Bariatric Surgery Is Associated with a Recent Temporal Increase in Colorectal Cancer Resections, Most Pronounced in Adults Below 50 Years of Age

BACKGROUND

Colorectal cancer incidence is rising in adults < 50 years old, possibly due to obesity. Having bariatric surgery (BRS) should hypothetically reduce this trend, but data are limited. This study compared trends of colorectal cancer (CRC) versus other obesity-related gastrointestinal cancers (OGCs) between morbidly obese and post-BRS subjects.

MATERIAL AND METHODS

This retrospective cohort study investigated OGC resection trends using the 2006-2013 National Inpatient Sample. Patients with prior BRS and non-BRS controls with body mass index ≥ 40 kg/m² were included (n = 30,279 total). We divided OGCs into CRC and non-CRC OGCs (esophageal, stomach, liver, gallbladder, and pancreas). We calculated OGC resection trends in patients < 50 and ≥ 50 years old using the average annual percent change (AAPC).

RESULTS

BRS patients with OGCs were younger (59.3 vs 62.3 years old), with more female gender (77.4% vs 57.1%) and White race (72.6% vs 67%) compared with controls (p < 0.05). The number of CRC resections increased across all ages in 2006-2013, especially rectal cancer for BRS patients (AAPC + 19.8%, p = 0.04). The steepest rise in early-onset CRC resections was after BRS versus a lesser increase in morbid obesity controls (AAPC + 18.7% and + 13.7%, respectively, p < 0.001). In contrast, non-CRC OGCs increased in our controls but not post-BRS. In a sensitivity analysis, estimated CRC incidence trends also increased post-BRS despite adjusting for increasing BRS prevalence.

CONCLUSION

Our findings suggest that bariatric surgery is associated with a persistent increase in early-onset CRC trends. Studies are warranted to validate our results and test the impact of bariatric surgery on early-onset CRC biological mechanisms.

Risks of Colorectal Cancer and Cancer-Related Mortality in Familial Colorectal Cancer Type X and Lynch Syndrome Families

BACKGROUND

The risk of cancers is well characterized in Lynch syndrome (LS) families but has been less studied in familial colorectal cancer type X (FCCTX) families.

METHODS

In this article, we compare the risk estimates of first and second colorectal cancers (CRCs) in 168 FCTTX and 780 LS families recruited through the Colon Cancer Family Registry as well as the risk of cancer-related deaths and disease-free survival (DFS) after a first CRC. Our methodology is based on a survival analysis approach, developed specifically to model the occurrence of successive cancers (ie, first and second CRCs) in the presence of competing risk events (ie, death from any causes).

RESULTS

We found an excess risk of first and second CRC in individuals with LS compared to FCCTX family members. However, for an average age at first CRC of 60 years in FCCTX families and 50 years in LS families, the DFS rates were comparable in men but lower in women from FCCTX vs LS families, eg , 75.1% (95% confidence interval [CI] = 69.0% to 80.9%) vs 78.9% (95% CI = 76.3% to 81.3%) for the 10-year DFS. The 10-year risk of cancer-related death was higher in FCCTX families vs LS families, eg, 15.4% in men (95% CI = 10.9% to 19.8%) and 19.3% in women (95% CI = 13.6% to 24.7%) vs 8.9% (95% CI = 7.5% to 11.4%) and 8.7% (95% CI = 7.1% to 10.8%), respectively.

CONCLUSIONS

Individuals with CRCs arising in the context of FCCTX do not experience the same improved DFS and overall survival of those with LS, and that difference may be relevant in management decisions.

Trends in Incidence of Early-Onset Colorectal Cancer in the United States Among Those Approaching Screening Age

IMPORTANCE

Early-onset colorectal cancer incidence rates among patients aged 45 to 49 years have been considered much lower compared with the rates among patients aged 50 to 54 years, prompting debate about earlier screening benefits at 45 years. However, the observed incidence rates in the Surveillance, Epidemiology, and End Results (SEER) registries may underestimate colorectal cancer case burdens in those younger than 50 years compared with those older than 50 years because average-risk screening is generally not performed to detect preclinical cases of colorectal cancer. Finding steep incidence increases of invasive stage (beyond in situ) cases of colorectal cancer from age 49 to 50 years would be consistent with high rates of preexisting, undetected cancers in younger patients ultimately receiving a diagnosis of colorectal cancer after undergoing screening at 50 years.

OBJECTIVE

To assess the preclinical burden of colorectal cancer by analyzing its incidence in 1-year age increments, focusing on the transition between ages 49 and 50 years.

DESIGN, SETTING, AND PARTICIPANTS

Data from the SEER 18 registries, representing 28% of the US population, were used to conduct a cross-sectional study of colorectal cancer incidence rates from January 1, 2000, to December 31, 2015, in 1-year age increments (ages 30-60 years) stratified by US region (South, West, Northeast, and Midwest), sex, race, disease stage, and tumor location. Statistical analysis was conducted from November 1, 2018, to December 15, 2019.

MAIN OUTCOMES AND MEASURES

Incidence rates of colorectal cancer.

RESULTS

A total of 170 434 cases of colorectal cancer were analyzed among 165 160 patients (92 247 men [55.9%]; mean [SD] age, 51.6 [6.7] years). Steep increases in the incidence of colorectal cancer in the SEER 18 registries were found from 49 to 50 years of age (46.1% increase: 34.9 [95% CI, 34.1-35.8] to 51.0 [95% CI, 50.0-52.1] per 100 000 population). Steep rate increases from 49 to 50 years of age were also seen in all US regions, men and women, white and black populations, and in colon and rectal cancers. The rate ratio incidence increase in the SEER 18 registries from 49 to 50 years of age (1.46 [95% CI, 1.43-1.51]) was significantly higher than earlier 1-year age transitions. Steep rate increases in the SEER 18 registries were found from 49 to 50 years of age in localized-stage (75.9% increase: 11.2 [95% CI, 10.7-11.7] to 19.7 [95% CI, 19.0-20.3] per 100 000) and regional-stage (30.3% increase: 13.2 [95% CI, 12.7-13.8] to 17.2 [95% CI, 16.7-17.8] per 100 000) colorectal cancers. A total of 8799 of the 9474 cases (92.9%) of colorectal cancer in the SEER 18 registries from 2000 to 2015 that were diagnosed among individuals aged 50 years were invasive.

CONCLUSIONS AND RELEVANCE

Steep incidence increases between 49 and 50 years of age are consistent with previously undetected colorectal cancers diagnosed via screening uptake at 50 years. These cancers are not reflected in observed rates of colorectal cancer in the SEER registries among individuals younger than 50 years. Hence, using observed incidence rates from 45 to 49 years of age alone to assess potential outcomes of earlier screening may underestimate cancer prevention benefits.

