Survey of Management in Acute upper Gastrointestinal Haemorrhage1

The answers to a questionnaire concerning attitudes of members of the British Society of Gastroenterology to the management of acute upper gastrointestinal bleeding are analysed. In the majority of cases patients were admitted to general wards under the care of physicians. Use of intensive therapy units and venous pressure monitoring varied widely. Emergency endoscopy appeared readily available and was usually the first diagnostic procedure. Double contrast radiology and emergency angiography were available in relatively few centres. Specific nonoperative treatments (angiographic and endoscopic) were scarcely employed. Most respondents agreed that elderly patients fared badly, but there was little agreement concerning other factors which influence re-bleeding or outcome. There was a wide divergence of opinion concerning the need for surgical intervention in certain hypothetical clinical situations. Despite the difficulties involved, we believe that controlled trials are necessary to improve the management of bleeding patients.

The role of ¹⁸fluoro-deoxy glucose combined position emission and computed tomography in the clinical management of anal squamous cell carcinoma

AIM

Anal squamous cell carcinoma (SCC) is uncommon in the western world but continues to increase in incidence. Optimal treatment and outcome are dependent upon pretreatment staging strategies. We evaluate the role of ¹⁸fluoro-deoxyglucose (¹⁸FDG) combined position emission and computed tomography (PETCT) in the management of anal SCC.

METHOD

Patients with a histologically confirmed anal SCC underwent standard staging investigations, including computed tomography, Magnetic resonance imaging and examination under anaesthetic. A tumour, node, metastasis (TNM) system was used. All patients subsequently underwent additional whole-body ¹⁸FDG PETCT scanning. Management was planned accordingly, blinded to ¹⁸FDG PETCT findings, at a multidisciplinary meeting, and reviewed again following disclosure of PETCT results.

RESULTS

Forty patients (24 men), with a median age of 57 years (range 38-87 years), were prospectively recruited. All primary tumours were ¹⁸FDG avid. PETCT did not alter the T stage but did result in disease upstaging (N and M stages). Management was altered in five (12.5%) patients: one patient was identified to have an isolated distant metastasis, and four patients had ¹⁸FDG-avid lymph nodes not otherwise detected, all of which were tumour-positive on fine needle aspiration cytology/biopsy.

CONCLUSION

PETCT upstages anal SCC and influences subsequent management. PETCT should be considered in the staging of anal SCC, although the definitive benefit of such a strategy requires further evaluation.

Analysis of innervation of human mesenteric vessels in non-inflamed and inflamed bowel--a confocal and functional study

We investigated the distribution and density of perivascular nerves in human mesenteric arteries and veins and their responses to noradrenaline (NA), ATP and neuropeptide Y (NPY) in control (non-inflamed) and inflamed bowel, using confocal microscopy and in vitro pharmacology. The density of innervation at the adventitial-medial border of arteries and within the medial muscle coat of veins was increased in inflammatory bowel disease (IBD). Expression of markers for both sympathetic nerves and sensory-motor nerves was significantly increased in IBD. Calcitonin gene-related peptide-containing sensory-motor nerves were present in control arteries and IBD, but not in control veins. The density of 5-hydroxytryptamine-containing nerves was variable in controls, but consistently increased (three to four times) in IBD. Vasoactive intestinal peptide (VIP) expression increased (doubled) in arteries and veins. Arteries and veins contracted to NA and ATP, but only veins constricted to NPY. ATP contractions were reduced in arteries and veins in IBD, while contractions to NA were only slightly reduced. Neuropeptide Y induced significantly greater (20%) contractions of IBD veins. In summary, the density of sympathetic and sensory-motor innervation of both mesenteric arteries and veins was increased in IBD. Both 5-hydroxytryptamine and VIP immunoreactivity were also increased. The responses of both arteries and veins to ATP, and to a lesser extent NA, were reduced in IBD while responses to NPY were greater in veins. Decreased responses to ATP indicate changes in purinergic-mediated transmission in the pathological state.

Is MSI-H of value in predicting the development of metachronous colorectal cancer?

Nearly 10% of patients with colorectal cancer (CRC) develop a metachronous cancer after curative resection of their primary malignancy, however identifying these patients is problematic. Although microsatellite instability (MSI) is associated with the development of multiple CRC, this is predominantly seen in those with hereditary non-polyposis colon cancer (HNPCC). This study has examined the value of MSI analysis in identifying patients at risk of developing metachronous cancer from the general population. MSI analysis was performed at the Bat25, Bat26, Bat40, D2S123, D5S346 and D17S250 loci using polymerase chain reaction and single-stranded conformational polymorphism on DNA extracted from 62 specimens taken from 49 patients with metachronous CRC, and from 71 primary single CRCs. MSI status was classified into MSI-H, MSI-L and MSS. MSI-H was more prevalent in metachronous cancers, 34/62 compared to 8/71 single cancers (P < 0.0001). The incidence of MSI-H from proximal colon cancers in index metachronous group, 4/22 was similar to single cancer group, 7/71 (P = 0.28), however MSI-H was more commonly identified in index metachronous cancers located distal to the splenic flexure 9/22 than single cancers 1/71 (P < 0.0001). Patients presenting with MSI-H colorectal cancers distal to the splenic flexure are more likely to develop a metachronous cancer and will benefit from surveillance.

Changes in vasoconstrictor and vasodilator neurotransmitters in nerves supplying arterioles in developing colorectal polyps

OBJECTIVE

To examine the changes that occur in the immunohistochemistry of vasoconstrictor and vasodilator transmitters in nerves supplying early and advanced colorectal polyps.

SUBJECTS AND METHODS

We studied the perivascular innervation of submucosal arterioles of colorectal polyps (n = 18) and the innervation of the epithelial layer of polyps compared to normal controls (n=8), using immunohistochemical markers for the neurotransmitters; noradrenaline (NA) (marker used; tyrosine hydroxylase (TH)), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), substance P (SP), and calcitonin gene-related polypeptide (CGRP). (Advanced polyps; villous adenomas>1.5 cm, polyps with severe dysplasia or partial carcinoma).

RESULTS

In submucosal arterioles there was a progressive decrease from controls through early polyps to advanced polyps in TH and NPY perivascular immunoreactivity (P<0.015 for both). VIP and SP immunoreactivity was higher in early polyps compared to controls, but markedly reduced in advanced polyps (P<0.05 for VIP). Sparse CGRP immunoreactivity was present in polyps only. Neural VIP and SP immunoreactivity in the lamina propria of polyp mucosa was more intense than in controls.

