Management of colorectal polyps

Prevalence of diverse colorectal polyps and risk factors for colorectal carcinoma in situ and neoplastic polyps

BACKGROUND

Most colorectal cancers originate from precancerous polyps. This study aimed to determine the prevalence of colorectal polyps with diverse pathological morphologies and to explore the risk factors for colorectal carcinoma in situ (CCS) and neoplastic polyps.

METHODS

Inpatients admitted from January 2018 to May 2023 were screened through the hospital information system. Polyps were classified according to pathological morphology. The prevalence of polyps was described by frequency and 95% confidence interval. Univariate and multivariate logistic regression analyses were used to explore the risk factors for CCS and neoplastic polyps.

RESULTS

In total, 2329 individuals with 3550 polyps were recruited. Among all patients, 76.99% had neoplastic polyps and 44.31% had advanced adenomas. Tubular adenoma had the highest prevalence at 60.15%, and the prevalence of CCS was 3.86%. Patients with a colorectal polyp diameter ≥ 1.0 cm or number ≥ 3 were 8.07 times or 1.98 times more likely to develop CCS than were those with a diameter < 1.0 cm or number < 3, respectively (OR 8.07, 95%CI 4.48-14.55, p < 0.0001; and OR 1.98, 95%CI 1.27-3.09, p = 0.002). The risk of CCS with schistosome egg deposition was also significantly increased (OR 2.70, 95%CI 1.05-6.98). The higher the levels of carbohydrate antigen (CA) 724 (OR 1.01, 95%CI 1.00-1.02) and CA211 (OR 1.16, 95%CI 1.03-1.32) in patients with colorectal polyps were, the greater the risk of CCS. When colorectal neoplastic polyps were analyzed, we discovered that for each 1-year increase in age, the risk of neoplastic polyps increased by 3% (OR 1.03, 95%CI 1.02-1.04), p < 0.0001. Patients with a polyp diameter ≥ 1.0 cm had a 2.11-fold greater risk of neoplastic polyps compared to diameter < 1.0 cm patients (OR 3.11, 95%CI 2.48-3.92), p < 0.0001. In addition, multiple polyps and CA199 levels are risk factors for neoplastic polyps.

CONCLUSION

More than 3/4 of colorectal polyp patients have neoplastic polyps. Patients are more inclined to develop CCS and neoplastic polyps if they have large polyps (> 1.0 cm) or multifocal polyps. The levels of the tumor markers CA724 and CA211 show some potential usefulness for predicting CCS and may be exploited for early identification of high-risk populations.

Prevalence of incidental colorectal cancer and polyps in autopsies of different populations: a systematic review with meta-regression analysis

The colorectal cancer (CRC) and polyps incidentally found in autopsies represent the lesions that have not actually caused problems throughout the lifetime and thus may not need to be removed during screening. This study aimed to investigate the prevalence of incidental CRC (iCRC) and polyps in autopsies of different populations. A systematic search was performed on 19 August 2022 to identify autopsy studies that provided data on prevalence of iCRC, adenomatous polyps, hyperplastic polyps, and/or all polyps combined. The prevalence was pooled with the random-effects model. Subgroup and multivariable meta-regression analyses were conducted to investigate the heterogeneity. Forty-three eligible studies including 59,656 autopsies were identified, with 94% conducted before 1990 when CRC screening was uncommon or not available. The pooled prevalence was 0.7% (95% confidence interval [CI], 0.3-1.2%) for iCRC, 18.4% (95% CI, 13.3-24.1%) for adenomatous polyps, 16.4% (95% CI, 8.7-25.9%) for hyperplastic polyps, 26.3% (95% CI, 15.4-38.8%) for all polyps combined, and 29.9% (95% CI, 14.8-47.6%) for iCRC plus polyps. The prevalence of iCRC was higher (1.2%) in white-predominant populations but lower (0.4%) after excluding low-quality studies. Multivariable analyses showed that the prevalence of polyps was higher in white-predominant populations and higher-quality studies, increased with age, and showed a downward trend from "before 1975" through "after 1985". In conclusion, the prevalence of iCRC in autopsies was not low, considering the average lifetime risk of CRC, while incidental polyps were common. Both varied greatly in different populations. These findings may have implications when weighing the benefits and harms of screening.

Do surface morphology and pit pattern have a role in predicting cancer for colon polyps in North America?

BACKGROUND

The surface morphology of colorectal polyps is well correlated with submucosal invasion in Eastern Countries but not in North America. We aimed to investigate associations between the Paris classification, surface morphology, and Kudo pit pattern to submucosal invasion in advanced endoscopic resection techniques.

METHODS

We retrospectively analyzed prospectively collected data of consecutive advanced endoscopic procedures conducted by a single surgeon between August 2017 and October 2018. The data included patients' demographics, the endoscopic finding of polyps (Paris, Kudo, and surface morphology), and pathology results.

RESULTS

The study consisted of 138 lesions, and the mean age was 67 ± 10 years. The most common polyp locations were cecum (n = 41, 30%) followed by ascending colon (n = 28, 20%), and sigmoid colon (n = 18, 13%).The median polyp size was 30 mm (25-40). The en-bloc resection rate was 96%, and 11 (8%) polyps had adenocarcinoma with submucosal invasion. Nine patients (6.5%) had late bleeding, and 3 (2.2%) perforation occurred. Polyps with pit pattern of Kudo IV (n = 4, 36.4%) and Kudo V (n = 6, 54.5%) were associated with submucosal invasion.