Barriers to Lynch Syndrome Testing and Preoperative Result Availability in Early-onset Colorectal Cancer: A National Physician Survey Study

Objective

Although widely recommended, Lynch syndrome (LS) testing with tumor microsatellite instability (MSI) and/or immunohistochemistry (IHC) is infrequently performed in early-onset colorectal cancer (CRC), and CRC generally. Reasons are poorly understood. Hence, we conducted a national survey focusing on gastroenterologists, as they are frequently first to diagnose CRC, assessing testing barriers and which specialist is felt responsible for ordering MSI/IHC. Additionally, we assessed factors influencing timing of MSI/IHC ordering; testing on colonoscopy biopsy, opposed to post-operative surgical specimens, assists decisions on preoperative germline genetic testing and extent of colonic resection (ECR).

Methods

A 21-question web-based survey was distributed through an American College of Gastroenterology email listing.

Results

In total 509 completed the survey. 442 confirmed gastroenterologists were analyzed. Only 33.4% felt gastroenterologists were responsible for MSI/IHC ordering; pathologists were believed most responsible (38.6%). Cost, unfamiliarity interpreting results and unavailable genetic counseling most commonly prevented routine ordering (33.3%, 29.2%, 24.9%, respectively). In multivariable analysis, non-academic and rural settings were associated with cost and genetic counseling barriers. Only 46.1% felt MSI/IHC should always be performed on colonoscopy biopsy. Guideline familiarity predicted whether respondents felt surgical resection should be delayed until results returned given potential effect on ECR decisions.

Conclusion

Inconsistencies in who is felt should order MSI/IHC may lead to diffusion of responsibility, preventing consistent testing, including preoperatively. Assuring institutional universal testing protocols are in place, with focus on timing of testing, can optimize care. Strategies addressing cost barriers and genomic service availability in rural and non-academic settings can enhance testing. Greater emphasis on guideline familiarity is required.

Increased Risk of Colorectal Cancer Among Family Members of All Ages, Regardless of Age of Index Case at Diagnosis

BACKGROUND & AIMS

It is not clear whether familial risk of colorectal cancer (CRC) varies with age of index CRC patients or their relatives. We quantified the risk of CRC in first-degree relatives (FDRs), second-degree relatives, and first-cousin relatives of individuals with CRC, stratified by ages and sexes of index patients and ages of relatives.

METHODS

CRCs diagnosed between 1980 and 2010 were identified from the Utah Cancer Registry and linked to pedigrees from the Utah Population Database. Age- and sex-matched CRC-free individuals were selected to form the comparison group. CRC risk in relatives was determined by Cox regression analysis.

RESULTS

Of 18,208 index patients diagnosed with CRC, the highest familial risk was observed in FDRs of index CRC patients who were diagnosed at an age younger than 40 years (hazard ratio [HR], 2.53; 95% confidence interval [CI], 1.7-3.79). However, familial risk was increased in FDRs even when the index case was diagnosed with cancer at an advanced age (>80 years; HR, 1.76; 95% CI, 1.59-1.94). Ages of relatives and ages of index cases of CRC each affected familial cancer risk; the highest risk was found in young relatives (<50 years) of individuals with early-onset CRC (<40 years; HR, 7.0; 95% CI, 2.86-17.09).

CONCLUSIONS

All relatives of individuals with CRC are at increased risk for this cancer, regardless of the age of diagnosis of the index patient. Although risk is greatest among young relatives of early-onset CRC cases, relatives of patients diagnosed at advanced ages also have an increased risk.

Status of Competency-Based Medical Education in Endoscopy Training: A Nationwide Survey of US ACGME-Accredited Gastroenterology Training Programs

OBJECTIVES

The Accreditation Council for Graduate Medical Education (ACGME) emphasizes the importance of medical trainees meeting specific performance benchmarks and demonstrating readiness for unsupervised practice. The aim of this study was to examine the readiness of Gastroenterology (GI) fellowship programs for competency-based evaluation in endoscopic procedural training.

METHODS

ACGME-accredited GI program directors (PDs) and GI trainees nationwide completed an online survey of domains relevant to endoscopy training and competency assessment. Participants were queried about current methods and perceived quality of endoscopy training and assessment of competence. Participants were also queried about factors deemed important in endoscopy competence assessment. Five-point Likert items were analyzed as continuous variables by an independent t-test and χ(2)-test was used for comparison of proportions.

RESULTS

Survey response rate was 64% (94/148) for PDs and 47% (546/1,167) for trainees. Twenty-three percent of surveyed PDs reported that they do not have a formal endoscopy curriculum. PDs placed less importance (1—very important to 5—very unimportant) on endoscopy volume (1.57 vs. 1.18, P<0.001), adenoma detection rate (2.00 vs. 1.53, P<0.001), and withdrawal times (1.96 vs. 1.68, P=0.009) in determining endoscopy competence compared with trainees. A majority of PDs report that competence is assessed by procedure volume (85%) and teaching attending evaluations (96%). Only a minority of programs use skills assessment tools (30%) or specific quality metrics (28%). Specific competencies are mostly assessed by individual teaching attending feedback as opposed to official documentation or feedback from a PD. PDs rate the overall quality of their endoscopy training and assessment of competence as better than overall ratings by trainees.

CONCLUSIONS

Although the majority of PDs and trainees nationwide believe that measuring specific metrics is important in determining endoscopy competence, most programs still rely on procedure volume and subjective attending evaluations to determine overall competence. As medical training transitions from an apprenticeship model to competency-based education, there is a need for improved endoscopy curricula which are better suited to demonstrate readiness for unsupervised practice.

Multi-center colonoscopy quality measurement utilizing natural language processing

BACKGROUND

An accurate system for tracking of colonoscopy quality and surveillance intervals could improve the effectiveness and cost-effectiveness of colorectal cancer (CRC) screening and surveillance. The purpose of this study was to create and test such a system across multiple institutions utilizing natural language processing (NLP).

METHODS

From 42,569 colonoscopies with pathology records from 13 centers, we randomly sampled 750 paired reports. We trained (n=250) and tested (n=500) an NLP-based program with 19 measurements that encompass colonoscopy quality measures and surveillance interval determination, using blinded, paired, annotated expert manual review as the reference standard. The remaining 41,819 nonannotated documents were processed through the NLP system without manual review to assess performance consistency. The primary outcome was system accuracy across the 19 measures.

RESULTS

A total of 176 (23.5%) documents with 252 (1.8%) discrepant content points resulted from paired annotation. Error rate within the 500 test documents was 31.2% for NLP and 25.4% for the paired annotators (P=0.001). At the content point level within the test set, the error rate was 3.5% for NLP and 1.9% for the paired annotators (P=0.04). When eight vaguely worded documents were removed, 125 of 492 (25.4%) were incorrect by NLP and 104 of 492 (21.1%) by the initial annotator (P=0.07). Rates of pathologic findings calculated from NLP were similar to those calculated by annotation for the majority of measurements. Test set accuracy was 99.6% for CRC, 95% for advanced adenoma, 94.6% for nonadvanced adenoma, 99.8% for advanced sessile serrated polyps, 99.2% for nonadvanced sessile serrated polyps, 96.8% for large hyperplastic polyps, and 96.0% for small hyperplastic polyps. Lesion location showed high accuracy (87.0-99.8%). Accuracy for number of adenomas was 92%.