CONCLUSION

There is a decrease in vasoconstrictor neurotransmitters NPY and NA (shown by TH) around submucosal arterioles of both early and advanced polyps, but an increase in the vasodilator neurotransmitters, particularly VIP, in early colorectal polyps. These results suggest a predominantly vasodilatory neural influence in early polyps, perhaps indicating a mechanism that maintains polyp growth.

Improving the morbidity of anorectal injury from pelvic radiotherapy

OBJECTIVE

Radiation anorectal injury due to pelvic radiotherapy for non intestinal cancer is a significant cause of morbidity which may limit the treatment dose required. Conservative treatment options are of limited value and surgery is reserved only for the most severe complications. This review addresses radioprotection of the anorectum and aims to increase awareness amongst surgeons of the strategies that have been in practice in order to minimize the side-effects of radiotherapy while preserving its therapeutic efficacy.

METHODS

This review is based on a literature search (Medline and NLM PubMed) with manual cross-referencing of all articles related to anorectal radiation injury.

RESULTS

Optimization of radiation dose, the use of radioprotective agents and improvement in radiation delivery are the main areas of development. There are few data on the potential of altered fractionation schedules in reducing anorectal injury. A few phase I and II studies suggest that the pharmacological agents amifostine and misoprostol could be beneficial in limiting radiation damage but larger phase III studies are awaited.

CONCLUSION

The introduction of 3-dimensional conformal radiation therapy and intensity modulated radiation therapy has been the most significant advance in reducing radiation morbidity.

The role of MLH1, MSH2 and MSH6 in the development of multiple colorectal cancers

There is increased incidence of microsatellite instability (MSI) in patients who develop multiple primary colorectal cancers (CRC), although the association with hereditary nonpolyposis colon cancer (HNPCC) is unclear. This study aims to evaluate the underlying genetic cause of MSI in these patients. Microsatellite instability was investigated in 111 paraffin-embedded CRCs obtained from 78 patients with metachronous and synchronous cancers, and a control group consisting of 74 cancers from patients with a single CRC. Tumours were classified as high level (MSI-H), low level (MSI-L) or stable (MSS). MLH1, MSH2 and MSH6 gene expression was measured by immunohistochemistry. Methylation of the MLH1 promoter region was evaluated in MSI-H cancers that failed to express MLH1, and mutational analysis performed in MSI-H samples that expressed MLH1, MSH2 and MSH6 proteins. The frequency of MSI-H was significantly greater in the multiple, 58 out of 111 (52%), compared to the single cancers, 10 out of 74 (13.5%), P < 0.01. Of the 32 patients from whom two or more cancers were analysed, eight (25%) demonstrated MSI-H in both cancers, 13 (41%) demonstrated MSI-H in one cancer and 11 (34%) failed to demonstrate any MSI-H. MSI-H single cancers failed to express MLH1 or MSH2 in seven out of nine (78%) cases and MSI-L/MSS cancers failed to express MLH1 or MSH2 in one out of 45 (2.2%) cases, all cancers expressed MSH6. MSI-H multiple cancers failed to express MLH1 or MSH2 in 21 out of 43 (48%) cases and MSI-L/MSS cancers failed to express MLH1 or MSH2 in four out of 32 (12.5%) cases. MSH6 expression was lost in five MSI-H multiple cancers, four of which also failed to express MLH1 or MSH2. Loss of expression of the same mismatch repair (MMR) gene was identified in both cancers from six out of 19 (31%) patients. Methylation was identified in 11 out of 17 (65%) multiple and three out of six (50%) single MSI-H cancers that failed to express MLH1. Mutational analysis of 10 MSI-H multiple cancers that expressed MLH1, MSH2 and MSH6 failed to demonstrate mutations in the MLH1 or MSH2 genes. We suggest that, although MSI-H is more commonly identified in those with multiple colorectal cancers, this does not commonly arise from a classical HNPCC pathway.

Anal intraepithelial neoplasia

Background

Anal intraepithelial neoplasia (AIN) is believed to be a precursor of anal squamous cell cancer and its incidence is rising in high-risk groups, particularly those infected with the human immunodeficiency virus (HIV). The natural history of AIN is unclear and management strategies are lacking.

Methods

This review is based on a literature search (Medline and PubMed) with manual cross-referencing of all articles related to AIN.

Results and conclusions

The aetiology of AIN is intricately linked with human papilloma viruses. The pathological processes involved in the progression of AIN are becoming clearer but the natural history, particularly the rate of progression to invasive cancer, remains unknown. There is no standard management for AIN and this is mainly due to difficulties in both diagnosis and treatment. A variety of treatment options have been tried with varying success. Surgery is associated with significant recurrence, particularly in HIV-positive patients. Non surgical approaches with imiquimod, photodynamic therapy and vaccination are appealing, and further work is required. Long-term follow-up of these patients is essential until the natural history of AIN becomes clearer.

Activity (transcription) of the genes for MLH1, MSH2 and p53 in sporadic colorectal tumours with micro-satellite instability

Micro-satellite instability (MSI) is relevant in the management of colorectal cancers (CRC) and relies on analysis of gene mutations, or production of the proteins involved in DNA mismatch repair (e.g. MLH1, MSH2). p53 mutation is also relevant in MSI, but high-level CRC (MSI-H) demonstrate fewer mutations than low-level (MSI-L) or stable (MSS) cancers. Recently, the importance of gene activity (transcription) in MSI has been identified, where rather than being mutated genes have been downregulated. In this study, 67 sporadic CRC and eight samples of normal bowel were analysed for MSI status (by SSCP) and levels of MLH1, MSH2 and p53 gene transcription (by RT–PCR and scanning densitometry). Micro-satellite instability correlated with gender and site, with more MSI-H CRC in females (P<0.02) and in the right colon (P<0.04). In MSI-H, p53 transcription was markedly reduced (P<0.003). Compared to normal bowel, MLH1 transcription was elevated in all cancers (P<0.01), while MSH2 transcription was elevated only in MSI-H (P<0.04). There was a direct correlation between MLH1 and MSH2 transcription (P<0.001). Although fewer mutations are reported in MSI-H than MSI-L/MSS, these results suggest that reduced p53 transcription might account for decreased tumour suppression in MSI-H. The direct correlation between MLH1 and MSH2 transcription suggests that control of these genes might be coordinated.