CONCLUSIONS

Surface morphology and pit pattern can predict submucosal invasion in the North American patient population. Polyp morphology may aid polyp selection for advanced endoscopic interventions.

Comparison of Concordance of Peptic Ulcer Disease, Non-Adenomatous Intestinal Polyp, and Gallstone Disease in Korean Monozygotic and Dizygotic Twins: A Cross-Sectional Study

Epidemiological studies have suggested the role of multiple genetic and environmental factors in the development of non-neoplastic gastrointestinal (GI) diseases; however, little information is available on these factors in the Korean population. Therefore, this cross-sectional study explored the effect of these factors by analyzing the concordance of several benign GI disorders in 525 monozygotic twins compared to that in 122 dizygotic twins aged >20 years from the Healthy Twin Study data of the Korean Genome and Epidemiology Study (2005-2014). Chi-square test, Wilcoxon rank-sum, and binomial and multinomial logistic regression models were used for statistical analysis. There was lack of concordance of gastric/duodenal ulcers and cholelithiasis/cholangitis between monozygotic twins compared to that in dizygotic twins, suggesting that environmental factors may mediate those concordant disease expressions in monozygotic twins. The concordance of intestinal polyps in monozygotic twins was 32% lower than that in dizygotic twins (p = 0.028), indicating that the effect of genetic factors on the risk for intestinal polyp development may be low. In conclusion, the lack or low concordance of several benign GI diseases between monozygotic and dizygotic twin groups suggests the relative importance of environmental factors, indicating that these are preventable diseases.

Quantification of fibrinogen-to-pre-albumin ratio provides an integrating parameter for differential diagnosis and risk stratification of early-stage colorectal cancer

Background

Circulating fibrinogen to pre-albumin ratio (FPR) and albumin to fibrinogen ratio (AFR) are effective factors for predicting the prognosis of colorectal cancer (CRC). However, the role of these two ratios in diagnosing early-stage CRC and identifying the stage II CRC subgroup with high relapse risk remains unknown. This study aimed to assess the potential of FPR and AFR in differential diagnosis and risk stratification of early-stage CRC.

Methods

A discovery (694 and 512 patients with benign colorectal polyps and stage I–II CRC, respectively) and validation (201 benign colorectal polyps cases and 202 stage I–II CRC individuals) cohorts were enrolled in this study. Receiver operating characteristic curve (ROC), Kaplan–Meier curve, and time-dependent ROC were used to evaluate the diagnostic efficacy of AFR and FPR in the two cohorts and overall population, and the discriminating role of FPR in identifying clinical high-relapse risk patients in comparison with common clinical characteristics in stage II CRC patients.

Results

The area under the curve (AUC) of the preoperative circulating FPR was higher than that of AFR in the diagnosis of stage I–II CRC from colorectal adenomas and benign colorectal polyps in the discovery and validation cohorts and overall population. Carcinoembryonic antigen (CEA) combined with FPR could effectively discriminate early-stage CRC from colorectal adenomas or benign polyps. Preoperative FPR could effectively distinguish stage II subgroups with high and low relapse risk. It was superior to common clinical characteristics in identifying high-risk surgical patients who could benefit from adjuvant chemotherapy (CT) [time-dependent AUC: 0.637 vs. 0.511, p < 0.001 for predicting recurrence-free survival (RFS); 0.719 vs. 0.501, p < 0.001 for predicting overall survival (OS)]. Furthermore, CT treated stage II patients with FPR > 20 had the highest recurrence (31.16%) and death rates (21.88%), with similar highest recurrence (30.70%) and death (26.82%) rates found in non-CT-treated patients with FPR > 20. Stage II CRC patients with 20 ≥ FPR > 15 could significantly benefit from postoperative CT, as the recurrence (33.30%) and death (35.71%) rates within non-CT treated patients were approximately five times higher than those of the CT-treated cases (6.77% and 7.41% for the recurrence and death rates, respectively). No significant difference in recurrence rate was observed between L-FPR (≤ 15) patients with (10.00%) or without CT (9.76%), indicating that these patients might not require to receive adjuvant CT after curative resection.

Conclusions

Preoperative FPR combined with CEA is superior to common tumor biomarkers, FPR, or AFR in distinguishing early-stage CRC from benign colorectal polyps. Circulating FPR can be an effective biomarker for identifying high-risk patients and choosing suitable therapeutics for early-stage CRC.

Risk Factors for High-Risk Adenoma on the First Lifetime Colonoscopy Using Decision Tree Method: A Cross-Sectional Study in 6,047 Asymptomatic Koreans

Background/Aims: As risk of colorectal neoplasm is varied even in persons with “average-risk,” risk evaluation and tailored screening are needed. This study aimed to evaluate the risk factors of high-risk adenoma (HRA) in healthy individuals and determine the characteristics of advanced neoplasia (AN) among individual polyps.

Methods: Asymptomatic adults who underwent the first lifetime screening colonoscopy at the Seoul National University Hospital Healthcare System Gangnam Center (SNUH GC) were recruited from 2004 to 2007 as SNUH GC Cohort and were followed for 10 years. Demographic and clinical characteristics were compared between the subjects with and without AN (≥10 mm in size, villous component, and/or high-grade dysplasia and/or cancer) or HRA (AN and/or 3 or more adenomas). For individual polyps, correlations between clinical or endoscopic features and histologic grades were evaluated using a decision tree method.