CONCLUSIONS

NLP can accurately report adenoma detection rate and the components for determining guideline-adherent colonoscopy surveillance intervals across multiple sites that utilize different methods for reporting colonoscopy findings.

Lack of significant association between serum inflammatory cytokine profiles and the presence of colorectal adenoma

Background

Inflammatory cytokines in the colonic microenvironment have been shown to increase with advance colorectal cancer disease state. However, the contribution of inflammatory cytokines to pre-malignant disease, such as the formation of adenomas, is unclear.

Methods

Using the Milliplex® MAP Human Cytokine/ Chemokine Magnetic Bead Panel Immunoassay, serum cytokine and chemokine profiles were assayed among participants without an adenoma (n = 97) and those with an adenoma (n = 97) enrolled in the NCI-funded Insulin Resistance Atherosclerosis Colon Study. The concentrations of interleukin-10 (IL-10), IL-1β, IL-6, IL-17A, IL-2, IL-4, IL-7, IL-12(p70), interferon-γ (IFN-γ), macrophage chemoattractant protein-1 (MCP-1), regulated on activation, normal T cell expressed and secreted (RANTES), tumor necrosis factor-alpha (TNF-α), vascular endothelial growth factor (VEGF), granulocyte macrophage colony-stimulating factor (GM-CSF), and macrophage inflammatory protein-1β (MIP-1β) were determined. Multiple logistic regression analyses were used to evaluate the association between adenoma prevalence and cytokine levels.

Results

The presence of colorectal adenomas was not associated with significant increases in the systemic levels of proinflammatory (TNF-α, IL-6, IL-1β) or T-cell polarizing (IL-12, IL-2, IL-10, IL-4, IL-17, IFN-γ) cytokines. Furthermore, MCP-1 and RANTES levels were equivalent in the serum of study participants with and without adenomas.

Conclusions

These findings suggest colorectal adenoma prevalence may not be associated with significant alterations in systemic inflammation.

Familial colorectal cancer risk by subsite of primary cancer: a population-based study in Utah

BACKGROUND

Familial occurrence is common in colorectal cancer (CRC), but whether this increased familial risk differs by colonic subsite of the index patients CRC is not well understood.

AIM

To quantify the risk of CRC in first-degree (FDR), second-degree (SDR) and first cousin (FC) relatives of individuals with CRC, stratified by subsite in the colorectum and age at diagnosis.

METHODS

Colorectal cancers diagnosed between 1980 and 2010 were identified from the Utah Cancer Registry and linked to pedigrees from the Utah Population Database. Age and gender-matched CRC-free controls were selected to form the comparison group for determining CRC risk in relatives using Cox regression analysis.

RESULTS

Of the 18,208 index patients diagnosed with CRC, 6584 (36.2%) were located in the proximal colon, 5986 (32.9%) in the distal colon and 5638 (31%) in the rectum. The elevated risk of CRC in relatives was similar in analysis stratified for CRC colorectal subsites in the index cases. FDR had similarly elevated risk of all site CRC, whether the index patient had cancer in the proximal colon [hazards ratio (HR): 1.85; 95% CI: 1.70-2.02], distal colon (HR: 1.90; 95% CI: 1.73-2.08) or rectum (HR: 1.83; 95% CI: 1.66-2.02) compared to relatives of controls. This risk was consistently greater for FDR when cases developed CRC below the age of 60 years.

CONCLUSIONS

Relatives of CRC patients have a similarly elevated risk of CRC regardless of colonic tumour subsite in the index patient, and it is greatest for relatives of younger age index cases.

Abstract LB-276: Prospective study of body mass index and adult weight change with colorectal cancer survival, overall and by tumor microsatellite instability status

Background: Tumor features such as stage, grade, and microsatellite instability (MSI) status have relevance for colorectal cancer survival whereas the prognostic role of body mass index (BMI) is unclear. We assessed the association of BMI and adult weight gain on colorectal cancer survival, overall and by strata of sex and MSI.

Methods: Participants were identified from a multi-center cohort that includes 6,763 colorectal cancer patients with invasive colorectal cancer who were enrolled into the Colon Cancer Family Registry from 1997 to 2008. Vital status was updated through direct contact with patients/next-of-kin and/or linkage with mortality records. BMI 2 years before diagnosis, BMI at age 20 years, and adult weight gain were derived from self-reports of height and weight (i.e., weight 2 years before diagnosis and weight at age 20 years). Tumor MSI status was available for 4,987 patients. Multivariable, two-sided hazard ratios (HR) and 95% confidence intervals (CIs) were estimated from delayed-entry Cox proportional hazards models, controlling for age at diagnosis, TNM summary stage (i.e., I, II, III, IV or missing), smoking (current, former, never), and study center.

Results: After a maximum of 13.7 years of follow-up from enrollment to end-of-study (median: 5.3 years), 2,335 patients had died. Higher BMI 2 years before cancer diagnosis (per 5-kg/m2) was associated with higher risk of all-cause mortality overall (HR, 1.10; 95% CI, 1.05 to 1.14), with similar associations when stratified by sex (men: HR, 1.07; 95% CI, 1.02 to 1.14; women: HR, 1.11: 95% CI, 1.05 to 1.17; p-interaction: 0.18) and MSI status (MS-stable/MSI-low: HR, 1.08; 95% CI, 1.03 to 1.14; MSI-high, HR: 1.19; 95% CI, 1.02 to 1.40; p-interaction: 0.88). In joint models, with MS-stable/MSI-low and normal BMI as the referent group, risk of death was lower for those with MSI-high and normal BMI (HR: 0.77; 95% CI: 0.59 to 1.00), higher for MS-stable/MSI-low and high (≥30) BMI (HR: 1.23; 95% CI: 1.07 to 1.42), and essentially the same for MSI-high and high BMI (HR: 0.97; 95% CI: 0.72 to 1.30). Similar patterns of association were observed for BMI at age 20 years and when the outcome was colorectal cancer-specific mortality, although not all associations remained statistically significant for some of the smaller sub-group analyses. After controlling for BMI at age 20 years, adult weight gain was only modestly associated with all-cause mortality (per 5 kg HR: 1.01; 95% CI: 1.00 to 1.02; p-trend: 0.07).

Conclusion: High pre-diagnosis BMI was associated with increased mortality after colorectal cancer diagnosis; this association was consistent for men and women and by tumor MSI status. These results also suggest that obesity attenuates the survival advantage observed with MSI-high tumors.

