AGA Clinical Practice Update on the Role of Artificial Intelligence in Colon Polyp Diagnosis and Management: Commentary

DESCRIPTION

The purpose of this American Gastroenterological Association (AGA) Institute Clinical Practice Update (CPU) is to review the available evidence and provide expert commentary on the current landscape of artificial intelligence in the evaluation and management of colorectal polyps.

METHODS

This CPU was commissioned and approved by the AGA Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the CPUC and external peer review through standard procedures of Gastroenterology. This Expert Commentary incorporates important as well as recently published studies in this field, and it reflects the experiences of the authors who are experienced endoscopists with expertise in the field of artificial intelligence and colorectal polyps.

Evidence-based clinical practice guidelines for management of colorectal polyps

BACKGROUND

The Japanese Society of Gastroenterology (JSGE) published ''Daicho Polyp Shinryo Guideline 2014'' in Japanese and a part of this guideline was published in English as "Evidence-based clinical practice guidelines for management of colorectal polyps" in the Journal of Gastroenterology in 2015. A revised version of the Japanese-language guideline was published in 2020, and here we introduce a part of the contents of revised version.

METHODS

The guideline committee discussed and drew up a series of clinical questions (CQs). Recommendation statements for the CQs were limited to items with multiple therapeutic options. Items with established conclusions that had 100% agreement with previous guidelines (background questions) and items with no (or old) evidence that are topics for future research (future research questions: FRQs) were given descriptions only. To address the CQs and FRQs, PubMed, ICHUSHI, and other sources were searched for relevant articles published in English from 1983 to October 2018 and articles published in Japanese from 1983 to November 2018. The Japan Medical Library Association was also commissioned to search for relevant materials. Manual searches were performed for questions with insufficient online references.

RESULTS

The professional committee created 18 CQs and statements concerning the current concept and diagnosis/treatment of various colorectal polyps, including their epidemiology, screening, pathophysiology, definition and classification, diagnosis, management, practical treatment, complications, and surveillance after treatment, and other colorectal lesions (submucosal tumors, nonneoplastic polyps, polyposis, hereditary tumors, ulcerative colitis-associated tumors/carcinomas).

CONCLUSIONS

After evaluation by the moderators, evidence-based clinical practice guidelines for management of colorectal polyps were proposed for 2020. This report addresses the therapeutic related CQs introduced when formulating these guidelines.

Reducing the polyp burden in serrated polyposis by serial colonoscopy: the impact of nationally coordinated community surveillance

BACKGROUND

Serrated polyposis syndrome (SPS) is associated with an increased risk of colorectal cancer (CRC) and an evolving management approach. The aims of this study were to assess the polyp burden reduction over time, and the incidence of CRC in serrated polyposis patients undergoing community surveillance.

METHODS

This is an observational study based on prospectively collected data. A total of 96 SPS patients with no personal history of CRC were prospectively enrolled in a surveillance program under the guidance of a tertiary center. Patients underwent surveillance colonoscopy in multiple centres across New Zealand.

RESULTS

Patients underwent a median of four colonoscopies with a median interval of 15 months over a median follow-up period of 4.8 years. Five of 96 patients (5%) were referred for surgery, and the remaining 91 were managed by colonoscopy alone. In patients referred for surgery, 92% of the surveillance intervals to the fourth colonoscopy had been ≤12 months compared to 33% (P<0.001) in the colonoscopy only group, and all five (100%) had ≥20 pancolonic polyps after four procedures compared with only 5/91 (5%) in those managed by colonoscopy alone. In patients successfully managed by colonoscopy, 86% had <10 pancolonic polyps, >75% no longer had polyps ≥10mm and >90% no longer had proximal serrated polyps ≥10mm after the fourth colonoscopy. No patients were found to develop CRC during the study time period.

CONCLUSIONS

Patients with SPS were managed by proactive surveillance colonoscopy in wider hospital settings under tertiary centre guidance, with only 5% requiring surgical management. No CRC was diagnosed in any patient during surveillance.

Feasibility of full-spectrum endoscopy: Korea’s first full-spectrum endoscopy colonoscopic trial

AIM: To evaluate the full-spectrum endoscopy (FUSE) colonoscopy system as the first report on the utility thereof in a Korean population.

METHODS: We explored the efficacy of the FUSE colonoscopy in a retrospective, single-center feasibility study performed between February 1 and July 20, 2015. A total of 262 subjects (age range: 22-80) underwent the FUSE colonoscopy for colorectal cancer screening, polyp surveillance, or diagnostic evaluation. The cecal intubation success rate, the polyp detection rate (PDR), the adenoma detection rate (ADR), and the diverticulum detection rate (DDR), were calculated. Also, the success rates of therapeutic interventions were evaluated with biopsy confirmation.