Results: A total of 6,047 subjects were included and 5,621 polyps were found in 2,604 (43%) subjects. Advanced age, male sex, and current smoking status were statistically significant with regards to AN and HRA. A lower incidence of AN was observed in subjects taking aspirin. In the decision tree model, the location, shape, and size of the polyp, and sex of the subject were key predictors of the pathologic type. A weak but significant association was observed between the prediction of the final tree and the histological grouping (Kendall's tau-c = 0.142, p < 0001).

Conclusions: Advanced neoplasia and HRA can be predicted using several individual characteristics and decision tree models.

Ileocecal Valve Sparing Resection for the Treatment of Benign Cecal Polyps Unsuitable for Polypectomy

Background:

Not all benign-appearance polyps are amenable to endoscopic removal and colectomy is required in some cases. This study aims to compare the early outcomes of cecal wedge resection with ileocecal valve sparring versus standard right colectomy in patients with endoscopically unresectable cecal polyps referred for surgery.

Methods:

From Apr 2010 to Aug 2019, all consecutive patients who underwent cecal wedge resection or right colectomy in ten European centers for a presumed endoscopically benign polyp unsuitable for endoscopic resection were retrospectively analyzed. The primary endpoint was morbidity. Secondary endpoints were operative time and length of hospital stay.

Results:

One hundred and ten patients were included: 25 patients underwent cecal wedge resection and 85 a right colectomy. There were 56 men (51%) and 90% of the procedures were performed laparoscopically. 29 lesions were located at the appendix orifice (26.4%). Mortality was nil. There were no significant differences between both procedures for morbidity rate (20% versus 24.7%) or reoperation (4% versus 4.7%). Cecal wedge was related to shorter operative time (63 min versus 150 min, P = .008) and shorter hospital stay (5 days versus 6 days, P = .049). Only 1 patient had a salvage right colectomy after cecal wedge for a pTis adenoma.

Conclusions:

For benign-appearance cecal polyps unsuitable for endoscopic ablation, cecal wedge resection is safe and should be considered as an attractive alternative to right colectomy.

Role of Endoscopic Resection Versus Surgical Resection in Management of Malignant Colon Polyps: a National Cancer Database Analysis

BACKGROUND

Endoscopic resection (polypectomy) or surgery, are the main approaches in management of malignant colon polyps. There are very few large population-based studies comparing outcomes between the two.

METHODS

Using the National Cancer Database, we identified patients ≥ 18 years with the first diagnosis of T1N0M0 malignant polyp from 2004 to 2015. Patients with a positive resection margin were excluded. Outcomes were compared between those who had surgery versus those who had polypectomy. Overall survival was compared using Kaplan-Meier curves. Multivariate Cox proportional hazards analysis was performed to generate hazard ratios, adjusted for patient, demographic, and tumor factors.

RESULTS

A total of 31,062 patients met the inclusion criteria, out of which 2593 (8.3%) underwent polypectomy alone and 28,469 (91.7%) had surgery. Overall survival was significantly better in the surgical group compared with the polypectomy group. One-year and 5-year survival for surgery were 95.8% and 86.1% respectively compared with 94.2% and 80.6% for polypectomy (p < .0001). Hazard ratio for surgery after adjusting for various clinical-, demographic-, and tumor-level factors was 0.53 (p < .0001).

CONCLUSION

Our study is the largest population-based analysis of patients with T1N0M0 malignant colon polyps. Overall survival was higher in patients who underwent surgery compared with polypectomy. This remained consistent even after adjusting for multiple patient and tumor factors between the two groups.

Revisiting the tumorigenesis timeline with a data-driven generative model

Recently, investigators have shown that only a few driver gene mutational events appear to be needed for cancer to occur. However, the reason that some mutational events precede others in the same cancer and the explanation for tissue-specific differences in this timing, remain mysterious. We here combine mathematical modeling with epidemiologic studies and sequencing data to address these questions. We suggest that the first driver event in cancers generally occurred at early ages and provide estimates for the fitness of different types of drivers during tumor evolution, showing how they vary with the tissue of origin.

Cancer is driven by the sequential accumulation of genetic and epigenetic changes in oncogenes and tumor suppressor genes. The timing of these events is not well understood. Moreover, it is currently unknown why the same driver gene change appears as an early event in some cancer types and as a later event, or not at all, in others. These questions have become even more topical with the recent progress brought by genome-wide sequencing studies of cancer. Focusing on mutational events, we provide a mathematical model of the full process of tumor evolution that includes different types of fitness advantages for driver genes and carrying-capacity considerations. The model is able to recapitulate a substantial proportion of the observed cancer incidence in several cancer types (colorectal, pancreatic, and leukemia) and inherited conditions (Lynch and familial adenomatous polyposis), by changing only 2 tissue-specific parameters: the number of stem cells in a tissue and its cell division frequency. The model sheds light on the evolutionary dynamics of cancer by suggesting a generalized early onset of tumorigenesis followed by slow mutational waves, in contrast to previous conclusions. Formulas and estimates are provided for the fitness increases induced by driver mutations, often much larger than previously described, and highly tissue dependent. Our results suggest a mechanistic explanation for why the selective fitness advantage introduced by specific driver genes is tissue dependent.