The clinical importance and prognostic implications of microsatellite instability in sporadic cancer

AIMS

The genetic abnormality known as microsatellite instability (MSI), first identified in colorectal cancer in 1993, has subsequently been recognised in other malignancies. These cancers are caused by a defect in the nuclear mismatch repair system, allowing mutations to accumulate with every cellular division. Hereditary Non Polyposis Colon Cancers (HNPCC) and associated malignancies demonstrating MSI have a unique histological appearance, improved prognosis and altered response to chemotherapy and radiotherapy. This review examines the incidence of MSI and its clinical significance in commonly occurring solid malignancies.

METHOD

A medline based literature search was performed using the key words 'Microsatellite Instability' and the name of the specific malignancy being investigated. Additional original papers were obtained from citations in those articles identified in the original medline search.

RESULTS

MSI has been detected in many solid malignancies although the definition of instability applied has been variable. It is most commonly found in sporadic malignancies that also occur in the HNPCC syndrome such as colorectal, stomach, endometrial and ovarian cancer. MSI may impart a favorable prognosis in colorectal, gastric, pancreatic and probably oesophageal cancers but a poor prognosis in non small cell lung cancer. In clinical studies colorectal cancers demonstrating MSI respond better to chemotherapy while in vitro studies using MSI positive cell lines show resistance to radiotherapy and chemotherapy.

CONCLUSION

MSI may be a useful genetic marker in prognosis and could be an influential factor in deciding treatment options. However, in many cancers its significance remains unclear and more evaluation is required.

Possible absence of Helicobacter pylori in the early stages of duodenal ulceration

BACKGROUND

Helicobacter pylori is thought to be a cause of duodenal ulceration, but there is some evidence that it is found less often in early than in later disease.

AIM

To assess the presence of H. pylori in patients undergoing endoscopy for dyspepsia, with respect to their duration of symptoms.

DESIGN

Retrospective case note review.

METHODS

Patients were categorized as having a history greater or less than 6 months, and as H. pylori-positive or -negative, using biopsy rapid urease, culture and PCR tests.

RESULTS

Thirty-two duodenal ulcer patients with a history >6 months were all H. pylori-positive according to the PCR test; the five with a shorter history were H. pylori-negative. No patient H. pylori-negative by PCR was positive by the other tests.

DISCUSSION

H. pylori was (at least) less commonly present before 6 months. It is possible that H. pylori, although nearly always present after 6 months, is not present at the onset of the disease. Confirmation of this finding would imply that infection with the organism is not the cause of duodenal ulceration, but a factor producing recurrence and chronicity.

Pathogenesis and clinical management of hereditary non-polyposis colorectal cancer

BACKGROUND

Hereditary non-polyposis colorectal cancer (HNPCC) is an inherited genetic condition associated with microsatellite instability; it accounts for around 5 per cent of all cases of colorectal cancer. This review examines recent data on management strategies for this condition.

METHODS

A Medline-based literature search was performed using the keywords 'HNPCC' and 'microsatellite instability'. Additional original papers were obtained from citations in articles identified by the initial search.

RESULTS AND CONCLUSION

The Amsterdam criteria identify patients in whom the presence of an inherited mutation should be investigated. Those with a mutation should be offered counselling and screening. The role of prophylactic surgery has been superseded by regular colonoscopy, which dramatically reduces the risk of colorectal cancer. Screening for extracolonic malignancy is also advocated, but the benefits are uncertain. Chemoprevention may be of value in lowering the incidence of bowel cancer in affected patients, but further studies are required.

Complicated diverticulosis

"Uncomplicated" diverticulitis can be prevented from progressing into "complicated" diverticulitis by early diagnosis and active medical treatment. Complicated diverticulitis develops from a peridiverticular abscess, to a perforation with peritonitis, to fistulation into adjacent viscera, to luminal narrowing by inflammation or stricture formation causing obstruction. Computer tomography (CT) scanning is the diagnostic imaging modality when diverticulitis is suspected and allows percutaneous drainage of peridiverticular abscesses that will enhance the effect of antibiotic therapy with resolution of the acute episode in 75% of patients. Thus, an emergent or urgent operation is converted to an elective operation and a two-stage operative procedure, namely a temporary stoma and a second operation, is avoided. Interventional surgery is urgent for perforation and obstruction. While a Hartmann's resection and temporary colostomy has been the favoured operative procedure, under favourable conditions resection with primary anastomosis is preferable. Although a temporary stoma may be required with primary anastomosis, and hence the procedure is a two-stage one similar to a Hartmann's, the closure of the stoma is less demanding and has a lower morbidity. A single-stage resection and anastomosis is the standard elective treatment for symptomatic fistulas and strictures.

Regulation of matrix metalloproteinases in a model of colonic wound healing in a rabbit

PURPOSE

Matrix metalloproteinases occur in the colon at an anastomosis but not in the normal colon. Matrix metalloproteinase synthesis can be regulated by cytokines, for example interleukin-1 beta and growth factors, such as transforming growth factor beta and basic fibroblast growth factor. The aim of this study was to investigate the regulation of matrix metalloproteinases at an anastomosis by identifying the cell types that synthesize matrix metalloproteinases, examining factors that might regulate their synthesis, determining whether they occur in an active form, and assessing the effect of suture type on these parameters.

METHODS

An anastomosis was formed in the distal colon of rabbits using either polyglactin or polydioxanone and the animals were killed six hours or seven days later. The distribution of matrix metalloproteinases and cytokines and the cell types were assessed by immunohistochemistry. Matrix metalloproteinase-2, matrix metalloproteinase-3, and matrix metalloproteinase-9 were detected also by zymography.

RESULTS

Immunohistochemistry showed that matrix metalloproteinases were restricted to the suture line. Although zymography demonstrated that matrix metalloproteinase-2 was present mainly in an active form, matrix metalloproteinase-9 and matrix metalloproteinase-3 were present in the pro-form. The active form of matrix metalloproteinase-3 occurred more often in the polydioxanone-sutured rabbits. With the exception of matrix metalloproteinase-9, the matrix metalloproteinases were synthesized by fibroblasts. Interleukin-1 beta and transforming growth factor beta were more widespread than in the normal colon and were localized adjacent to the matrix metalloproteinases. Basic fibroblast growth factor was also more widespread postoperatively but occurred deeper in the anastomosis than the matrix metalloproteinases.