RESULTS: All patients completed the study and the success rates of cecal and terminal ileal intubation were 100% with the FUSE colonoscope; we found 313 polyps in 142 patients and 173 adenomas in 95. The overall PDR, ADR and DDR were 54.2%, 36.3%, and 25.2%, respectively, and were higher in males, and increased with age. The endoscopists and nurses involved considered that the full-spectrum colonoscope improved navigation and orientation within the colon. No colonoscopy was aborted because of colonoscope malfunction.

CONCLUSION: The FUSE colonoscopy yielded a higher PDR, ADR, DDR than did traditional colonoscopy, without therapeutic failure or complications, showing feasible, effective, and safe in this first Korean trial.

Obesity and Colorectal Cancer

There is strong evidence that modifiable lifestyle factors such as obesity play a key role in colorectal carcinogenesis. Epidemiologic data have consistently reported a positive association between obesity and colorectal cancer. The relative risk associated with general obesity (as assessed by BMI) is higher in men than in women and for cancer of the colon than for cancer of the rectum. Abdominal obesity (as assessed by waist circumference (WC) or waist-to-hip ratio) is associated with an increased risk of colorectal cancer in both sexes, with stronger associations for cancer of the colon than for cancer of the rectum. Plausible biological mechanisms include insulin resistance, hyperinsulinemia, chronic inflammation, altered levels of growth factors, adipocytokines and steroid hormones. In addition to its effect on colorectal cancer incidence, obesity may play a role in colorectal cancer recurrence, treatment outcomes and survival. Understanding the effects of childhood and adolescent obesity and weight change over the life course in relation to future risk of colorectal cancer is incomplete but essential for targeted preventive recommendations. This chapter summarizes the current evidence on the relationship between obesity and colorectal cancer and colorectal adenoma, a common precursor lesion.

Interval colorectal carcinoma: An unsolved debate

Colorectal carcinoma (CRC), as the third most common new cancer diagnosis, poses a significant health risk to the population. Interval CRCs are those that appear after a negative screening test or examination. The development of interval CRCs has been shown to be multifactorial: location of exam-academic institution versus community hospital, experience of the endoscopist, quality of the procedure, age of the patient, flat versus polypoid neoplasia, genetics, hereditary gastrointestinal neoplasia, and most significantly missed or incompletely excised lesions. The rate of interval CRCs has decreased in the last decade, which has been ascribed to an increased understanding of interval disease and technological advances in the screening of high risk individuals. In this article, we aim to review the literature with regard to the multifactorial nature of interval CRCs and provide the most recent developments regarding this important gastrointestinal entity.

British Society of Gastroenterology/Association of Coloproctologists of Great Britain and Ireland guidelines for the management of large non-pedunculated colorectal polyps

These guidelines provide an evidence-based framework for the management of patients with large non-pedunculated colorectal polyps (LNPCPs), in addition to identifying key performance indicators (KPIs) that permit the audit of quality outcomes. These are areas not previously covered by British Society of Gastroenterology (BSG) Guidelines.A National Institute of Health and Care Excellence (NICE) compliant BSG guideline development process was used throughout and the Appraisal of Guidelines for Research and Evaluation (AGREE II) tool was used to structure the guideline development process. A systematic review of literature was conducted for English language articles up to May 2014 concerning the assessment and management of LNPCPs. Quality of evaluated studies was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) Methodology Checklist System. Proposed recommendation statements were evaluated by each member of the Guideline Development Group (GDG) on a scale from 1 (strongly agree) to 5 (strongly disagree) with >80% agreement required for consensus to be reached. Where consensus was not reached a modified Delphi process was used to re-evaluate and modify proposed statements until consensus was reached or the statement discarded. A round table meeting was subsequently held to finalise recommendations and to evaluate the strength of evidence discussed. The GRADE tool was used to assess the strength of evidence and strength of recommendation for finalised statements.KPIs, a training framework and potential research questions for the management of LNPCPs were also developed. It is hoped that these guidelines will improve the assessment and management of LNPCPs.

Endoscopy and polyps-diagnostic and therapeutic advances in management

Despite multiple efforts aimed at early detection through screening, colon cancer remains the third leading cause of cancer-related deaths in the United States, with an estimated 51000 deaths during 2013 alone. The goal remains to identify and remove benign neoplastic polyps prior to becoming invasive cancers. Polypoid lesions of the colon vary widely from hyperplastic, hamartomatous and inflammatory to neoplastic adenomatous growths. Although these lesions are all benign, they are common, with up to one-quarter of patients over 60 years old will develop pre-malignant adenomatous polyps. Colonoscopy is the most effective screening tool to detect polyps and colon cancer, although several studies have demonstrated missed polyp rates from 6%-29%, largely due to variations in polyp size. This number can be as high as 40%, even with advanced (> 1 cm) adenomas. Other factors including sub-optimal bowel preparation, experience of the endoscopist, and patient anatomical variations all affect the detection rate. Additional challenges in decision-making exist when dealing with more advanced, and typically larger, polyps that have traditionally required formal resection. In this brief review, we will explore the recent advances in polyp detection and therapeutic options.