Management of Large Cecal Polyps: When Can the Ileocecal Valve Be Spared?

BACKGROUND

Endoscopic mucosal resection comprises the first-line treatment for large cecal polyps. With up to 14% of unresectable colonic polyps harboring malignancy, the management of endoscopically unresectable cecal polyps remains an oncologic right hemicolectomy, which can be associated with substantial postoperative morbidity.

OBJECTIVE

This study compares the outcomes of patients with cecal polyps who underwent either endoscopic mucosal resection, a cecectomy, or a right hemicolectomy.

DATA SOURCES

Patients undergoing either endoscopic mucosal resection, partial cecectomy, or right hemicolectomy from 2008 to 2017 at a single tertiary care institution were selected.

STUDY SELECTION

This was a retrospective cohort study.

MAIN OUTCOME MEASURES

The primary outcomes measured were the rate of malignancy, complication rate, estimated blood loss, and hospital length of stay between surgical cohorts.

RESULTS

One hundred twenty-nine patients with cecal polyps were identified, of which 52 were referred for surgery. Nineteen underwent partial cecectomy and 33 (27.3%) underwent right hemicolectomy. Two patients undergoing cecectomy required conversion to hemicolectomy because the resected specimen did not contain the polyp. The 2 surgical cohorts did not differ significantly regarding age, sex, or ASA classification. Procedural complication rates were higher among those undergoing hemicolectomy compared with those undergoing cecectomy (37.1% versus 5.9%, p = 0.02). Estimated blood loss (50 vs 10 mL, p = 0.02), operative duration (98 vs 76 minutes, p = 0.009), and length of stay (4 vs 2 days, p < 0.001) were higher in patients undergoing hemicolectomy than in those undergoing cecectomy. No invasive malignancies were identified on final pathology within the cecectomy cohort.

LIMITATIONS

Single-institution data and retrospective design were limitations of this study.

CONCLUSIONS

In tertiary centers, the majority of large cecal polyps are benign and can be addressed by using endoscopic mucosal resection. When involvement of the appendiceal orifice or ileocecal valve precludes endoscopic treatment, surgical resection is the standard of care. In the subset of cases not involving the ileocecal valve and without preoperative evidence of malignancy, partial cecectomy spares the ileocecal valve and can offer reduced postoperative morbidity compared with a formal right hemicolectomy. See Video Abstract at http://links.lww.com/DCR/A674.

Molecular characterization of colorectal adenomas with and without malignancy reveals distinguishing genome, transcriptome and methylome alterations

The majority of colorectal cancer (CRC) arises from precursor lesions known as polyps. The molecular determinants that distinguish benign from malignant polyps remain unclear. To molecularly characterize polyps, we utilized Cancer Adjacent Polyp (CAP) and Cancer Free Polyp (CFP) patients. CAPs had tissues from the residual polyp of origin and contiguous cancer; CFPs had polyp tissues matched to CAPs based on polyp size, histology and dysplasia. To determine whether molecular features distinguish CAPs and CFPs, we conducted Whole Genome Sequencing, RNA-seq, and RRBS on over 90 tissues from 31 patients. CAPs had significantly more mutations, altered expression and hypermethylation compared to CFPs. APC was significantly mutated in both polyp groups, but mutations in TP53, FBXW7, PIK3CA, KIAA1804 and SMAD2 were exclusive to CAPs. We found significant expression changes between CAPs and CFPs in GREM1, IGF2, CTGF, and PLAU, and both expression and methylation alterations in FES and HES1. Integrative analyses revealed 124 genes with alterations in at least two platforms, and ERBB3 and E2F8 showed aberrations specific to CAPs across all platforms. These findings provide a resource of molecular distinctions between polyps with and without cancer, which have the potential to enhance the diagnosis, risk assessment and management of polyps.

Cost Effectiveness of Colorectal Cancer Screening Interventions with Their Effects on Health Disparity Being Considered

Purpose

The purpose of this study was to evaluate the cost effectiveness of colorectal cancer screening interventions with their effects on health disparity being considered.

Materials and Methods

Markov cohort simulation was conducted with the cycle/duration of 1/40 year(s). Data came from the results of randomized trials and others. Participants were hypothetical cohorts aged 50 years as of year 2013 in 16 Korean provinces. The interventions until the age of 80 were annual organized fecal occult blood test (FOBT) (standard screening), annual FOBT with basic reminders for provinces with higher mortalities than the national average (targeted reminder) and annual FOBT with basic/enhanced reminders for all provinces (universal reminder 1 and 2). The comparison was non-screening, the outcome was quality-adjusted life years, and only medical costs for screening and treatment were considered from a societal perspective. The Atkinson incremental cost effectiveness ratio (Atkinson ICER), the incremental cost effectiveness ratio adjusted by the Atkinson Inequality Index, was used to evaluate the cost effectiveness of the four interventions with their impacts on regional health disparity being considered.

Results

Health disparity was smallest (or greatest) in non-screening (or the standard screening). The targeted reminder had smaller health disparity, and smaller Atkinson ICER with respect to standard screening, than did the universal reminder 1 and 2.