CONCLUSIONS

This study has shown that interleukin-1 beta and transforming growth factor beta may regulate the synthesis of the matrix metalloproteinases by fibroblasts and that minor differences that occur in the matrix metalloproteinase profile are dependent on the suture type.

Increased endothelin-1 in colorectal cancer and reduction of tumour growth by ET(A) receptor antagonism

Endothelin-1 (ET-1) is a vasoconstrictor peptide which stimulates proliferation in vitro in different cell types, including colorectal cancer cells. Raised ET-1 levels have been detected both on tissue specimens and in the plasma of patients with cancers. To investigate the role of ET-1 in colorectal cancer: (i) ET-1 plasma levels in patients with colorectal cancer were measured by radioimmunoassay: group 1 = controls (n = 22), group 2 = primary colorectal cancer only (n = 39), group 3 = liver metastases only (n = 26); (ii) ET-1 expression in primary colorectal cancer specimens (n =10) was determined immunohistochemically and (iii) the effect of intraportally infused antagonists to the two ET-1 receptors, ET(A) and ET(B), on the growth of liver metastases in a rat model was assessed. ET-1 plasma levels were significantly increased in both patients with primary tumour and patients with metastases, compared to controls (P < 0.01, 3.9 +/- 1.4, 4.5 +/- 1.5, vs. 2.75 +/- 1.37 pg/ml, respectively). Immunohistochemically, strong expression of ET-1 was found in the cytoplasm, stroma and blood vessels of cancers, unlike the normal colon where only the apical layer of the epithelium, vascular endothelial cells and surrounding stroma were positively stained. In the rat model, there was significant reduction in liver tumour weights compared to controls, following treatment with the ET(A) antagonist (BQ123) 30 min after the intraportal inoculation of tumour cells (P < 0.05). These results suggest ET-1 is produced by colorectal cancers and may play a role in the growth of colorectal cancer acting through ET(A) receptors. ET(A) antagonists are indicated as potential anti-cancer agents.

Anorectal irradiation in pelvic radiotherapy: an assessment using in-vivo dosimetry

The objectives of this study were to measure by in-vivo techniques the radiation doses received by the anorectum during pelvic radiotherapy and compare these with doses predicted by a GE TARGET treatment planning system. Nine patients with cancers of the prostate, bladder, cervix or uterus were planned with computed tomography (CT) using the TARGET system. A Scanditronix rectal probe containing five n-type photon-detecting diodes was placed in the anorectum during the planning CT scans. The probe position was standardized with the five diodes at 2 cm intervals from the anal verge. The probe diodes were calibrated for 10 MV photons. Doses were measured for each diode for two consecutive fractions in the first four patients and for five consecutive fractions in the remaining five. Thermoluminescent dosimeters were used initially to verify diode doses. The TARGET and diode measured doses were compared. In all patients diodes situated in the target volume were within 7% of predicted doses. This improved to 2.5% after measurement on five fractions. At the edges of the target volume, wide variability existed between measured and predicted doses (measured dose range -68% to +68% of predicted dose). Outside the target volume, considerable doses (up to 0.3 Gy per fraction) were measured in the anal canal, which were not predicted by TARGET. We conclude that TARGET planned doses are accurate within the confines of the target volume. The greatest variability was seen at the edges of the target volume, where dose can vary by 50% across a 1 cm distance in the anterior-posterior plane. TARGET does not account for scattered dose beyond the field edges and therefore underestimates the dose received by the anal canal.

Anorectal injury following pelvic radiotherapy

BACKGROUND

Current knowledge of the effects of radiation on the anorectum is based on a limited number of studies. Variability in delivery techniques, both currently and historically, combined with a paucity of prospective and randomized studies makes interpretation of the literature difficult. This review presents the existing evidence and identifies areas that require further work.

METHODS

This review is based on a literature search (Medline and PubMed) and manual cross-referencing.

RESULTS AND CONCLUSION

More than three-quarters of patients receiving pelvic radiotherapy experience acute anorectal symptoms and up to one-fifth suffer from late-phase radiation proctitis. About 5 per cent develop other chronic complications, such as fistula, stricture and disabling faecal incontinence. The risk of rectal cancer may be increased. Conservative treatment options are of limited value. Surgery may be considered if symptoms are severe, provided sphincter function is adequate and recurrent disease is excluded. Large prospective studies with accurate dosimetric data and long-term follow-up are needed to provide meaningful information on which to base new strategies to minimize the side-effects from radiotherapy.

A double-blind randomized placebo-controlled trial of oral indoramin to treat chronic anal fissure

BACKGROUND

Indoramin is an alpha1-adrenoceptor antagonist and has been shown to reduce anal resting pressure. Its therapeutic potential has not been explored. The aim of this study was to determine the outcome of treatment with oral indoramin on patients with chronic anal fissure in the setting of a double-blind randomized placebo-controlled trial.

METHODS

Twenty-three patients with chronic anal fissure were computer randomized to receive a 6-week course of oral indoramin (20 mg) or placebo in identical capsules, twice daily and with bulk-forming laxatives. Pain was assessed by a visual analogue scale from 0 to 10. Anal resting pressure, heart rate and blood pressure were recorded. Patients were reviewed 1 h after taking the capsule and at 2, 6 and 12 weeks thereafter.

RESULTS

Fourteen patients were randomized to indoramin and 9 to placebo. Maximum anal resting pressure was reduced from a mean of 96.4 cm H2O (+/- 32) to 67.6 cm H2O (+/- 26), 1 h after indoramin (P=0.02) and there was no significant change after placebo. There were no significant changes in heart rate or blood pressure. Pain was reduced in the placebo group from a score of 4.9 to 2.0 after 6 weeks (P < 0.01) but not in the indoramin group. After 6 weeks, healing had occurred in one (7%) patient in the indoramin group and in 2 (22%) in the placebo group (P > 0.1). After 3 months, the chronic anal fissure in the indoramin group had recurred. The trial was terminated early because of poor healing rates.

CONCLUSION

An oral dose of indoramin (20 mg) administered twice daily reduced anal resting pressure by 30% compared with pretreatment levels but was ineffective in healing chronic anal fissures.

Progressive loss of perivascular nerves adjacent to colorectal cancer

AIMS

The perivascular innervation of arterioles in colorectal cancer and adjacent submucosa was investigated.