Cap polyposis: A rare cause of rectal bleeding in children

AIM: To evaluate the clinicopathological features and treatment outcomes of cap polyposis in the pediatric population.

METHODS: All pediatric patients with histologically proven diagnosis of cap polyposis were identified from our endoscopy and histology database over a 12 year period from 2000-2012 at our tertiary pediatric center, KK Women’s and Children’s Hospital in Singapore. The case records of these patients were retrospectively reviewed. The demographics, clinical course, laboratory results, endoscopic and histopathological features, treatments, and outcomes were analyzed. The study protocol was approved by the hospital institutional review board. The histological slides were reviewed by a pediatric histopathologist to confirm the diagnosis of cap polyposis.

RESULTS: Eleven patients were diagnosed with cap polyposis. The median patient age was 13 years (range 5-17 years); the sample included 7 males and 4 females. All of the patients presented with bloody stools. Seven patients (63%) had constipation, while 4 patients (36%) had diarrhea. All of the patients underwent colonoscopy and polypectomies (excluding 1 patient who refused polypectomy). The macroscopic findings were of polypoid lesions covered by fibrinopurulent exudates with normal intervening mucosa. The rectum was the most common involvement site (n = 9, 82%), followed by the rectosigmoid colon (n = 3, 18%). Five (45%) patients had fewer than 5 polyps, and 6 patients (65%) had multiple polyps. Histological examination of these polyps showed surface ulcerations with a cap of fibrin inflammatory exudate. Four (80%) patients with fewer than 5 polyps had complete resolution of symptoms following the polypectomy. One patient who did not consent to the polypectomy had resolution of symptoms after being treated with sulphasalazine. All 6 patients with multiple polyps experienced recurrence of bloody stools on follow-up (mean = 28 mo).

CONCLUSION: Cap polyposis is a rare and under-recognised cause of rectal bleeding in children. Our study has characterized the disease phenotype and treatment outcomes in a pediatric cohort.

Serrated pathway: alternative route to colorectal cancer

Serrated polyps have been an area of intense focus for gastroenterologists over the past several years. Contrary to what was thought before, a growing body of literature indicates that these polyps can be precursors of colorectal cancer (CRC). Most of these lesions, particularly those in the proximal colon, have so far been under-recognized and missed during colonoscopy, qualifying these lesions to be the main cause of interval cancers. It is estimated that 10%-20% of CRCs evolve through this alternative, serrated pathway, with a distinct genetic and epigenetic profile. Aberrant DNA methylation plays a central role in the development of this CRC subtype. This characteristic molecular background is reflected in a unique pathological and clinical manifestation different from cancers arising via the traditional pathway. In this review we would like to highlight morphological, molecular and clinical features of this emerging pathway that are essential for gastroenterologists and may influence their everyday practice.

Postpolypectomy bleeding in patients undergoing colonoscopy on uninterrupted clopidogrel therapy

BACKGROUND

The risk of postpolypectomy bleeding (PPB) in patients undergoing colonoscopy on uninterrupted clopidogrel therapy has not been established.

OBJECTIVE

To assess the PPB rate and outcome and identify risk factors associated with PPB in patients taking clopidogrel.

DESIGN

Single-center, retrospective study. Demographics, clinical parameters, polyp characteristics, polypectomy techniques, and postpolypectomy events in the groups were compared by univariate analysis. Stepwise logistic regression analyses identified independent risk factors associated with PPB.

SETTING

Veterans Affairs Medical Center.

PATIENTS

A total of 142 patients (375 polypectomies) taking clopidogrel (cases) and 1243 patients (3226 polypectomies) not taking clopidogrel (controls).

INTERVENTIONS

None.

MAIN OUTCOME MEASUREMENTS

Postpolypectomy bleeding, hospitalization, and mortality.

RESULTS

The immediate (intraprocedural) bleeding rate was similar in the 2 groups (2.1% vs 2.1%). Delayed (postprocedural) PPB rate was higher in the group taking clopidogrel (3.5% vs 1.0%, P = .02). Delayed bleeding of significance requiring hospitalization and transfusion/intervention was also higher in patients taking clopidogrel (2.1% vs 0.4%, P = .04). The length of hospital stay and interventions for PPB were comparable between the 2 groups. There was no mortality. Concomitant use of clopidogrel and aspirin/other nonsteroidal anti-inflammatory drugs (odds ratio 3.7; 95% CI, 1.6-8.5) and the number of polyps removed (OR 1.3; 95% CI, 1.2-1.4) were the only significant risk factors associated with PPB. Clopidogrel alone was not an independent risk factor for PPB.