Citation Format: Peter T. Campbell, Christina Newton, Polly A. Newcomb, Dennis Ahnen, John Baron, Sean Cleary, Michelle Cotterchio, A. Brad Farris, Jane Figueiredo, Roger C. Green, Loic Le Marchand, John McLaughlin, Amanda Phipps, John D. Potter, Andrew Renehan, Aung Ko Win, Noralane Lindor, Paul Limburg. Prospective study of body mass index and adult weight change with colorectal cancer survival, overall and by tumor microsatellite instability status. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-276. doi:10.1158/1538-7445.AM2014-LB-276

Immunohistochemical testing of conventional adenomas for loss of expression of mismatch repair proteins in Lynch syndrome mutation carriers: a case series from the Australasian site of the colon cancer family registry

Debate continues as to the usefulness of assessing adenomas for loss of mismatch repair protein expression to identify individuals with suspected Lynch syndrome. We tested 109 polyps from 69 proven mutation carriers (35 females and 34 males) belonging to 49 Lynch syndrome families. All polyps were tested by immunohistochemistry for four mismatch repair proteins MLH1, MSH2, MSH6 and PMS2. Detailed pathology review was performed by specialist gastrointestinal pathologists. The majority of polyps (86%) were conventional adenomas (n=94), with 65 tubular and 28 tubulovillous adenomas and a single villous adenoma. The remaining 15 lesions (14%) were serrated polyps. Overall, loss of mismatch repair expression was noted for 78/109 (72%) of polyps. Loss of mismatch repair expression was seen in 74 of 94 (79%) conventional adenomas, and 4 of 15 (27%) serrated polyps from mismatch repair gene mutation carriers. In all instances, loss of expression was consistent with the underlying germline mutation. Mismatch repair protein expression was lost in 27 of 29 adenomas with a villous component compared with 47 of 65 adenomas without this feature (93 vs 73%; P=0.028). A strong trend was observed for high-grade dysplasia. Mismatch repair deficiency was observed in 12 of 12 conventional adenomas with high-grade dysplasia compared with 60 of 79 with low-grade dysplasia (100 vs 76%; P=0.065). We were unable to demonstrate a significant association between conventional adenoma size or site and mismatch repair deficiency. All (4/4 or 100%) of the serrated polyps demonstrating mismatch repair deficiency were traditional serrated adenomas from a single family. Diagnostic testing of adenomas in suspected Lynch syndrome families is a useful alternative in cases where cancers are unavailable. The overwhelming majority of conventional adenomas from mutation carriers show loss of mismatch repair protein expression concordant with the underlying germline mutation.

Lack of association between insulin sensitivity and colorectal adenoma risk

Insulin resistance is thought to mediate the association between obesity and colorectal neoplasia, but no prior studies have assessed stimulated insulin sensitivity as a risk factor for colorectal neoplasia. This prospective study examined the association between insulin sensitivity measured directly using the frequently sampled intravenous glucose tolerance test (FSIGT) and later risk of colorectal adenomas. Among participants with a range of glucose tolerance levels enrolled in the Insulin Resistance Atherosclerosis Study, colonoscopies were conducted on 600 participants ages ≥50 yr, regardless of symptoms, about 10 yr after the first FSIGT and 5 yr after the second. Multiple logistic regression analyses were used. Within this cohort, diabetes was not associated with colorectal adenoma risk [∼10 yr prior to colonoscopy adjusted odds ratio (OR(adj)) 1.00; 95% confidence interval (CI), 0.62-1.62 or ∼5 yr prior to colonoscopy OR(adj) 0.96; 95% CI, 0.62-1.50]. Among non-diabetic participants, insulin sensitivity was not associated with colorectal adenoma risk at either prior study visit [lowest vs. highest insulin sensitivity, ∼10 yr prior to colonoscopy OR(adj) 0.93; 95% CI 0.50-1.71 and ∼5 yr prior to colonscopy OR(adj) 0.74; 95% CI, 0.38-1.46]. These results suggest that factors other than insulin sensitivity mediate the relationship between obesity and colorectal neoplasia.

Association between folate levels and CpG Island hypermethylation in normal colorectal mucosa

Gene-specific promoter methylation of several genes occurs in aging normal tissues and may predispose to tumorigenesis. In the present study, we investigate the association of blood folate levels and dietary and lifestyle factors with CpG island (CGI) methylation in normal colorectal mucosa. Subjects were enrolled in a multicenter chemoprevention trial of aspirin or folic acid for the prevention of large bowel adenomas. We collected 1,000 biopsy specimens from 389 patients, 501 samples from the right colon and 499 from the rectum at the follow-up colonoscopy. We measured DNA methylation of estrogen receptor alpha (ERα) and secreted frizzled related protein-1 (SFRP1), using bisulfite pyrosequencing. We used generalized estimating equations regression analysis to examine the association between methylation and selected variables. For both ERα and SFRP1, percentage methylation was significantly higher in the rectum than in the right colon (P = 0.001). For each 10 years of age, we observed a 1.7% increase in methylation level for ERα and a 2.9% increase for SFRP1 (P < 0.0001). African Americans had a significantly lower level of ERα and SFRP1 methylation than Caucasians and Hispanics. Higher RBC folate levels were associated with higher levels of both ERα (P = 0.03) and SFRP1 methylation (P = 0.01). Our results suggest that CGI methylation in normal colorectal mucosa is related to advancing age, race, rectal location, and RBC folate levels. These data have important implications regarding the safety of supplementary folate administration in healthy adults, given the hypothesis that methylation in normal mucosa may predispose to colorectal neoplasia.

The association of lifestyle and dietary factors with the risk for serrated polyps of the colorectum

Some serrated polyps of the colorectum are likely preinvasive lesions, evolving through a newly recognized serrated pathway to colorectal cancer. To assess possible risk and protective factors for serrated polyps and particularly to explore differences in risk factors between polyps in the right and left colorectum, we pooled data from three large multicenter chemoprevention trials. A serrated polyp was defined broadly as any serrated lesion (hyperplastic, sessile serrated adenoma, "traditional" serrated adenoma, mixed adenoma) diagnosed during each trial's main treatment period of approximately 3 to 4 years. Using generalized linear regression, we computed risk ratios and 95% confidence intervals as measures of the association between risk for serrated polyps and demographic, lifestyle, and dietary variables. Of the 2,830 subjects that completed at least one follow-up exam after randomization, 675 (23.9%) had at least one left-sided serrated polyp and 261 (9.2%) had at least one right-sided lesion. In the left colorectum, obesity, cigarette smoking, dietary fat, total energy intake, and red meat intake were associated with an increased risk for serrated polyps. In the right colon, aspirin treatment was associated with a reduced risk and family history of polyps and folate treatment were associated with an increased risk for serrated polyps. Our results suggest that several common lifestyle and dietary variables are associated with risk for serrated polyps, and some of these may differ for the right and left colorectum.