METHODS

Neurotransmitter markers, neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP) and tyrosine hydroxylase (TH), were studied and immunoreactivity was compared with that of control normal tissue.

RESULTS

There was absence of perivascular nerves within tumours and loss of perivascular innervation in the submucosa adjacent to the tumour. The pattern of loss varied for different transmitters. The loss was progressively greater with advancing tumour stage for NPY (controls 95%, Dukes' A 68%, Dukes>> B 13%, Dukes' C 6%) and VIP (50%, 23%, 20%, 17%). For TH there was extensive loss of innervation around tumours of all stages (69%, 5%, 7%, 0%). SP immunoreactive peri-arteriolar nerves were similar in control tissue (39%) and tissue adjacent to Dukes' A tumours (40%) but diminished to 19% and 0% in tissue adjacent to Dukes' B and C tumours, respectively. In none of the tissues was CGRP immunoreactivity above 4%. The mean distance over which there was reduced NPY immunoreactivity from the tumour edge was 2.43 mm for Dukes' A/B tumours compared with 7.20 mm for Dukes' C tumours; for VIP immunoreactivity this distance was 5.22 mm for Dukes' A/B tumours and 5.52 mm for Dukes' C tumours.

CONCLUSIONS

The progressive loss, both in terms of vascular nerve immunoreactivity and distance from the tumour edge with tumour grade, suggests that the tumour itself may influence neural integrity in perivascular plexuses, perhaps via the secretion of an inhibitory factor.

Alpha-1 adrenoceptor blockade: potential new treatment for anal fissures

PURPOSE

Patients with chronic anal fissures are known to have high resting anal pressures that return to normal after successful surgical treatment. Internal anal sphincter activity is increased by sympathetic excitatory innervation via alpha adrenoceptors. The objective of this study was to determine the effect of alpha-1 adrenoceptor blockade on anal sphincter pressure in patients with and without chronic anal fissures.

METHODS

The effect on the anal canal pressure profile of a single oral 20 mg dose of indoramin, an alpha-1 adrenoceptor antagonist, on seven patients with chronic anal fissure and six healthy patients without a fissure was investigated.

RESULTS

Indoramin reduced anal resting pressures in those with anal fissure by a mean of 35.8 percent, from 106.9 +/- 22.15 cm H2O to 68.6 +/- 20.35 cm H2O, and in those without anal fissure by a mean of 39.9 percent, from 84.17 +/- 27.46 cm H2O to 52.17 +/- 24.78 cm H2O, after one hour. This pressure reduction persisted at three hours, and its magnitude is comparable to that obtained after internal sphincterotomy. The pressure reduction occurred over the whole length of the anal canal.

CONCLUSION

It is proposed that alpha-1 adrenoceptor antagonists could be a suitable treatment for chronic anal fissure and other painful conditions where reduction in anal pressure is warranted.

Neuromyogenic properties of the internal anal sphincter: therapeutic rationale for anal fissures

Lateral sphincterotomy diminishes internal anal sphincter hypertonia and thereby reduces anal canal pressure. This improves anal mucosal blood flow and promotes the healing of anal fissures. However, sphincterotomy can be associated with long term disturbances of sphincter function. The optimal treatment for an anal fissure is to induce a temporary reduction of anal canal resting pressure to allow healing of the fissure without permanently disrupting normal sphincter function. Broader understanding of the intrinsic mechanisms controlling smooth muscle contraction has allowed pharmacological manipulation of anal sphincter tone. We performed an initial Medline literature search to identify all articles concerning "internal anal sphincter" and "anal fissures". This review is based on these articles and on additional publications obtained by manual cross referencing. Internal anal smooth muscle relaxation can be inhibited by stimulation of non-adrenergic non-cholinergic enteric neurones, parasympathetic muscarinic receptors, or sympathetic beta adrenoceptors, and by inhibition of calcium entry into the cell. Sphincter contraction depends on an increase in cytoplasmic calcium and is enhanced by sympathetic adrenergic stimulation. Currently, the most commonly used pharmacological agent in the treatment of anal fissures is topical glyceryl trinitrate, a nitric oxide donor. Alternative agents that exhibit a similar effect via membrane Ca2+ channels, muscarinic receptors, and alpha or beta adrenoceptors are also likely to have a therapeutic potential in treating anal fissures.

Metachronous colorectal cancers

BACKGROUND

Up to 9 per cent of patients who undergo resection for colorectal cancer develop metachronous cancers. There is no consensus on the detection and management of such cancers.

METHODS

The literature was reviewed exhaustively regarding the incidence, clinical characteristics, detection, treatment and molecular genetics of metachronous colorectal cancers. This was based on a Medline search from 1966 to December 1997 for articles on metachronous colorectal cancers. A manual search was also performed on references quoted in these articles. All publications relevant to this study were included.

RESULTS

Although the underlying causes for metachronous colorectal cancers are yet to be elucidated, risk factors for the disease have been identified. These include the presence of synchronous polyps or cancers, a history of metachronous cancers, and hereditary non-polyposis colorectal cancer (HNPCC).

CONCLUSION

Preoperative colonoscopy and postoperative colonoscopic surveillance are essential in identifying patients at risk of metachronous colorectal cancer. A total colectomy and ileorectal anastomosis should be considered for some patients, certainly for those with HNPCC.

Helical CT pneumocolon to assess colonic tumors: radiologic-pathologic correlation

OBJECTIVE

The objective of this study was to determine the accuracy of helical CT pneumocolon in the staging of colonic carcinomas.

SUBJECTS AND METHODS

Fifty-two patients (27 men, 25 women; age range, 40-88 years old; mean age, 67 years old) with known or strongly suspected colonic disorders underwent CT pneumocolon. After bowel cleansing, administration of smooth muscle relaxant, and rectal air insufflation, CT pneumocolon was performed with 5-mm collimation, 2.5-mm reconstruction interval, and a pitch of 1.5. Two contrast administration protocols were used. Twelve patients received 100 ml of i.v. contrast material that was injected at 3 ml/sec; scan delay was 45 sec. The other 40 patients received 150 ml of contrast material at 5 ml/sec; scan delay was 25 sec. Images were prospectively evaluated. All patients had pathologic confirmation: 46 patients had resections and six patients had endoscopic biopsies.