LIMITATIONS

Retrospective study and small number of patients with PPB.

CONCLUSIONS

The PPB rate is significantly higher in patients undergoing polypectomy while taking clopidogrel and concomitant aspirin/nonsteroidal anti-inflammatory drugs; however, the risk is small and the outcome is favorable. Routine cessation of clopidogrel in patients before colonoscopy/polypectomy is not necessary.

Epinephrine volume reduction of giant colon polyps facilitates endoscopic assessment and removal

BACKGROUND

Management of giant colon polyps (>3 cm) can be a challenge for the therapeutic endoscopist, especially the endoscopist in training. Challenges include the potential for bleeding and the difficult technical aspects of removing giant polyps. Years of clinically observing the effects of epinephrine injection to reduce bleeding revealed epinephrine's pronounced volume-reducing effect. This epinephrine volume reduction (EVR) greatly facilitates assessment and removal of giant polyps while decreasing the need for piecemeal resection.

OBJECTIVE

Our purpose was to demonstrate the use of EVR in facilitating the evaluation and removal of giant colon polyps.

DESIGN

Case reports defining the technique of EVR.

SETTING

Busy ambulatory endoscopy center with more than 22,000 cases in 2006.

PATIENTS

General population of patients treated in this ambulatory endoscopy center for giant colon polyps.

INTERVENTIONS

EVR and polypectomy.

OUTCOME MEASUREMENTS

Pre-EVR and post-EVR volumes in giant polyps. Relative ease of removal of pre-EVR versus post-EVR polyp and observations for complications.

RESULTS

Typically greater than 80% reduction in polyp volume was achieved, greatly easing endoscopic evaluation and removal while virtually eliminating the need for piecemeal resection. EVR was associated with no acute or delayed bleeding complications.

LIMITATIONS

May be limited by inexperienced endoscopist's lack of injection and polypectomy skills. The technical difficulty in objective measurements of in vivo size and lack of blinded observations with a control group present the potential for observer bias.

CONCLUSIONS

The use of EVR is a simple, cheap, and practical tool that facilitates giant polyp assessment and removal. This technique may greatly benefit endoscopists in the management of giant colon polyps. A prospective controlled trial of EVR should be undertaken to further define the optimal methods and benefits for the removal of giant colon polyps.

Laparoscopic colonoscopic rendezvous procedures for the treatment of polyps and early stage carcinomas of the colon

BACKGROUND AND AIMS

Endoscopic treatment of large or colonoscopically inaccessible polyps or early stage tumors in the colon holds the risk of incomplete resection and colonic perforation. The combination of colonoscopy and laparoscopy offers a minimally invasive treatment modality for the complete resection of polyps with low risk. Aim of this study was to assess the feasibility and outcome of patients operated on by laparoendoscopic rendezvous procedures at the colon.

MATERIALS AND METHODS

The medical records of 38 patients (21 male, 17 female, median age 66 years [range 39-90]) undergoing rendezvous surgery at the colon were reviewed prospectively. Follow-up data were obtained by clinical examination and personal communication via telephone or questionnaire. The median follow up was 54 months.

RESULTS

From January 1998 until April 2007, 38 patients were treated with rendezvous procedures in our hospital. In 30 cases, a colonoscopically assisted laparoscopic procedure was performed and in eight patients a laparoscopically controlled colonoscopic procedure. A benign lesion was confirmed histologically in 31 patients. In five cases, histopathologic diagnosis revealed a malignancy necessitating colonic surgery. A coprolith extraction and a suture of the sigma were performed in one case each. Complications occurred in two patients. One patient developed an anastomosis insufficiency that necessitated a revision. One patient developed pneumonia postoperatively. A conversion to laparotomy had to be performed in two cases.

CONCLUSION

Rendezvous procedures offer a safe, minimal-invasive therapeutic approach allowing the resection of benign sessile or colonoscopically inaccessible localized polyps and of early stage colon cancer.

Large bowel endoscopy and management of colorectal cancer and its premalignant forms--endoscopy survey

PURPOSE

To estimate the relationships between patients' clinical variables like age and sex with the endoscopical and histological findings of colorectal lesions and to assess the efficacy of endoscopy in diagnosing and treating polyps and early forms of colorectal cancer (CRC).

PATIENTS AND METHODS

Analyzed were patients included in our database who were subjected to lower gastrointestinal tract endoscopy at our department for the last 15 years.