Conclusion

The targeted reminder might be more cost effective than the universal reminders with their effects on health disparity being considered. This study helps to develop promotional effort for colorectal cancer screening with both the greatest cost effectiveness and the smallest health disparity

Management of Malignant Adenomas

Most polyps that originate in the colon and rectum are benign. A small subset of polyps will contain a malignancy. Although most malignant adenomas are managed with colonic resection a number can be approached with endoscopic, minimally invasive, and observational techniques. This article reviews the histologic characteristics and adverse risk factors that would portend a poor oncologic outcome and therefore suggest formal colonic resection. Modern endoscopic techniques such as endoscopic mucosal resection and endoscopic submucosal resection are discussed.

Influence of patient age and colorectal polyp size on histopathology findings

Background

Colorectal cancer is a major cause of morbidity and mortality and can arise through the adenoma-carcinoma sequence. Colonoscopy is considered the method of choice for population-wide cancer screening.

Aim

To assess the characteristics of endoscopically resected polyps in a consecutive series of patients who underwent colonoscopy at a university hospital and compare histopathology findings according to patient age and polyp size.

Methods

Retrospective, cross-sectional of 1950 colonoscopy reports from consecutively examined patients. The sample was restricted to reports that mentioned colorectal polyps. A chart review was carried out for collection of demographic data and histopathology results. Data were compared for polyps sized ≤0.5 cm and ≥0.6 cm and then for polyps sized ≤1.0 cm and ≥1.1 cm. Finally, all polyps resected from patients aged 49 years or younger were compared with those resected from patients aged 50 years or older.

Results

A total of 272 colorectal polyps were resected in 224 of the 1950 colonoscopies included in the sample (11.5%). Polyps >1 cm tended to be pedunculated (p=0.000) and were more likely to exhibit an adenomatous component (p=0.001), a villous component (p=0.000), and dysplasia (p=0.003). These findings held true when the size cutoff was set at 0.5 cm. Patients aged 50 years or older were more likely to have sessile polyps (p=0.023) and polyps located in the proximal colon (p=0.009). There were no significant differences between groups in histopathology or presence of dysplasia.

Conclusion

Polyp size is associated with presence of adenomas, a villous component, and dysplasia, whereas patient age is more frequently associated with sessile polyps in the proximal colon.

Correlation between incidental FDG PET/CT colorectal observations and endoscopic and histopathological results

Fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) is used in the imaging workup of various malignancies. Incidental gastrointestinal observations on FDG PET/CT may be of clinical significance. The aim of the present study was to evaluate endoscopic and histopathological observations in patients referred for colonoscopy due to incidental FDG colonic uptake on a PET/CT study. Fifty-six patients with incidental colonic findings on FDG PET/CT underwent colonoscopy. Normal colonoscopies were observed in 63% of the patients. In 37% of the colonoscopies, we identified an endoscopic observation, including 67% with benign adenomatous polyps, 3% with hyperplastic polyps, 20% with advanced histological lesions and 10% with a malignancy.

Trends, patterns, and outcomes in the management of malignant colonic polyps in the general population of the United States

BACKGROUND

Colonoscopic screening has increased detection of malignant colonic polyps (MPs). The goal of this study was to analyze trends and patterns in the surgical treatment of MPs and to assess outcomes as measured by lymph node retrieval and patient survival.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) registry was queried to identify 19,743 patients with MPs from 1988 to 2003.

RESULTS

The majority of MPs were present in the sigmoid and descending colon (54%), and 38% were tubular, 40% were tubulovillous, and 22% were villous. During the study period, the incidence of MPs increased from 29% to 42% and surgical resection (SR) was increasingly used for treatment, from 54% to 70%. Predictors of SR were aged <70 years (odds ratio [OR], 1.3; 95% confidence interval [95% CI], 1.2-1.4), high-grade tumors (OR, 1.5; 95% CI, 1.2-1.9), diagnosis in 1999 through 2003 (OR, 1.7; 95% CI, 1.5-1.9), villous subtype (OR, 2.3; 95% CI, 2.0-2.6), and right colon location (OR, 8.1; 95% CI, 7.0-9.4). In patients undergoing SR, the mean and median number of lymph nodes was only 4 and 1, respectively. A significant percentage of patients (49%) had no lymph nodes retrieved and a worse overall survival at 5 years compared with patients who had at least 1 lymph node examined (64% vs 74%; P <.001).

CONCLUSIONS

MPs appear to be increasing in incidence, and there is a trend toward increased use of SR for treatment. However, patients undergoing SR for MPs undergo suboptimal assessment of lymph nodes, with a detrimental impact on survival. Adequate lymphadenectomy and lymph node evaluation are crucial to improve outcomes in patients with these potentially curable lesions. Cancer 2011. © 2010 American Cancer Society.

Management of the malignant polyp

In the United States, the prevalence of adenomatous polyps found during colonoscopic evaluation ranges from 25 to 41%, and of these, 2 to 5% contain invasive malignancy. The management of the malignant polyp continues to be challenging. Endoscopic resection by polypectomy has been shown to be sufficient for management of certain polyps containing cancer; however, it is important to keep in mind that polypectomy does not remove the lymph node drainage basin and may be an inadequate resection for some adenocarcinoma containing polyps that have specific histologic features. Depth of invasion has been shown to correlate with the risk of lymph node metastasis. Other unfavorable histologic features include lymphovascular invasion, poor differentiation, inability to assess margin (piecemeal resection), and positive resection margin (< 2 mm); these are important factors to consider in management. For these patients formal oncologic surgical resection is indicated. Traditional open or laparoscopic procedures are routinely used for colectomy in these patients. Following polypectomy or segmental colectomy, surveillance of these patients is critical, and can lead to excellent long-term outcomes.