RESULTS

Diagnostic images were obtained in 47 of 52 patients. In the 47 patients, there were 38 colonic carcinomas (one synchronous), nine diverticular strictures, eight polyps, one ischemic stricture, and one normal study. Thirty of 38 carcinomas were correctly staged by CT. Sensitivity and specificity for serosal infiltration were 100% (35/35 carcinomas) and 33% (one of three carcinomas), respectively; sensitivity and specificity for lymph node involvement were 56% (nine of 16 carcinomas) and 95% (21/22 carcinomas), respectively. Four polyps that were smaller than 5 mm in diameter were not revealed by CT. Twelve of 14 benign lesions were correctly diagnosed and two were believed to be malignant. No malignant lesion was misdiagnosed.

CONCLUSION

CT pneumocolon gave an overall staging accuracy of 79% in 38 carcinomas.

Raised endothelin 1 levels in patients with colorectal liver metastases

BACKGROUND

Endothelin 1 (ET-1), a vasoconstrictor peptide, has been implicated as a tumour growth stimulator and an angiogenesis factor.

METHODS

To assess the involvement of ET-1 in colorectal cancer, immunoelectron microscopy for ET-1 was performed in colorectal liver metastases and normal liver (n = 6). ET-1 plasma levels were measured by radioimmunoassay in patients with colorectal cancer, with (n = 18) and without (n = 12) liver metastases, and in controls (n = 22).

RESULTS

In normal liver, ET-1 was present in endothelial cells; in tumour, it was observed in endothelial cells, tumour cells and myofibroblasts. Mean(s.d.) plasma ET-1 levels were 2.75 (1.37) pg/ml in controls, 4.53(1.61) pg/ml in patients with colorectal liver metastases (P = 0.001) and 3.92(1.32) pg/ml in patients without metastases (P = 0.02).

CONCLUSION

ET-1 was present in various cell types within colorectal liver metastases and raised levels were found in the plasma of patients with colorectal cancer. ET-1 may not only modulate tumour vascular tone but also act on tumour growth and angiogenesis, both locally and systemically.

Effect of colonic obstruction on the distribution of matrix metalloproteinases during anastomotic healing

BACKGROUND

Anastomotic dehiscence is common after surgery for colonic obstruction. The strength of an anastomosis is dependent on collagen, which is degraded by matrix metalloproteinases (MMPs). The aim of this study was to determine the distribution of the MMPs and their inhibitor, tissue inhibitor of metalloproteinases (TIMP) 1 in an experimental model of colonic obstruction, with and without resection and anastomosis.

METHODS

The distal colon of rabbits was obstructed with a Silastic ring for 24 h and then either the ring was removed or the obstructed segment was resected and an anastomosis formed. Rabbits were killed immediately or at intervals for up to 7 days after operation. The distribution of the MMPs and TIMP-1 was examined by indirect immunofluorescence.

RESULTS

MMPs and TIMP-1 were present throughout the descending colon for 24 h in both groups. They persisted to the third day in rabbits with an anastomosis but by day 7 were restricted to the suture line. Their presence correlated with microscopic damage.

CONCLUSION

The extensive distribution of the MMPs suggests that these enzymes contribute to anastomotic dehiscence, but only in the immediate postoperative period.

Role of matrix metalloproteinases in healing of colonic anastomosis

PURPOSE

The aim of this study was to compare the distribution of the matrix metalloproteinases (MMPs) during anastomotic healing in a normal colon with that in an ischemic colon in a rabbit. This family of enzymes degrades all components of connective tissue and has been implicated as a cause of anastomotic dehiscence.

METHODS

A left-sided anastomosis was formed in the distal colon of one group of rabbits, and in the other group, 9 cm of distal colon was made ischemic before resection and anastomosis 12 hours later. Tissues from the anastomosis and sites around the colon were removed at 12 hours, 1 day, and 3 days after anastomosis and, also, at 7 days in the normal group. Distribution of the MMPs and their inhibitor, tissue inhibitor of metalloproteinases (TIMP), was localized by indirect immunofluorescence.

RESULTS

In rabbits having only an anastomosis, the MMPs and TIMP-1 were, at all times, seen solely in the anastomotic segment and were strictly confined to the immediate vicinity of the suture line. While in rabbits with an ischemic colon before anastomosis, the MMPs initially extended several centimeters proximally and distally from the suture line. By the third day, however, there were only minor differences between the two models.

CONCLUSION

Distribution of the MMPs and TIMP-1 in normal healing is consistent with a role in the remodeling of colonic anastomosis, but when healing of the colon is compromised, these enzymes are more widespread and may contribute to anastomotic dehiscence.

Genetic instability in patients with metachronous colorectal cancers

BACKGROUND

Nearly 7 per cent of patients who undergo resection for colorectal cancer develop metachronous cancers several years later. A molecular marker that could identify patients susceptible to metachronous cancers would be of clinical importance.

METHODS

Twenty-four colorectal cancers from 15 individuals with metachronous colorectal cancer were investigated for microsatellite instability at five loci by single stranded conformational polymorphism analysis. A control group of 14 colorectal cancers from individuals who had only developed one sporadic colorectal cancer each was analysed similarly.

RESULTS

Microsatellite instability was demonstrated in 17 of 24 cancers from individuals with metachronous cancer compared with one of 14 cancers from individuals with a single colorectal cancer.

CONCLUSION

These results suggest that testing for microsatellite instability may be useful in recognizing patients at high risk of developing metachronous colorectal cancers.

Neurochemical coding in the small intestine of patients with Crohn's disease

BACKGROUND

There have been conflicting results regarding the effect of Crohn's disease on the neurochemical composition of the enteric nervous system.

AIMS

To examine the effect of Crohn's disease on the neurochemical composition of enteric nerve fibres and cell bodies using whole mount preparations of human ileum.

METHODS

Whole wall ileum from seven normal subjects and nine patients with Crohn's disease was used to investigate the neurochemical composition of neurones and nerve fibres in the myenteric plexus, circular muscle, and serosa layer of ileum using immunohistochemical techniques.