RESULTS

5107 patients were examined. In almost 1/5 (955) of them, the examination was for surveillance purposes. Women/men: 55%/45%. The number of patients with polyps was 1180. Polyps were diagnosed most frequently in patients aged 51-60 years and were located mostly in the sigmoid colon (43%). Patients with CRC were 613 and were diagnosed predominantly in the age group of 60-70 years (32%), most frequently in the rectum (38%), followed by the sigmoid colon (32%). 128 patients were diagnosed with early CRC. In 52 (40.62%) of them successful endoscopic therapy was carried out. No serious complications were observed except one case of late perforation after polypectomy, with a successful outcome.

CONCLUSION

Lower gastrointestinal endoscopy is a highly efficient method for screening, diagnosis and therapy of colorectal polyps and early forms of CRC. It is still underused for screening purposes in patients after the age of 50 years.

Twelve years of endoscopic surveillance in a family carrying biallelic Y165C MYH defect: report of a case

PURPOSE

We report the case of two siblings, clinically andendoscopically followed for 12 years, who displayed anattenuated adenomatous polyposis coli phenotype.

METHODS

On workup for rectal bleeding with colonoscopy, we found multiple adenomas mainly right-sided in a 21-year-old female and the same colonic phenotype was observed in her 27-year-old brother. We made a clinical diagnosis of attenuated adenomatous polyposis coli and performed APC gene testing. Because they had refused the proposed ileorectal anastomosis surgical option, we planned a periodic, endoscopic follow-up.

RESULTS

Gene testing did not confirm the clinical suspicion of attenuated adenomatous polyposis coli. Actually, we did not find anypathogenic mutation in APC gene and we recently identified a biallelic Y125C MYH defect. During the endoscopic follow-up, a progressive reduction of adenomas was seen.

CONCLUSIONS

New insight colorectal cancer genetics have allowed definition of a new class of polyposis that applies to some patients with attenuated adenomatous polyposis coli phenotype as in the siblings we have described. To prevent colorectal cancer without recurring to surgery, colonoscopic polypectomy may be a suitable tool in controlling MYH polyposis.

Colorectal neoplasm and acromegaly

The risk for colorectal carcinoma in acromegaly remains controversial. In our earlier study, we have demonstrated that the risk of colorectal carcinoma in Asian Indians with acromegaly is not increased and after this report, routine colonoscopy in our patients with acromegaly was abandoned. Subsequently, two consecutive young men aged 30 and 35, one 6 years after and other at the time of diagnosis of acromegaly had colorectal carcinoma respectively. None of them had family history of colonic neoplasm. These two younger patients with no other predisposition for colorectal neoplasm suggests that colonoscopy should be done in all patients with acromegaly at diagnosis and they should remain under surveillance.

Colorectal cancer: what the clinician wants to know

Colorectal cancer is a common and lethal disease. The adenoma-carcinoma sequence offers a window of opportunity in which the precursor lesion or early carcinoma can be removed endoscopically to prevent systemic disease. New and advanced techniques to improve endoscopic detection of precursor lesions are being developed. Other, less invasive screening methods are currently being developed and may become of use for population-based screening in the near future. Recently, important developments in the treatment (both surgical and chemotherapeutic) of colorectal cancer have occurred. The extent of the disease (stage) forms the basis for therapeutic decisions and accurate imaging is crucial.

The Munich Polypectomy Study (MUPS): prospective analysis of complications and risk factors in 4000 colonic snare polypectomies

BACKGROUND AND STUDY AIMS

Screening colonoscopy with polypectomy has been shown to reduce the morbidity and mortality associated with colorectal cancer. However, there is a lack of large and systematic prospective studies of the complications of polypectomy.

PATIENTS AND METHODS

Data on all snare polypectomies performed in 13 institutions (six hospitals and seven gastroenterology offices) were recorded prospectively during a 20-month period, including data on a 30-day follow-up period. The primary end points of the study were polypectomy complications, which were classed as "major" or "minor". Risk factors for complications were analyzed for both patient characteristics and polyp parameters.

RESULTS

A total of 3976 snare polypectomies in 2257 patients (mean age 64.5 years) were included in the study. The mean polyp size was 1.1 cm, and 72% were sessile. Complications occurred in 9.7% of patients (6.1% of polyps); 75% of these complications were minor; and the mortality rate was zero. Multivariate regression analysis revealed polyp size as the main risk factor, both for complications overall (odds ratio 6.56, 95%CI 4.45-9.67) and for major complications (odds ratio 31.01, 95%CI 7.53-128.1). Right-sided polyp location was a significant risk factor for major complications (odds ratio 2.40, 95%CI 1.34-4.28). Setting a cut-off value of 3% as an acceptable rate for major complications, polyps larger than 1 cm in the right colon or 2 cm in the left colon, and multiple polyps carried an increased risk.