Suppressor of cytokine signaling-2 gene disruption promotes Apc(Min/+) tumorigenesis and activator protein-1 activation

Epigenetic in vitro and in vivo studies suggest that suppressor of cytokine signaling-2 (SOCS2) may normally limit tumorigenesis in the intestine; however, this theory has not been directly tested. We hypothesized that SOCS2 deficiency promotes spontaneous intestinal tumorigenesis in Apc(Min/+) mice. Therefore, we quantified tumor number, size, and load in the small intestine and colon using SOCS2(+/+)/Apc(Min/+), SOCS2(+/-)/Apc(Min/+), and SOCS2(-/-)/Apc(Min/+) mice and assayed hematocrit as an indirect marker of disease severity. Biochemical and histological assays were used to assess mechanisms. Heterozygous and homozygous disruption of SOCS2 alleles promoted 166 and 441% increases in tumor load in the small intestine, respectively, accelerated development of colon tumors, and caused severe anemia. SOCS2 deletion promoted significant increases in intestinal insulin-like growth factor-I mRNA but did not affect plasma insulin-like growth factor-I. Western blots and immunohistochemical analysis demonstrated that tumor and nontumor intestinal tissue of SOCS2(-/-)/Apc(Min/+) mice had increased serine 727 phosphorylation of signal transducer and activator of transcription 3 compared with SOCS2(+/+)/Apc(Min/+) mice. Moreover, electromobility shift assays showed that SOCS2 deletion did not alter signal transducer and activator of transcription 3 DNA binding. However, tumors and small intestine from SOCS2(-/-)/Apc(Min/+) showed dramatic increases in activator protein-1 (AP-1) DNA binding, and SOCS2 overexpression in vitro reduced levels of AP-1. These studies indicate that SOCS2 deletion promotes the spontaneous development of intestinal tumors driven by mutations in the adenomatous polyposis coli/beta-catenin pathway and activates AP-1. Therefore, reduced expression or epigenetic silencing of SOCS2 may serve as a useful biomarker for colorectal cancer risk.

Automated measurement of colorectal polyp height at CT colonography: hyperplastic polyps are flatter than adenomatous polyps

OBJECTIVE

Hyperplastic polyps are more difficult to detect than adenomatous polyps at CT colonography (CTC), and it has been theorized that this difference in detectability is because hyperplastic polyps are flatter. Using automated software that computes polyp height, we determined whether hyperplastic colonic polyps on CTC are indeed flatter than adenomatous polyps of comparable width.

MATERIALS AND METHODS

At three medical centers, 1,186 patients underwent oral contrast-enhanced CTC and same-day optical colonoscopy (OC) with segment unblinding for colorectal cancer screening. One hundred eighty-five of the patients had at least one hyperplastic or adenomatous polyp 6-10 mm visible at both OC and CTC, where size was determined by a calibrated guidewire at OC. To assess flatness, the heights of the polyps at CTC were measured using a validated automated software program. The heights and height-to-width ratios of the hyperplastic polyps were compared with those of the adenomatous polyps using a Student's t test (two-tailed, unpaired, unequal variance).

RESULTS

There were 176 adenomatous and 83 hyperplastic polyps visible at segment-unblinded OC. The fraction of these polyps that were measurable at CTC using the automated software was not significantly different for adenomatous versus hyperplastic polyps (158/176 [89.8%] vs 73/87 [83.9%], respectively; p = 0.2). The average height-to-width ratios using automated width measurements were 15% less for hyperplastic polyps: 0.39 +/- 0.20 (n = 158) and 0.33 +/- 0.19 (n = 73) for adenomatous and hyperplastic polyps, respectively (p = 0.03). When polyps of comparable OC size or CTC width were considered, the heights of hyperplastic polyps were up to 27% less than those of adenomatous polyps.

CONCLUSION

For 6-10 mm polyps of a given size as determined by OC or a given width at CTC, hyperplastic polyps tend to be flatter (i.e., have lower height) compared with adenomatous polyps.

Epidemiology and management options for colorectal cancer in children

Colorectal carcinoma (CRC), although primarily a disease of adulthood, accounts for 2% of malignancies in adolescents and has been reported in children as young as 9 months of age. Our knowledge of CRC in pediatrics is based on a handful of case series and case reports. Apart from one small clinical trial, there has been a lack of prospective clinical studies in this age group. Based on these published reports, most CRC in children is sporadic, but it can also arise in the setting of predisposing conditions, such as gastrointestinal polyposis syndromes, nonpolyposis familial cancer syndromes, and inflammatory bowel disease. Despite some similarities to adult disease, CRC in childhood may be intrinsically different biologically, because it differs from adult-onset CRC in several respects. Childhood CRC tends to be diagnosed at an advanced stage, is largely of mucinous histology, and (probably because of these features) tends to have a poorer outcome. As a result of its rarity in children and the lack of prospective pediatric studies, recommendations for therapy are primarily extrapolated from adult clinical trials. A review of pediatric case series in the English literature emphasizes the prognostic significance of stage of disease, as well as extent of surgical resection. As in adults, early detection is critical in an effort to capture the disease at less advanced stages. Complete surgical resection with aggressive lymph node dissection is essential for cure, and neoadjuvant chemotherapy may be used in an effort to render unresectable lesions resectable. Active agents in adults with CRC include fluorouracil, folinic acid (leucovorin), oxaliplatin, and irinotecan. Furthermore, newer targeted therapeutic agents, such as bevacizumab and cetuximab, have added additional efficacy to the standard chemotherapy backbone. Collaborative multi-institutional pediatric clinical trials are needed to evaluate the prognosis, optimal treatment response, and the basic biology of childhood onset CRC.