The association of tumor microsatellite instability phenotype with family history of colorectal cancer

Family history is a strong predictor of colorectal cancer risk; however, a diagnosis of colorectal cancer among first-degree relatives has not been systematically investigated as a function of the colorectal cancer molecular subtypes related to tumor microsatellite instability (MSI) status. We investigated whether the observable familial colorectal cancer risks differed according to tumor MSI subtypes, stratified as MSI-High (>30% instability), MSI-Low (<30% instability), and MSS (no instability). Data from 3,143 population-based colorectal cancer cases from five institutions were assessed for family history according to the Amsterdam criteria and the Bethesda guidelines, age at diagnosis, sex, tumor location, and MSI status. The distribution of patient characteristics by MSI status was compared using polytomous logistic regression. Overall, 2.8% colorectal cancer cases met the Amsterdam criteria and 37% met the Bethesda guidelines. There were 14% MSI-High, 13% MSI-Low, and 73% MSS colorectal cancers. MSI-High (P<0.0001) and MSI-Low tumors (P=0.01) were more proximally located than MSS tumors. MSI-High tumors were more common among females (P<0.001). The highest proportion of MSI-High tumors occurred in cases<40 years of age whereas the age-dependent distribution of MSI-Low tumors was unchanged. MSI-High tumors showed a statistically significant association with increasing numbers of first-degree relatives with colorectal cancer (P=0.002); this association disappeared, however, when MSI-High cases meeting Amsterdam criteria were removed from the analysis. MSI-Low tumors did not show a similar association with family history of colorectal cancer. Familial risk associated with MSI-High tumors is primarily driven by the Amsterdam-criteria patients. MSI-Low tumors may represent a distinct subtype of colorectal cancer with respect to certain epidemiologic variables studied here.

High detection rates of colorectal neoplasia by stool DNA testing with a novel digital melt curve assay

BACKGROUND & AIMS

Current stool DNA tests identify about half of individuals with colorectal cancers and miss most individuals with advanced adenomas. We developed a digital melt curve (DMC) assay to quantify low-abundance mutations in stool samples for detection of colorectal neoplasms and compared this test with other approaches.

METHODS

We combined a melt curve assay with digital polymerase chain reaction and validated the quantitative range. We then evaluated its ability to detect neoplasms in 2 clinical studies. In study I, stool samples from patients with colorectal tumors with known mutations (KRAS, APC, BRAF, TP53) were assayed. In study II, archived stool samples from patients with advanced adenomas containing known KRAS mutations were assayed, along with controls. Results were compared with those from the stool DNA test PreGenPlus (Exact Sciences, Marlborough, MA), Hemoccult, and HemoccultSensa (both Beckman-Coulter, Fullerton, CA).

RESULTS

The DMC assay detected samples in which only 0.1% of target genes were mutated. In study I, the DMC assay detected known mutations in 28 (90%) of 31 tumor samples and 6 (75%) of 8 advanced adenoma samples. In study II, the DMC assay detected 16 (59%) of 27 advanced adenoma samples that contained KRAS mutations, compared with 7% with the Hemoccult, 15% with the HemoccultSensa, and 26% with the PreGenPlus assays (P < .05 for each, compared with the DMC assay); specificities did not differ significantly.

CONCLUSIONS

The DMC assay has a high level of sensitivity in detecting individuals with colon neoplasms and is better than current stool screening methods in detecting those with advanced adenomas. Further studies are indicated.

MTHFR genotype and colorectal adenoma recurrence: data from a double-blind placebo-controlled clinical trial

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in folate metabolism. We assessed the association between two common MTHFR variants, 677C>T and 1298A>C, and adenoma recurrence in the context of a randomized double- blind clinical trial of aspirin use and folate supplementation. We used generalized linear regression to estimate risk ratios and 95% confidence intervals (95% CI) for recurrence, adjusting for age, sex, clinical center, follow-up time, and treatment status. Neither MTHFR polymorphism was associated with overall or advanced adenoma recurrence. Compared with those with two wild-type alleles, the relative risk for advanced adenoma was 0.75 (95% CI, 0.36-1.55) for the MTHFR 677 TT genotype and 1.16 (95% CI, 0.58-2.33) for the MTHFR 1298 CC genotype. The effect of folate supplementation on recurrence risk did not differ by genotype. Our findings indicate that the MTHFR genotype does not change adenoma risk in a manner similar to its effect on colorectal cancer, and does not modify the effect of folate supplementation on metachronous adenoma risk.

Priorities in colorectal cancer research: recommendations from the Gastrointestinal Scientific Leadership Council of the Coalition of Cancer Cooperative Groups

Emerging technologies have greatly expanded our ability to detect, characterize, and treat colorectal cancer. The Coalition of Cancer Cooperative Groups convened a multidisciplinary panel, the Scientific Leadership Council in GI cancer, to discuss and advise on the priorities and opportunities to advance current and future approaches into the clinical arena to impact most rapidly the morbidity and mortality from this disease. The Council's recommendations for research priorities are the result of engagement of community and academic oncologists, patient advocacy groups, and other stakeholders including the pharmaceutical industry and governmental agencies. We detail some key prospects for investigation in the areas of colon cancer detection, prevention, and surgical and medical management. Many are in early or definitive clinical trials, and a focus on rapid accrual is urged. The implementation of biology-directed laboratory investigations, both in association with ongoing clinical trials and as a separate developmental strategy for targeted therapies, is supported as the route to individualized therapy.

What do cancer survivors believe causes cancer? (United States)

OBJECTIVE

To describe cancer survivors' beliefs about the causes of prostate, colorectal or breast cancers.

METHODS

A survey of beliefs about cancer causation was completed by 670 cancer survivors (416 with breast cancer, 165 with prostate cancer and 89 with colorectal cancer) enrolled in a population-based study in Colorado. Categorical analysis was used to describe associations between participant's beliefs about the cause of their cancer type, both in themselves and in others, and personal characteristics, including gender, age, and familial cancer risk.

RESULTS

Cancer survivors most frequently reported genetic factors, smoking, environmental factors (e.g., pollutants or occupation), and psychosocial factors (e.g., stress) as causing their type of cancer. Respondents underestimated the importance of behavioral factors that are known to be associated with increased cancer risk, such as obesity and physical inactivity, while overestimating the importance of stress and environmental pollution.

CONCLUSIONS

Cancer survivors' beliefs about what causes cancer are substantially different than those of experts. Because those affected by cancer should be well informed about the causes of cancer, educational efforts are needed, especially regarding the importance of factors that can be modified to reduce cancer risk.

Colorectal cancer in patients under close colonoscopic surveillance

BACKGROUND & AIMS

Colonoscopic polypectomy is considered effective for preventing colorectal cancer (CRC), but the incidence of cancer in patients under colonoscopic surveillance has rarely been investigated. We determined the incidence of CRC in patients under colonoscopic surveillance and examined the circumstances and risk factors for CRC and adenoma with high-grade dysplasia.

METHODS

Patients were drawn from 3 adenoma chemoprevention trials. All underwent baseline colonoscopy with removal of at least one adenoma and were deemed free of remaining lesions. We identified patients subsequently diagnosed with invasive cancer or adenoma with high-grade dysplasia. The timing, location, and outcome of all cases of cancer and high-grade dysplasia identified are described and risks associated with their development explored.