CONCLUSIONS

Colonoscopic polypectomy is associated with a 10% rate of complications, but three-quarters of these are of minor clinical significance. More than 90% of the complications can be managed conservatively if adequate endoscopic expertise is available. Guidelines for intensified follow-up after polypectomy should be based on the size, location, and number of a patient's polyps.

Advances in treatment of colorectal cancer

The purpose of this review is to provide the practicing surgeon with an outline of several significant developments in colorectal cancer treatment that have affected the care of patients. This review is not intended to report on every important publication of the past few years nor is it intended to be encyclopedic. The author simply hopes to provide a useful reference for surgeons in their daily practice.

Colon Cancer Clinical Practice Guidelines in Oncology

Colorectal cancer is the third most frequently diagnosed cancer in men and women in the United States, and in 2005, an estimated 104,950 new cases of colon cancer will occur. Despite these statistics, mortality from colon cancer has decreased over the past 30 years, possibly because of earlier diagnosis through screening and better treatment modalities. The NCCN guidelines summarize the management of colon cancer, from disease presentation through management of recurrent disease and patient surveillance.

For the most recent version of the guidelines, please visit NCCN.org

Are we overtreating some patients with rectal cancer?

The definition of overtreatment of rectal cancer is controversial, and thus it is difficult to accurately quantitate its prevalence. All components of rectal cancer treatment are associated with significant potential for morbidity and dysfunction that may have a negative impact on the patient's quality of life. No one would disagree with the tenet that overtreatment should be avoided whenever possible. Despite that consensus, little attention is given in the literature to the issues of overtreatment of rectal cancer. This review article presents a variety of clinical scenarios and summarizes available data demonstrating that overtreatment of some patients with rectal cancer is occurring on a regular basis. It is hoped that this will stimulate clinicians to critically review their own practices to eliminate such overtreatment. Development of new clinical trials to determine whether current practice guidelines are promoting overtreatment of selected rectal cancer patients is proposed.

Colorectal Polyposis and Immune-Based Therapies

The progression from precancerous (adenomatous) colon polyps to malignant colorectal cancer involves the complex actions of various cytokines on T cell proliferation, cell-cell adhesion, apoptosis and host immunity. A broad spectrum of new treatments, including innovative molecular therapies such as gene therapy and treatment with cytokines, is under experimental and preclinical investigation. Nonsteroidal anti-inflammatory drugs and selective cyclooxygenase-2 inhibitors have traditionally been used as inflammation-reducing agents in cases of colon adenoma. Currently, adjuvant immunotherapies such as recombinant gene therapy and antibody-cytokine fusion proteins are assuming a more significant role in the management of colorectal neoplasia. Furthermore, advances in antitumour necrosis factor antibodies for the treatment of ulcerative colitis and Crohn's disease may have potential as chemoprotective agents for the treatment of colon polyposis. The present review aims to discuss the immunological mechanisms underlying colon tumour progression and the molecular and immune-based therapies that are leading to new methods of prognosis and treatment.

Endoscopic snare polypectomy for bleeding postinflammatory polyps

We describe a patient with ulcerative colitis and protracted rectal bleeding who had required several blood transfusions and who was unresponsive to medical therapy, whose symptoms resolved after endoscopic resection of multiple giant postinflammatory polyps. This case report highlights the fact that postinflammatory polyps can occasionally cause significant symptoms, such as rectal bleeding, and that in these circumstances careful endoscopic polypectomy can be performed safely and result in a significant improvement in symptoms over a prolonged period of follow-up.

The Norwegian Colorectal Cancer Prevention (NORCCAP) screening study: baseline findings and implementations for clinical work-up in age groups 50-64 years

BACKGROUND

Randomized controlled trials of sufficient power testing the long-term effect of screening for colorectal neoplasia only exist for faecal occult blood testing (FOBT). There is indirect evidence that flexible sigmoidoscopy (FS) may have a greater yield. The aim of this study was to determine the diagnostic yield of screening with FS or a combination of FS and FOBT in an average-risk population in an urban and combined urban and rural population in Norway.

METHODS

20,780 men and women (1:1), aged 50-64 years, were invited for once-only screening (FS only or a combination of FS and FOBT (1:1)) by randomization from the population registry. A positive FS was defined as a finding of any neoplasia or any polyp > or = 10 mm. A positive FS or FOBT qualified for colonoscopy.

RESULTS

Overall attendance was 65%. Forty-one (0.3%) cases of CRC were detected. Any adenoma was found in 2208 (17%) participants and 545 (4.2%) had high-risk adenomas. There was no difference in diagnostic yield between the FS and the FS and FOBT group regarding CRC or high-risk adenoma. Work-up load comprised 2821 colonoscopies in 2524 (20%) screenees and 10% of screenees were recommended later colonoscopy surveillance. There were no severe complications at FS, but six perforations after therapeutic colonoscopy (1:336).

