice with Theiler's murine encephalomyelitis virus results in persistence of virus and an immune-mediated primary demyelination in the central nervous system that resembles multiple sclerosis. Because susceptibility/resistance to demyelination in B10 congeneic mice maps strongly to class I MHC genes (D region) we tested whether expression of a human class I MHC gene (HLA-B27) would alter susceptibility to Theiler's murine encephalomyelitis virus-induced demyelination. Transgenic HLA-B27 mice were found to co-express human and endogenous mouse class I MHC genes by flow microfluorimetry analysis of PBL. In the absence of the human transgene, H-2stf, or v mice but not H-2b mice had chronic demyelination and persistence of virus at 45 days after infection. No difference in degree of demyelination, meningeal inflammation, or virus persistence was seen between transgenic HLA-B27 and nontransgenic littermate mice of H-2f or H-2v haplotype. In contrast, H-2s (HLA-B27+) mice showed a dramatic decrease in extent of demyelination and number of virus-Ag+ cells in the spinal cord compared with H-2s (HLA-B27-) littermate mice. In addition, none of the eight H-2s mice homozygous for HLA-B27 gene had spinal cord lesions even though infectious virus was isolated chronically from their central nervous system. Expression of HLA-B27 transgene did not interfere with the resistance to demyelination normally observed in B10 (H-2b) mice. These experiments demonstrate that expression of a human class I MHC gene can modulate a virus-induced demyelinating disease process in the mouse.

Antigenic mimicry and autoimmune diseases

The finding of cross-reactive autoantibodies or sequence homology does not necessarily mean that this molecular mimicry is biologically meaningful or associated with disease pathogenesis. For example, relatives of persons with putative autoimmune insulin-dependent diabetes [123], and elderly humans [124] have a high incidence of autoantibodies which are generally not associated with autoimmune disease. In addition, natural antibodies to cell constituents [125] may be present in normal sera. These antibodies need to be directed against biologically important domains of host cell proteins in order to mediate autoimmune disease [27]. In spite of extensive homology between two sequences, a cross-reactive immune response may not be generated. The dissimilar amino acids should not be radical substitutions or affect the binding properties of the molecule. For instance, antibodies to synthetic peptides with only one substitution in a 19 amino acid sequence may not bind the whole protein [126]. Despite an identical six amino acid sequence shared by HLA-B27 and an EBV protein, no cross-reactive antibodies to EBV peptides were found in HLA-B27 positive patients with AS or RS. Unless the homology and subsequent crossreactive immune response can recognize a host protein intimately involved in disease pathogenesis, autoimmune disease is unlikely to occur.

Antiatherogenic effect of captopril in the Watanabe heritable hyperlipidemic rabbit

The effects of 9 months of orally administered captopril (25-50 mg/kg body wt/day) on aortic atherosclerosis was examined in normotensive Watanabe heritable hyperlipidemic rabbits. Captopril caused a significant decrease in aortic atherosclerosis. Total aortic surface involvement by lesions was reduced from 48 +/- 3.6% in control Watanabe rabbits to 30 +/- 3.9% with captopril treatment (p less than 0.01). Most of the decrease could be accounted for by a marked reduction in atherosclerosis of descending thoracic aortas from 49 +/- 5.2% to 15 +/- 3.9% in control and captopril-related groups, respectively (p less than 0.001). Significant decrease in cholesterol content of descending thoracic aorta was also observed in captopril-treated rabbits. Microscopic examination of the arterial lesions in captopril-treated animals suggested a relative decrease in cellularity and increase in extracellular matrix as compared with untreated animals. These studies indicate that captopril has a potent antiatherosclerotic action in the Watanabe heritable hyperlipidemic rabbit.

Influence of hypertension on aortic atherosclerosis in the Watanabe rabbit

The effects of one-kidney, one clip Goldblatt hypertension on aortic atherosclerosis have been studied in the Watanabe heritable hyperlipidemic (WHHL) rabbit. Renovascular surgery was performed on WHHL rabbits at 3 months of age, and the rabbits were followed for periods of 3-6 months. Aortic atherosclerosis was assessed by measurement of intimal surface involvement with atherosclerotic lesions, determination of aortic free and ester cholesterol content, and microscopic examination. Systolic blood pressure increased by approximately 40-60 mm Hg in the renovascular surgical group as compared with the sham-operated group, but body weight, heart rate, serum cholesterol, and serum triglyceride were unaffected. Aortic atherosclerosis was increased in the hypertensive rabbits, even after 2-3 months of hypertension. At 3 months after renovascular surgery, the aortic surface area covered by atherosclerotic disease averaged 77 +/- 4.4% in hypertensive as compared with 16 +/- 3.3 in control rabbits. At 6 months after surgery, the values were 62 +/- 8.2% and 30 +/- 5.3% in the hypertensive and control rabbits, respectively. The differences in surface involvement and cholesterol content as a result of hypertension were particularly prominent in the descending thoracic aorta. Atherosclerotic lesions in the descending thoracic and abdominal aortic regions of normotensive WHHL rabbits were localized primarily to the ostia of branch vessels, but in the hypertensive rabbits, the involvement was typically very diffuse. No major differences in the nature of atherosclerotic lesions of comparable size were apparent by light microscopy. The results indicate that hypertension accelerates atherogenesis in the WHHL rabbit and suggest that this model may be valuable for studying the mechanisms by which such acceleration is induced.

The use of ultrasound in evaluating problems and complications of genetic amniocentesis

A prospective study of 460 midtrimester amniocenteses performed with ultrasonic guidance was made to determine the problems that occur during amniocentesis and the causes of dry or bloody taps. In 27 instances the needle was seen piercing the fetus. Thickening of the uterine wall, tenting of the membranes, and blocking of flow by the fetus were also observed. The dangers of advancing the needle blindly when no fluid is obtained at the predetermined depth is stressed. The use of active real-time ultrasonic guidance during amniocentesis is advocated.

Induction of ovulation monitored by ultrasound

Eighty menstrual cycles were induced by the administration of human menopausal gonadotropin (hMG), and the induction of ovulation was evaluated by serial ultrasound scanning. Ovulation occurred in 57 of these cycles, and pregnancy occurred in 17 patients. No pregnancy occurred if the follicle size was below 15 mm at the time that human chorionic gonadotropin (hCG) was administered. A 15-mm follicle size is, therefore, regarded as a minimum size for a mature ovum. Multiple follicles were present in seven of the cycles where pregnancy occurred, but only two patients had multiple pregnancies. Ovarian hyperstimulation (OHS), which is characterized by cystic ovarian enlargement of greater than 5 cm after ovulation, was present in 25 cycles. This is a considerably higher incidence than previously documented, but since it is not possible to predict reliably its occurrence, and in no patients were the symptoms severe, it is considered an acceptable and inevitable sequela of ovulation induction. The present role of ultrasound is to establish whether the ovary responds to gonadotropin stimulation, to ensure that the follicle has reached a minimum size, to determine the number of preovulatory follicles to inform better the patient about the possibilities of multiple pregnancies, to establish that ovulation has occurred after administration of hCG, and to document the presence or absence of OHS.