RESULTS

CRC was diagnosed in 19 of the 2915 patients over a mean follow-up of 3.7 years (incidence, 1.74 cancers/1000 person-years). The cancers were located in all regions of the colon; 10 were at or proximal to the hepatic flexure. Although most of the cancers (84%) were of early stage, 2 participants died of CRC. Seven patients were diagnosed with adenoma with high-grade dysplasia during follow-up. Older patients and those with a history of more adenomas were at higher risk of being diagnosed with invasive cancer or adenoma with high-grade dysplasia.

CONCLUSIONS

CRC is diagnosed in a clinically important proportion of patients following complete colonoscopy and polypectomy. More precise and representative estimates of CRC incidence and death among patients undergoing surveillance examinations are needed.

A randomized trial of aspirin to prevent colorectal adenomas

BACKGROUND

Laboratory and epidemiologic data suggest that aspirin has an antineoplastic effect in the large bowel.

METHODS

We performed a randomized, double-blind trial of aspirin as a chemopreventive agent against colorectal adenomas. We randomly assigned 1121 patients with a recent history of histologically documented adenomas to receive placebo (372 patients), 81 mg of aspirin (377 patients), or 325 mg of aspirin (372 patients) daily. According to the protocol, follow-up colonoscopy was to be performed approximately three years after the qualifying endoscopy. We compared the groups with respect to the risk of one or more neoplasms (adenomas or colorectal cancer) at least one year after randomization using generalized linear models to compute risk ratios and 95 percent confidence intervals.

RESULTS

Reported adherence to study medications and avoidance of nonsteroidal antiinflammatory drugs were excellent. Follow-up colonoscopy was performed at least one year after randomization in 1084 patients (97 percent). The incidence of one or more adenomas was 47 percent in the placebo group, 38 percent in the group given 81 mg of aspirin per day, and 45 percent in the group given 325 mg of aspirin per day (global P=0.04). Unadjusted relative risks of any adenoma (as compared with the placebo group) were 0.81 in the 81-mg group (95 percent confidence interval, 0.69 to 0.96) and 0.96 in the 325-mg group (95 percent confidence interval, 0.81 to 1.13). For advanced neoplasms (adenomas measuring at least 1 cm in diameter or with tubulovillous or villous features, severe dysplasia, or invasive cancer), the respective relative risks were 0.59 (95 percent confidence interval, 0.38 to 0.92) and 0.83 (95 percent confidence interval, 0.55 to 1.23).

CONCLUSIONS

Low-dose aspirin has a moderate chemopreventive effect on adenomas in the large bowel.

Basic concepts for genetic testing in common hereditary colorectal cancer syndromes

Approximately 5% of colorectal cancers are associated with one of the autosomal dominant hereditary cancer syndromes. The two most common familial colon cancer syndromes are familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC). The causative mutation can be identified in many families with these syndromes by genetic testing of an affected individual. If an affected individual tests positive for a disease-causing mutation, genetic testing of unaffected, at-risk family members can be performed to determine whether they have inherited the cancer-susceptibility mutation, and a personalized cancer surveillance strategy can be devised. Genetic testing significantly enhances cancer risk assessment in these families. However, the complicated nature of result interpretation and the emotional impact of the result necessitate that testing be carried out in conjunction with patient education and informed consent by a physician who has a keen appreciation for the inherent challenges. This article describes the genetic testing strategy in HNPCC and FAP.

Primary prevention of colorectal cancer: diet and drugs

Primary prevention of colonic adenomas and cancer through dietary interventions or chemoprevention has great appeal. This article discusses primary prevention goals and promising nutritional or chemopreventive strategies. There is substantial observational evidence that diets high in total calories and fat and or low in fruits and vegetables or total fiber as well as low levels of physical activity are related to the risk of colonic neoplasia. Similar observational data indicate that diets high in specific nutrients such as antioxidant vitamins or calcium may be protective. The article describes some of the newer chemopreventive agents and reviews the data linking diet and lifestyle to colorectal cancer risk, focusing on interventions that have also been studied in prospective clinical trials. Finally the evidence supporting the role of non-steroidal anti-inflammatory drugs for the chemoprevention of CRC is reviewed and the status of several other promising newer agents that are entering human trials is summarized.

Process of care and outcomes for elderly patients hospitalized with peptic ulcer disease: results from a quality improvement project

CONTEXT

Since publication in 1994 of guidelines for management of peptic ulcer disease (PUD), trends in physician practice and outcomes related to guideline application have not been evaluated.

OBJECTIVES

To describe changes in process of care that occurred in a quality improvement program for patients hospitalized with PUD and to evaluate associations between in-hospital treatment of PUD and 1-year rehospitalization for PUD and mortality in a subset of these patients.

DESIGN, SETTING, AND PATIENTS

Cohort study of 4292 sequential Medicare beneficiaries hospitalized at acute care hospitals with a principal diagnosis of PUD in 5 states (Colorado, Georgia, Connecticut, Oklahoma, and Virginia) in 1995 (baseline) and 1997 (remeasurement); outcomes were evaluated for 752 patients in Colorado.

MAIN OUTCOME MEASURES

Changes in rates of screening for Helicobacter pylori infection, treatment for H pylori infection, screening for nonsteroidal anti-inflammatory drug (NSAID) use, counseling about NSAID use; outcomes included rehospitalization for PUD and all-cause mortality within 1 year of discharge in Colorado.

RESULTS

Screening for H pylori infection increased significantly (12%-19% increase; P<.001) in each of the 5 states. Treatment of H pylori infection increased in each state and was significantly increased for the entire group of hospitalizations examined (8% increase overall; P =.001). Despite increased screening, detection of H pylori infection was less frequent than expected in every state, (13%-24%) and did not increase in any state. Screening for and counseling about NSAIDs did not significantly increase overall or in any state. In the Colorado cohort, the proportion of patients rehospitalized was unchanged in 1995 (8.9%) and 1997 (6.8%), and 124 patients (16%) in the combined 1995 and 1997 cohorts died within 1 year. Treatment for H pylori was not associated with a reduction in rehospitalization within 1 year (adjusted odds ratio [OR], 1.24; 95% confidence interval [CI], 0.65-2.36) or with a reduction in mortality (adjusted OR, 1.08; 95% CI, 0.68-1.71). Counseling about NSAID use was associated with a decrease in risk of 1-year rehospitalization for PUD (adjusted OR, 0.47; 95% CI, 0.22-0.99) and risk of all-cause mortality (adjusted OR, 0.44; 95% CI, 0.26-0.75).

CONCLUSIONS

This quality improvement program for elderly patients with PUD resulted in increased screening for H pylori and increased treatment of H pylori infection but no change in counseling about NSAID use. However, with the low prevalence of H pylori detected, treatment of H pylori infection was not associated with a reduction in repeat hospitalization for PUD or subsequent mortality, whereas counseling about the risks of using NSAIDs was associated with a reduction in the risk of both outcomes.