RESULTS

Increased tyrosine hydroxylase, 5-hydroxytryptamine, and neuropeptide Y immunoreactivity was exclusively seen in the myenteric plexus. There was increased neurofilament immunoreactivity in the myenteric plexus and nerve fibres of the circular muscle layer, and thick bundles of immunoreactive nerve fibres in the serosa layer. Increased vasoactive intestinal polypeptide, nitric oxide synthase, and pituitary adenylate cyclase activating peptide immunoreactivity was seen in the myenteric plexus and nerve fibres of the circular muscle layer, and aggregates of inflammatory cells in the serosa layer of the afflicted segment of Crohn's ileum. In addition, there was a chaotic display of nerve fibres containing some of the neuroactive substances with a high frequency of enlarged varicosities in the myenteric ganglia and/or nerve fibres of the circular muscle layer of Crohn's ileum.

CONCLUSION

Results show quantitative as well as qualitative changes in the neurochemical composition of enteric nerve fibres and nerve cell bodies of Crohn's ileum. These changes and the presence of nitric oxide synthase and peptides immunoreactive inflammatory cells in the serosa layer suggest that nerve-immune interactions may have a significant role in the process of the inflammatory changes seen in Crohn's ileitis.

[The effect of the physico-chemical properties of suture materials and the surface structure on adherence of tumor cells]

Local recurrence following curative resection for colorectal cancer may be caused by the seeding of free malignant cells at the anastigmatic site. This study investigated the influence of suture material on in vitro tumor cell adherence. Radiolabeled rat colonic cancer cells (RCC5) were incubated with a variety of suture materials, and the relative contribution of chemical composition and physical configuration to cell adherence was assessed. Nonadherent cells were washed free, and the cell adherence was determined by radioactive counting. Marked differences in adherence were observed, with cells preferentially adhering to protein-based and multifilament sutures. These observations were confirmed using scanning electron microscopy. These findings indicate that both chemical composition and physical configuration influence the adherence of tumor cells to sutures and suggest that the use of protein-based and multifilament sutures be carefully considered in situations where free malignant cells may be present following colorectal surgery.

Technical report: spiral CT pneumocolon for suspected colonic neoplasms

Abdominal spiral computed tomography (CT) pneumocolon is performed after cleansing the colon, using a smooth muscle relaxant and rectal air insufflation. Rapid dynamic scanning is undertaken with intravenous contrast to give optimal hepatic and vascular enhancement, and 5-10 mm contiguous slices. The area of interest in the colon is reconstructed every 2.5 mm. This technique was performed in four patients with colorectal cancer and the CT findings were compared with the barium enema and pathology following surgical resection. Spiral CT pneumocolon clearly showed the primary tumour in all cases as an enhancing soft tissue mass, and was able to detect local extension and lymphadenopathy as well as assess the liver, peritoneum and remaining abdomen. CT depicted the morphology of the primary tumour more clearly than barium enema, and in one case also detected a 1 cm polyp which was not seen on the barium study because the patient was incontinent of barium and views were limited. There was good correlation between the CT and pathological findings. Compared to a barium enema, spiral CT pneumocolon is quick, with minimal patient discomfort, no risk of barium incontinence, and there is good assessment of the local and distant abdominal disease. Multiplanar formatting is possible and 3-D reconstruction gives intra- and extra-luminal views.

The distribution of matrix metalloproteinases and tissue inhibitor of metalloproteinases in colorectal cancer

Studies suggest that the interplay between matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitor of metalloproteinases (TIMPs), is an important mediator of tumour invasion and metastasis. Using immunohistochemistry, 40 specimens of colorectal cancer were examined for the presence of TIMP-1 and the MMPs, stromelysin, gelatinases A and B and interstitial collagenase. Neither enzyme nor TIMP-1 was detected in histologically normal mucosa. Within malignant tissue, stromelysin and gelatinase A were conspicuously absent in tumour cells but were immunolocalized to the extracellular matrix and for gelatinase A also to peritumoural fibroblast-like cells. Gelatinase B was confined to polymorphonuclear leucocytes. Interstitial collagenase was not identified. TIMP-1 was present in only three of the 40 tumours within the malignant stroma. These observations suggest that the mesenchymal elements of colorectal carcinomas, by acting as a source of MMPs and TIMPs, may modulate tumour invasion.

The distribution of matrix metalloproteinases and tissue inhibitor of metalloproteinases in colorectal cancer

Studies suggest that the interplay between matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitor of metalloproteinases (TIMPs) is an important mediator of tumour invasion and metastasis. Using immunohistochemistry, 40 specimens of colorectal cancer were examined for the presence of TIMP-1 and the MMPs, stromelysin, gelatinases A and B and interstitial collagenase. Neither enzyme nor TIMP-1 was detected in histologically normal mucosa. Within malignant tissue, stromelysin and gelatinase A were conspicuously absent in tumor cells but were immunolocalized to the extracellular matrix and for gelatinase A also to peritumoural fibroblast-like cells. Gelatinase B was confined to polymorphonuclear leucocytes. Interstitial collagenase was not identified. TIMP-1 was present in only three of the 40 tumours within the malignant stroma. These observations suggest that the mesenchymal elements of colorectal carcinomas, by acting as a source of MMPs and TIMPs, may modulate tumour invasion.

Influence of temporary faecal diversion on long-term survival after curative surgery for colorectal cancer

Experimental carcinogenesis is enhanced at colorectal anastomoses, inhibited by proximal faecal diversion and promoted by the closure of a defunctioning stoma. The clinical relevance of these observations was investigated in a retrospective study of curative restorative resection for colorectal carcinoma. The 5-year disease-free survival rate (95 per cent confidence interval) in 122 patients with a temporary stoma (50.4 (41.1-59.7) per cent) was significantly reduced (P < 0.01) compared with that in 218 with no stoma (66.8 (59.4-73.5) per cent). In patients with Dukes B tumours early stoma closure (within 3 months of resection) was associated with a worse survival (P < 0.005) and a higher tumour recurrence rate (P < 0.05) than in those with no stoma. Survival rates after late stoma closure were no different from those in patients with no stoma. Multivariate analysis revealed Dukes stage (P < 0.0001), tumour differentiation (P = 0.02) and timing of stoma closure (P = 0.02) as independent predictors of survival. In curative surgery for colorectal cancer temporary faecal diversion confers a survival disadvantage that can be prevented by delayed closure of the stoma.

Detection of free malignant cells in the peritoneal cavity before and after resection of colorectal cancer

PURPOSE

This study was designed to select the best monoclonal antibody to stain malignant cells in peritoneal wash fluid, and to investigate the incidence of free malignant cells in preresection and postresection colorectal cancer peritoneal washings using a combination of conventional cytology and immunocytochemistry.