CONCLUSIONS

The present study bodes well for future management of a national screening programme, provided that follow-up results reflect adequate proof of a net benefit. It is highly questionable whether the addition of once-only FOBT to FS will contribute to this effect.

Colorectal polyps in the elderly: what should be done?

Colorectal cancer is an important cause of morbidity and mortality among Western nations, and is more common in the elderly than in younger individuals. With the general acceptance of the adenoma-carcinoma sequence, the current consideration is that colorectal cancer is preventable if all adenomas are removed before they have the chance to progress to cancer. To that end, physicians should now advocate screening for colorectal cancer and through this effort a large number of patients with adenomatous polyps will be discovered. It is important to understand the strategy in dealing with this growing population of patients with adenomas. After an initial polypectomy, patients with adenomas should be entered into a surveillance program to detect and remove recurrent adenomas. Recommended surveillance intervals are shorter for patients with a family history of colorectal cancer, those with multiple adenomas (>2), large adenomas (> or = 1cm), or those whose adenomas have high-grade dysplasia, villous architecture, or that are cancerous. Effective chemoprevention would be a potential method of lengthening colonoscopic surveillance intervals. Unfortunately, no treatment has been found to be effective enough to alter our current surveillance practice. The only recommendation that can be made at this time for those patients with a history of colonic adenomas is to add 3 g/day of calcium carbonate to their diet, though its effect on adenoma recurrence is modest.

Lifestyle-related factors and colorectal polyps: preliminary results from a Norwegian follow-up and intervention study

Lifestyle-related variables are suggested to play a major role in the development of colorectal cancer (CRC). Within a 3-year follow-up and intervention study with calcium and antioxidants against growth and recurrence of colorectal polyps, supplementary studies were performed in which different aspects of lifestyle were examined. Instead of polypectomy at diagnosis, polyps <9 mm were left in situ in 116 polyp patients (50-76 years, 50% men). After 3 years, all polyps were removed and subjected to histology. Two different sets of control groups were included (all controls were age- and sex-matched and proven to be free of polyps). We applied two different methods in order to assess most exposure variables. Generally, in case-control studies, the validity of the study outcomes is high if they are similar regardless of choice of controls and methods, since bias due to these choices may affect the risk estimates. In contrast, the validity of the study outcomes is low if dependent upon these choices. Our preliminary data support the theory that different factors may be of importance in different stages of the neoplastive formation, and that lifestyle-related factors are likely to play a major role in CRC development.

[Construction and application of colorectal polyp database]

OBJECTIVE

To study the construction and application of computerized database of colorectal polyp in the clinical management and research of this disease.

METHOD

A colorectal polyp database and its management system was constructed on the basis of Microsoft Access 2000. Clinical, endoscopic and pathological data, which went through standardized and elemental processing, of 2 627 cases (4 850 records) of colorectal polyp collected from 1990 to 2000 in Nanfang Hospital was entered into this database.

RESULTS

Using this new database, the information on the population and age distribution, location and clinical features of colorectal polyps were obtained. Comparative study of the clinical and pathological findings in the cases, evaluation of the therapeutic effects, statistical review of the identification of the polyp and its canceration in the previous years as well as the analysis of other relevant factors were successfully accomplished, which greatly facilitated the follow-up study of some chosen cases that may be of clinical significance.

CONCLUSIONS

Applications of modern informatics and computer technology greatly facilitates case management and clinical research of colorectal polyps, and standardized and elemental processing of the clinical data offers a new possibility for easy case information management.

Polyposis syndromes: pediatric implications

The diagnosis of a polyposis syndrome, such as juvenile polyposis, Peutz-Jeghers syndrome, and familial adenomatous polyposis, requires knowledge of the site, number, and histologic type of the polyps and an appreciation of relevant family history. Children and adolescents with polyposis syndromes are faced with not only the immediate complications of the polyps, such as intussusception or bleeding, but also the extraintestinal manifestations and the long-term risk for malignancy. This article reviews the diagnosis, clinical management, surveillance, and surgical options for children with polyposis syndromes and discusses genetics and appropriate screening programs.

Successful treatment of cap polyposis by avoidance of intraluminal trauma: clues to pathogenesis

"Cap polyposis" is a rarely-encountered condition in which distinctive inflammatory polyps are located from the rectum to the distal descending colon. Microscopically, the polyps consist of elongated, tortuous, and distended crypts covered by a "cap" of inflammatory granulation tissue. Although the pathogenesis is unknown, mucosal prolapse has been postulated to be an important etiological factor, given certain clinical and histological similarities. We describe two cases of cap polyposis with protein-losing enteropathy. One was treated successfully by avoidance of straining at defecation. Another resolved after double-barreled transverse colostomy. Both successful treatments support a causal link of polyposis to prolapse.