Long-term outcome of medical and surgical therapies for gastroesophageal reflux disease: follow-up of a randomized controlled trial

CONTEXT

Severe gastroesophageal reflux disease (GERD) is a lifelong problem that can be complicated by peptic esophageal stricture and adenocarcinoma of the esophagus.

OBJECTIVE

To determine the long-term outcome of medical and surgical therapies for GERD.

DESIGN AND SETTING

Follow-up study conducted from October 1997 through October 1999 of a prospective randomized trial of medical and surgical antireflux treatments in patients with complicated GERD. Mean (median) duration of follow-up was 10.6 years (7.3 years) for medical patients and 9.1 years (6.3 years) for surgical patients.

PARTICIPANTS

Two hundred thirty-nine (97%) of the original 247 study patients were found (79 were confirmed dead). Among the 160 survivors (157 men and 3 women; mean [SD] age, 67 [12] years), 129 (91 in the medical treatment group and 38 in the surgical treatment group) participated in the follow-up.

MAIN OUTCOME MEASURES

Use of antireflux medication, Gastroesophageal Reflux Disease Activity Index (GRACI) scores, grade of esophagitis, frequency of treatment of esophageal stricture, frequency of subsequent antireflux operations, 36-item Short Form health survey (SF-36) scores, satisfaction with antireflux therapy, survival, and incidence of esophageal adenocarcinoma, compared between the medical antireflux therapy group and the fundoplication surgery group. Information on cause of death was obtained from autopsy results, hospital records, and death certificates.

RESULTS

Eighty-three (92%) of 90 medical patients and 23 (62%) of 37 surgical patients reported that they used antireflux medications regularly (P<.001). During a 1-week period after discontinuation of medication, mean (SD) GRACI symptom scores were significantly lower in the surgical treatment group (82.6 [17.5] vs 96.7 [21.4] in the medical treatment group; P =.003). However, no significant differences between the groups were found in grade of esophagitis, frequency of treatment of esophageal stricture and subsequent antireflux operations, SF-36 standardized physical and mental component scale scores, and overall satisfaction with antireflux therapy. Survival during a period of 140 months was decreased significantly in the surgical vs the medical treatment group (relative risk of death in the medical group, 1.57; 95% confidence interval, 1.01-2.46; P =.047), largely because of excess deaths from heart disease. Patients with Barrett esophagus at baseline developed esophageal adenocarcinomas at an annual rate of 0.4%, whereas these cancers developed in patients without Barrett esophagus at an annual rate of only 0.07%. There was no significant difference between groups in incidence of esophageal cancer.

CONCLUSION

This study suggests that antireflux surgery should not be advised with the expectation that patients with GERD will no longer need to take antisecretory medications or that the procedure will prevent esophageal cancer among those with GERD and Barrett esophagus.

Exisulind induction of apoptosis involves guanosine 3',5'-cyclic monophosphate phosphodiesterase inhibition, protein kinase G activation, and attenuated beta-catenin

Sulindac sulfone (exisulind), although a nonsteroidal anti-inflammatory drug derivative, induces apoptosis in tumor cells by a mechanism that does not involve cyclooxygenase inhibition. SW480 colon tumor cells contain guanosine 3',5'-monophosphate (cGMP) phosphodiesterase (PDE) isoforms of the PDE5 and PDE2 gene families that are inhibited by exisulind and new synthetic analogues. The analogues maintain rank order of potency for PDE inhibition, apoptosis induction, and growth inhibition. A novel mechanism for exisulind to induce apoptosis is studied involving sustained increases in cGMP levels and cGMP-dependent protein kinase (PKG) induction not found with selective PDE5 or most other PDE inhibitors. Accumulated beta-catenin, shown to be a substrate for PKG, is decreased by exisulind, suggesting a mechanism to explain apoptosis induction in neoplastic cells harboring adenomatous polyposis coli gene mutations.

Review article: potential gastrointestinal effects of long-term acid suppression with proton pump inhibitors

This review examines the evidence for the development of adverse effects due to prolonged gastric acid suppression with proton pump inhibitors. Potential areas of concern regarding long-term proton pump inhibitor use have included: carcinoid formation; development of gastric adenocarcinoma (especially in patients with Helicobacter pylori infection); bacterial overgrowth; enteric infections; and malabsorption of fat, minerals, and vitamins. Prolonged proton pump inhibitor use may lead to enterochromaffin-like cell hyperplasia, but has not been demonstrated to increase the risk of carcinoid formation. Long-term proton pump inhibitor treatment has not been documented to hasten the development or the progression of atrophic gastritis to intestinal metaplasia and gastric cancer, although long-term studies are required to allow definitive conclusions. At present, we do not recommend that patients be tested routinely for H. pylori infection when using proton pump inhibitors for prolonged periods. Gastric bacterial overgrowth does increase with acid suppression, but important clinical sequelae, such a higher rate of gastric adenocarcinoma, have not been seen. The risk of enteric infection may increase with acid suppression, although this does not seem to be a common clinical problem with prolonged proton pump inhibitor use. The absorption of fats and minerals does not appear to be significantly impaired with chronic acid suppression. However, vitamin B12 concentration may be decreased when gastric acid is markedly suppressed for prolonged periods (e.g. Zolllinger-Ellison syndrome), and vitamin B12 levels should probably be assessed in patients taking high-dose proton pump inhibitors for many years. Thus, current evidence suggests that prolonged gastric acid suppression with proton pump inhibitors rarely, if ever, produces adverse events. Nevertheless, continued follow-up of patients taking proton pump inhibitors for extended periods will provide greater experience regarding the potential gastrointestinal adverse effects of long-term acid suppression.

Validity of self-reported colorectal cancer screening behavior

End points for trials promoting cancer screening are often based on self-reported screening behavior. This study was designed to evaluate and optimize the reliability of a computer-assisted telephone interview for collecting self-reported colorectal cancer screening behavior. Cases who had received a fecal occult blood test (FOBT), flexible sigmoidoscopy, and/or colonoscopy, and controls who had no record of colorectal screening were identified among 40-75-year-old members of the Denver Kaiser Permanente Health Care Program and were contacted by telephone. Sensitivities and specificities of self-reported screening were calculated by comparison of subjects' recall with Kaiser Permanente records. The questionnaire was revised based upon results of the pilot phase of the study. Using the revised questionnaire, the sensitivity of self-reported screening was 96.2% for the FOBT, 94.9% for flexible sigmoidoscopy, 88.7% for colonoscopy, and 96.2% for either endoscopic screening test. The specificity of self-reported screening was 85.9% for the FOBT, 92.2% for flexible sigmoidoscopy, 96.8% for colonoscopy, and 92.0% for either endoscopic screening test. No marked differences in the accuracy of the self-reports were detected as a function of gender, age, ethnicity, or family history of colorectal cancer of the participants. Self-reports of colon cancer screening behavior can be reliably used as end points for intervention trials when carefully phrased questions are used.