Retrieval of colorectal polyps following snare polypectomy: Experience of the multiple-suction technique in 602 cases

BACKGROUND

Retrieving colorectal polyp after endoscopic snare polypectomy is time consuming and possibly incurs a failure. The aim of the study was to assess the effectiveness of the multiple-suction (M-S) technique for retrieving a variety of polyps.

MATERIALS AND METHODS

Four hundred and nine cases received endoscopic snare polypectomy from January 2003 to January 2007 were reviewed. The resected polyps were retrieved by M-S technique, in which suction regarded as the leading technique, was taken in combination with channel occlusion, trap, snare, and grasping forcep. Time of cecal intubation and of polypectomy, total examination time, shape, size, location, and number of polyp(s) were recorded. Retrieval time and polyp lost rate were also noted.

RESULTS

A total of 602 polyps more than 3 mm in diameter underwent snare polypectomy. There were 96.7% (582/602) of polyps retrieved by the M-S technique. The mean retrieval time was 1.5 +/- 0.6 min. Time of polypectomy, retrieval time, and total examination time were significantly positive correlative with the number of polyps (P < 0.05). In a univariate analysis, longer retrieval time was significantly associated with larger polyps, more distant polyps from the anus, and a greater number of polyps, while higher polyp lost rate was significantly associated with sessile polyp, smaller polyps, and a greater number of polyps. In a multivariate analysis, retrieval time level (< or = 2.0 or >2.0 min) was linked to the number of polyps.

CONCLUSIONS

The M-S technique is proved to be reliable when used in the majority cases of colorectal polyp retrieval. In retrieving too many polyps, the M-S technique is time consuming, and hence, additional methods should be applied to improve its retrieval effectiveness.

The colorectal adenoma-carcinoma sequence

BACKGROUND

It is widely accepted that the adenoma-carcinoma sequence represents the process by which most, if not all, colorectal cancers arise. The evidence supporting this hypothesis has increased rapidly in recent years and the purpose of this article is to review this evidence critically and highlight its clinical significance.

METHODS

Medline searches were used to identify recent key articles relating to the adenoma-carcinoma sequence. Further pertinent articles were obtained by manual scanning of the reference lists of identified papers.

RESULTS

The evidence supporting the adenoma-carcinoma sequence can be classified as epidemiological, clinicopathological and genetic. The most recent and largest body of data relates to molecular genetic events and their cellular effects; however, many other approaches, such as cytogenetics, molecular cytogenetics and cytometry, have also yielded valuable information.

CONCLUSION

Recent work continues to support the adenoma-carcinoma sequence, but there is a paucity of data on the interrelationship between different genetic mutations and on the relationship between molecular and other types of genetic abnormalities. The clinical utility of the observations described has yet to be fully realized and global genetic analysis of colorectal tumours may prove to be central in rational adenoma management.

Changing concepts of dietary fiber: implications for carcinogenesis

The dietary fiber (DF) hypothesis suggested that DF, as plant cell walls, protected against colorectal cancer. The implicit assumption in much historic literature was that the readily analyzed and quantified nonstarch polysaccharide (NSP) component was critical in cancer protection. However, the presence of polymeric phenolic components such as lignin or suberin has profound effects on the physicochemical properties of the cell walls and largely determines their physiological properties in humans. In certain groups of food plants, degradation of cell walls that contain neither lignin nor suberin releases ferulic acid and other hydroxycinnamic acids. These acids have antioxidant, antimutagenic, and other anticancer effects, including modulation of gene expression and immune response. Reexamination of literature on cancer protection suggests that plant cell walls containing significant amounts of phenolic components may be the most likely to protect against cancer. In the last 30 years, the definition of DF has been incrementally expanded to incorporate NSP extracted from plant cell walls and from sources other than plant cell walls, then resistant starch, and most recently nondigestible oligosaccharides. On the early definitions, increased consumption of DF could only be achieved by increasing the intake of whole grains, brans, or other food plant material that would increase the intake of plant cell walls containing significant amounts of phenolic components. However, the new definitions make it possible to increase "dietary fiber" without consuming any such materials. We suggest that this could have negative connotations for cancer risk in human populations.

Introduction to colorectal cancer

OBJECTIVES

To provide an overview of colorectal carcinoma (CRC), including current treatment strategies for various stages of the disease.

DATA SOURCES

Research articles and textbooks.

CONCLUSIONS

Despite screening methods for early detection of CRC, many patients present with late-stage disease and have a poor prognosis. The approval of irinotecan for CRC changed the approach to treatment, and there are numerous agents under clinical evaluation that may soon be available for the management of patients with CRC.