Effect of calcium supplementation on serum cholesterol and blood pressure. A randomized, double-blind, placebo-controlled, clinical trial

OBJECTIVE

To test the effect of daily supplemental calcium on serum total and high-density lipoprotein cholesterol (HDL-C) levels and blood pressure in adults.

DESIGN

Randomized, double-blind, placebo-controlled clinical trial; adjunct study to a trial of calcium and colon cell proliferation in patients with sporadic adenoma.

SETTING

Outpatient clinic.

PATIENTS

A total of 193 men and women, aged 30 to 74 years.

INTERVENTION

Treatment with 1.0 and 2.0 g/d of elemental calcium vs placebo over a 4-month period for cholesterol determinations and 6 months for blood pressure.

MAIN OUTCOME MEASURES

Serum total cholesterol and HDL-C levels, systolic and diastolic blood pressure.

RESULTS

Because there were no apparent differences in responses between the 1.0-g and 2.0-g calcium groups, their data were combined and compared with those of the placebo group. Among all participants, the mean total cholesterol level dropped 0.07 mmol/L (2.9 mg/dL) (1.3%) (P = .43) more, and the mean HDL-C level dropped 0.01 mmol/L (0.4 mg/dL) (1.1%) (P = .71) less in the calcium group than in the placebo group. Among participants without a history of hypercholesterolemia, the mean total cholesterol level dropped 0.18 mmol/L (6.8 mg/dL) (3.3%) (P = .10) and the HDL-C level dropped 0.02 mmol/L (0.6 mg/dL) (1.5%) (P = .61) more in the calcium group than in the placebo group. Among all participants, there was no apparent change in blood pressure until 6 months, when the mean systolic blood pressure dropped 0.8 mm Hg (0.6%) (P = .85) and the mean diastolic blood pressure dropped 0.4 mm Hg (0.5%) (P = .80) more in the calcium group than in the placebo group.

CONCLUSIONS

There were no substantial or statistically significant effects of calcium supplementation on total cholesterol or HDL-C levels or on blood pressure. There was a suggestion (not statistically significant) of a 0.07 to 0.18 mmol/L (3-7 mg/dL) or 2% to 4% drop in the total cholesterol level, a finding similar to that reported in other studies, which indicates the need for further study.

[Advances in endoscopic therapies for cancers of the digestive tract]

Endoscopic therapies for the treatment of cancers of the digestive tract have been improved. Today, some early cancers can be curatively treated by endoscopy (endoscopic polypectomy, endoscopic mucosal resection, heatprobe method, etc.). In addition, endoscopic local injection chemotherapy is performed for some advanced cancers as an adjuvant therapy. Recent progress in endoscopic therapies for cancer is reviewed in this paper, including their historical background. Improvements in these endoscopic treatment methods are expected to provide increased advantages for the treatment of patients with cancer in the near future.

The small polyp at flexible sigmoidoscopy: an historical perspective on why practices still vary

Current practices vary regarding the approach to small polyps discovered during screening flexible sigmoidoscopy. The most common practice is to perform colonoscopy whenever any adenoma is detected, a strategy that generally uses biopsy of polyps < or = 5 mm in size. However, data suggest that tubular adenomas < 1 cm in size in the distal colon have less predictive value than other distal adenomas for advanced adenomas in the proximal colon. Thus, some centers reserve colonoscopy for distal adenomas with tubulovillous or villous histology, > 1 cm in size, or with high-grade dysplasia. At the other end of the spectrum, another school of thought advocates screening colonoscopy, recognizing that most patients with advanced proximal adenomas do not have polyps in their distal colon. Advocates of this approach use any excuse to perform colonoscopy, whether it be a positive fecal occult blood test, minor symptoms, or small polyp at flexible sigmoidoscopy, even if hyperplastic. This review describes the history of the controversy regarding management of findings at flexible sigmoidoscopy, the data pertinent to the controversy, and the basis for the three approaches described above, all of which are currently within the standard of medical care.

[Streptococcus bovis endocarditis and colonic involvement]

McNeal and Blevins published the first report of Streptococcus bovis infective endocarditis in 1945. In 1951, McCoy suggested, for the first time, that an association could exist between Group D Streptococcus infective endocarditis and colon carcinoma; this association would be demonstrated later (1977) by Klein and unquestionably confirmed by several posterior works. Due to a clinical case of Streptococcus bovis infective endocarditis, which we had the opportunity of diagnosing, a review is made of the existent literature about the association between infection by this agent and the presence of lesions in the colon. Some recommendations are made in what respects the diagnosis and evaluation of patients with Streptococcus bovis infective endocarditis. Finally, the implications and therapeutic strategies in these patients are discussed.