METHODS

Peritoneal washings were taken from 35 consecutive patients undergoing colorectal cancer resection.

RESULTS

Malignant cells were isolated on a density gradient and identified by conventional cytology and an indirect immunoperoxidase stain. Malignant cells were identified in peritoneal washings from 15 patients (preresection only n = 3, postresection only n = 4, both n = 8). The origin of free malignant peritoneal cells in 11 preresection-positive washings must be the serosa. The origin of these cells in the four postresection-positive patients is uncertain: serosal and luminal spillage were considered unlikely and no circulating cells were found in the mesenteric vessels near the tumor.

CONCLUSION

Tumor cells may have leaked out from lymphatics cut during the dissection.

Intra-abdominal sepsis and survival after surgery for colorectal cancer

Of 361 patients who survived curative left colonic or sphincter-saving rectal resection for cancer, 44 developed significant postoperative intra-abdominal sepsis and 317 did not. The two groups were well matched for age, sex, site of tumour, Dukes stage, tumour differentiation and timing of operation. There was no significant difference in the 5-year overall actuarial survival rate (P = 0.25) or in the 5-year disease-free survival rate (P = 0.23). Stepwise regression analysis of prognostic variables including age, sex, site of tumour, Dukes stage, tumour differentiation, timing of operation, grade of surgeon and postoperative intra-abdominal sepsis identified Dukes stage, age at operation and tumour differentiation as predictors of survival. These results suggest that postoperative intra-abdominal sepsis is not a prognostic factor for long-term survival in colorectal cancer as has been previously reported.

Effects of the H2-antagonists famotidine and nizatidine and the cytoprotectant misoprostol on human colonic and rat peritoneal mast cells

The H2-antagonists famotidine and nizatidine produced a dose-dependent inhibition of histamine release from human colonic mucosal and muscle mast cells stimulated with anti-IgE. The IC30 values were in the range 0.5-10 microM and the maximum inhibition approached 50%. The compounds showed similar efficacy against rat peritoneal mast cells but were more potent. The cytoprotectant misoprostol had a striking effect on the human colonic mast cells, producing more than 50% inhibition at concentrations of 0.1-1 nM, but was much less active against the rat cells.

Survival in colorectal carcinoma associated with previous extracolonic cancer

Between 1971 and 1990, 1198 patients presented with a primary colorectal cancer, of whom 70 patients (5.8%) had survived previous extracolonic primary malignancies. Complete data were available on 63 cases (metachronous group) of the 70 patients, who had a total of 67 previous extracolonic cancers. Clinical and pathological characteristics of these cases were identical to the remaining patients with primary colorectal cancer (primary group, n = 1128), except that the former group was significantly older, P < 0.05. In the metachronous group there was a preponderance of breast, female genital, gastric, urological, lung and skin cancers, and the median time to develop a colorectal primary tumour was 7 years. The 5-year overall actuarial survival was better in the metachronous group, log rank test: chi 2 = 4.07, P = 0.04. In the metachronous group, 44 patients who had undergone curative resection were matched with patients with primary colorectal cancer (control group, n = 88) in the ratio of 1:2 based on age, sex, tumour site, Dukes' stage, tumour differentiation, grade of surgeon and date of operation. Comparison between these groups showed a significantly better survival in the former group, log rank test: chi 2 = 5.99, P = 0.01. These results suggest that patients with colorectal cancer and a history of previous extracolonic tumours have similar clinicopathological features as the general colorectal cancer population but have a better survival.

Long-term outcome of patients presenting with acute complications of diverticular disease

The immediate management of acute diverticular disease is well defined but the risk of further complications and the long-term course of the disease, after conservative or surgical treatment, is not clearly documented. Over an 8-year period, a total of 164 patients (male/female = 69/95, median age 68 years) presented with acute complications of diverticular disease and were prospectively followed up for a median of 48 months. Medical treatment of acute diverticulitis was effective in 85% of 86 patients, with a mortality of 1.3% and a recurrence rate of 2% per patient year follow-up. All 37 patients presenting with bleeding responded to conservative management without mortality and a readmission rate, with further bleeding, of 5% per patient year. Patients who required colonic resection (n = 52), either as a single or staged procedure, had a mortality of 12% but with no further admissions with complications of diverticular disease. The low risk of readmission with recurrent disease after successful conservative treatment of the acute complications of diverticular disease does not justify elective operation in this group of patients.

Influence of suture physicochemical and surface topographic structure on tumor cell adherence

Local recurrence following curative resection for colorectal cancer may be caused by the seeding of free malignant cells at the anastomotic site. This study investigated the influence of suture material on in vitro tumor cell adherence. Radiolabeled rat colonic cancer cells (RCC5) were incubated with a variety of suture materials, and the relative contribution of chemical composition and physical configuration to cell adherence was assessed. Nonadherent cells were washed free, and the cell adherence was determined by radioactive counting. Marked differences in adherence were observed, with cells preferentially adhering to protein-based and multifilament sutures. These observations were confirmed using scanning electron microscopy. These findings indicate that both chemical composition and physical configuration influence the adherence of tumor cells to sutures and suggest that the use of protein-based and multifilament sutures be carefully considered in situations where free malignant cells may be present following colorectal surgery.

Loss of cell-cell and cell-matrix adhesion molecules in colorectal cancer

Adhesion molecules are thought to play a vital role in the induction and maintenance of tissue differentiation and their loss or down-regulation has been implicated in the neoplastic process. Recent studies have shown that the morphoregulatory activities are a consequence of interactive processes between several cell adhesion molecules rather than the function of a single molecule. Therefore, we have investigated a panel of adhesion molecules including members of the integrin, cadherin and immunoglobin superfamily in colorectal cancer. Twenty-eight consecutive colorectal adenocarcinomas were stained using an avidin-biotin indirect immunoperoxidase technique. Our results showed a consistent loss of the alpha 2 and beta 1 integrin subunits (21/28 = 75% and 22/28 = 78.6% respectively) and a decrease in expression of E-cadherin in 5/5 poorly differentiated adenocarcinomas. Carcinoembryonic antigen expression was preserved but with basolateral accentuation seen in tumours. There was no statistical correlation with Dukes' stage. These results provide further evidence that in colorectal cancer there is a widespread deregulated expression of cell-cell and cell-matrix adhesion molecules. Changes in the expression and function of adhesion molecules which regulate growth and differentiation may play a role in the behaviour of colorectal cancer.