IMPLICATIONS FOR NURSING PRACTICE

Recent advances in molecular targeting have led to the development of new treatments for CRC. Because nurses will ultimately administer these agents, it is important to understand how these agents target CRC.

Acromegaly and the risk of cancer

Recent studies suggest that acromegaly might predispose to an increased risk of benign and malignant neoplasms, thus influencing the final outcome of the disease. The exact mechanism of neoplastic events in acromegaly has not been completely clarified. Several studies indicate an autocrine-paracrine role for growth hormone (GH) and insulin-like growth factor-I (IGF-I) in the proliferation of normal and neoplastic cells. The paper reviews the results of molecular, clinical and epidemiological data supporting a role for GH-IGF-I action in colon, prostate, breast and lung carcinogenesis inpatients with acromegaly.

Colorectal cancer in Russian-speaking Jewish emigrés: community-based screening

OBJECTIVES

Colorectal cancer (CRC) screening by fecal occult blood testing and flexible sigmoidoscopy is recommended by many authorities for those older than age 50. Ashkenazi Jews have been shown to have a higher level of CRC and polyps than the general population. A subset of Ashkenazi Jews, Russian-speaking Jewish immigrants to the United States (RJIs), have not been studied extensively for CRC and may have additional risk factors not found in other Ashkenazi populations.

METHODS

A retrospective chart review was undertaken of fecal occult blood tests, endoscopy reports, and pathology reports of 132 RJIs and 124 non-RJI controls over age 50 between 1987 and 1999 at the Jewish Hospital of Cincinnati Medical Outpatient Clinic.

RESULTS

Mean ages at the time of diagnosis or flexible sigmoidoscopy were 68 yr for RJIs and 66 yr for the non-RJI patients. Of the RJI patients, 38.7% had positive findings: 37 (28.0%) with lesions < 2 cm, five (3.8%) with lesions > 2 cm, and nine (6.8%) with CRC. Of the non-RJI control group patients, 16.9% had positive findings: 16 (12.9%) with lesions < 2 cm, three (2.4%) with lesions > 2 cm, and two (1.6%) with CRC. Age- and sex-matched statistical analysis revealed significantly greater CRC and significantly more polyps > 2 cm for the RJI patients (p < 0.003). This is higher than in other studies of Ashkenazis, which show a 2.3% incidence, and in statistics from the National Cancer Institute, which reveal a national CRC incidence rate for those over age 65 to be 0.30%.

CONCLUSIONS

RJIs in our study have polyps > 2 cm and CRC at a rate of 10.6%, as compared with 4.0% for in-clinic controls and a national average of 0.30% for patients over age 65. This suggests a need for more aggressive screening of this patient population for CRC.

APACC, a French prospective study on aspirin efficacy in reducing colorectal adenoma recurrence: design and baseline findings

Colorectal cancer is the second most frequent cause of death from cancer in western countries. Many lines of evidence suggest that non-steroidal anti-inflammatory drugs (NSAIDs) may offer chemoprevention against colorectal cancer. A multicentre, double-blind, randomized, controlled trial is underway to determine the efficacy of regular aspirin intake (160 or 300 mg/day) in reducing colorectal adenoma recurrence. We now report the baseline characteristics of subjects enrolled into the trial.

RESULTS

A total of 618 polyps were excised from 274 patients at the baseline colonoscopy. Men had on average (+/-SD) 2.5 +/- 1.8 polyps per subject and women had 1.7 +/- 1.2. Ninety-one (33.7%) had three or more adenomas and 183 (67.8%) had more than one adenoma measuring 10 mm or more in diameter. The mean (+/-SD) age of the subjects was 57.7 (+/- 9.4) years. Sixty-seven (24.9%) reported that they had previously had adenoma(s), 95 (35.2%) reported a family history of colorectal cancer and 41 (15.2%) a family history of colorectal adenomas.

PERSPECTIVE

All subjects will undergo a one-year clearance colonoscopy by February 2001. Clinical, molecular biological and dietary data will enable us to investigate other factors influencing the recurrence of adenomas in this group of high-risk subjects.

Automated polyp detection at CT colonography: feasibility assessment in a human population

PURPOSE

To test the feasibility of and improve a computer algorithm to automatically detect colonic polyps in real human computed tomographic (CT) colonographic data sets.

MATERIALS AND METHODS

Twenty patients with known polyps underwent CT colonography in the supine position. CT colonographic data were processed by using a shape-based algorithm that depicts masses that protrude into the lumen. We studied nine shape criteria and three isosurface threshold settings. Results were compared with those of conventional colonoscopy performed the same day.

RESULTS

There were 50 polyps (28 were > or =10 mm in size; 12, 5-9 mm; 10, <5 mm). The sensitivity with optimal settings for detecting polyps 10 mm or greater was 64% (18 of 28). Sensitivity improved to 71% (10 of 14) for polyps 10 mm or greater in well-distended colonic segments. Performance decreased for polyps less than 10 mm, poorly distended colonic segments, and other shape algorithms. There was a mean of six false-positive lesion sites per colon. These sites were reduced 39% to 3.5 per colon by sampling CT attenuation at the lesion site and discarding sites having attenuation less than a threshold.

CONCLUSION

Automated detection of colonic polyps, especially clinically important large polyps, is feasible. Colonic distention is an important determinant of sensitivity. Further increases in sensitivity may be achieved by adding prone CT colonography.