Promoting cancer screening among the first-degree relatives of breast and colorectal cancer patients: the design of two randomized trials

BACKGROUND

In this paper two large nationwide trials are described, both of which will test a comparable telephone-based counseling intervention to promote cancer screening among the first-degree relatives (FDRs) of breast and colorectal cancer patients. The unit of randomization will be the family unit of eligible FDRs. Access to FDRs will be obtained from their relatives with cancer. Selected intervention and design issues are reviewed, including how both projects will respond to FDRs who exhibit significant levels of cancer-specific anxiety or distress and how potential high-risk cancer families will be accommodated.

METHODS

Pursuant to the development of both studies, two feasibility surveys were conducted to determine whether patients would grant access to their FDRs and whether the FDRS identified by these patients would be receptive to the telephone intervention.

RESULTS

Approximately 80% (106 of 132) of breast cancer patients agreed to provide access to their eligible FDRs when contacted on-site at participating hospitals and clinics. Of those subsequently selected for telephone follow-up (n = 95 or 90%), 80% (n = 76) were successfully contacted by telephone, and of these 97% (n = 74) provided the names and telephone numbers of their FDRs. Among colorectal cancer patients contacted on-site (n = 46), 96% (n = 44) agreed to provide access to their FDRs, and of those contacted by telephone (n = 33 or 75%), 91% (n = 30) provided the requested information about their FDRs. Once contacted, 95% of breast cancer FDRs (55 of 58) and 91% of colorectal cancer patients (51 of 56) endorsed the intervention strategy.

CONCLUSIONS

It is argued that this intervention, if proven effective, could provide an exportable strategy for reaching large numbers of high-risk individuals to promote cancer screening.

Effects of milk and milk products on rectal mucosal cell proliferation in humans

Intake of dairy products and major dairy constituents (e.g., calcium) has been proposed to reduce the risk of colorectal cancer, although epidemiological studies have yielded inconclusive results. We conducted a randomized cross-over trial to test the effects of high- and low-dairy consumption diets on rectal mucosal proliferation, a possible intermediary marker for large bowel cancer. From a gastroenterology clinic at an academic medical center, we recruited 40 patients, ages 25-79 years, who had either a history of a large bowel adenoma or a first-degree relative with large bowel cancer. Participants completed a baseline questionnaire covering demographic characteristics, health history, and habits and a food frequency questionnaire. They were randomized to a 12-week diet of either high dairy intake (six dairy servings/day) or low dairy intake (<0.5 serving of dairy products/day), with an intervening 12-week washout period in which they were asked to resume their usual diet before crossing over to the alternate study diet for the last 12-week period of the study. Adherence to the study diets was monitored by a daily dairy intake checklist and periodic, unscheduled 24-h dietary recalls. Biopsies of the rectal mucosa were obtained at the beginning and end of each intervention phase. Two assays of rectal mucosal cell proliferation were performed: immunohistochemical determination of proliferating cell nuclear antigen and whole crypt mitotic count. We found no statistically significant changes in either of these proliferation measures as a result of high or low dairy intake. There was no correlation between the labeling index for proliferating cell nuclear antigen and whole crypt mitotic count; however, measures of the location and intensity of cell proliferation within the rectal crypt were highly correlated between the two assays. Thus, our study indicates that greater consumption of dairy products over a 12-week period does not change rectal mucosal cell proliferation.

AOM-induced mouse colon tumors do not express full-length APC protein

While evidence in both sporadic and inherited human colorectal cancer and MIN mice implicate the tumor suppressor gene, APC, in the causation of colorectal carcinogenesis, this gene has not been confirmed to be involved in rodent chemically-induced colon cancer models (RCCM). These experimental models are widely used to elucidate mechanisms involved in colon carcinogenesis (initiation, promotion and progression) as well as studies on chemoprevention (dietary and other) and intervention. To validate the RCCM as relevant models for sporadic human colorectal cancer, and to facilitate research on the role of the APC gene in colon carcinogenesis, we investigated the role of APC in azoxymethane (AOM)-induced colorectal tumors in mice. Using an antibody that recognizes the carboxy terminus of APC, we have characterized the pattern of staining observed in normal mouse intestinal tissue, in MIN mouse intestinal adenomas and in AOM-induced mouse colon tumors. The APC protein was localized in the cytoplasm of normal colonic epithelial cells. In the small intestine there was APC immunoreactivity along the villous and staining of the Paneth cells at the base of the glands. In the proximal and distal colonic crypts there appeared to be a gradient of staining which increased towards the luminal surface. This gradient was not as apparent in the small intestinal villi. Nuclei and mucus in the goblet cells showed no immunoreactivity. MIN mouse small bowel and colonic adenomas, known to have lost APC, stained negatively for APC. AOM-induced adenomas and carcinomas also consistently stained negatively using this antibody. This study demonstrates for the first time the loss of wild-type APC protein in AOM-induced mouse colon tumors and suggests that alterations in expression of this tumor suppressor gene, which is so commonly mutated in human colon cancer, is also involved in this animal model of colon cancer.

Sialosyl-Tn antigen: initial report of a new marker of malignant progression in long-standing ulcerative colitis

BACKGROUND & AIMS

Expression of the mucin-associated carbohydrate antigen sialosyl-Tn (STn) correlates with malignant transformation in sporadic colonic neoplasms. The aim of this study was to analyze STn antigen expression in patients with long-standing ulcerative colitis (UC).

METHODS

STn antigen was assessed by immunohistochemistry in archival tissues. Study A was a retrospective chronological case-control study. Serial surveillance colonoscopic biopsy specimens without inflammation or dysplasia were analyzed in 7 patients who developed colon cancer and in 8 controls who did not develop colon cancer. Study B analyzed the anatomic distribution of STn expression in 17 cancer-bearing (case) and 6 cancer-free (control) colectomy specimens from patients with UC. In some colectomy specimens, STn was compared with aneuploidy, which was determined by flow cytometry.

RESULTS

In study A, among the 7 patients with UC who developed cancer, 6 patients (86%) expressed STn in at least one prior nondysplastic surveillance biopsy specimen from the same site. Only 3 of 8 control patients (38%) expressed STn. In study B, STn was expressed in 40 of 82 specimens (49%) from cancer-bearing colons but only 8 of 62 specimens (13%) from cancer-free colons. STn was expressed in most aneuploid areas but was also found in diploid, nondysplastic mucosa.

CONCLUSIONS

STn antigen seems to be a promising marker of cancer risk in patients with UC.

Do NSAIDs exert their colon cancer chemoprevention activities through the inhibition of mucosal prostaglandin synthetase?

Nonsteroidal antiinflammatory drugs (NSAIDs) have considerable potential as chemopreventive agents for colorectal cancer. Recent case-control drug surveillance and large cohort studies found that patients with regular aspirin use had a reduced incidence of colorectal cancer and/or decreased death rate from this disease. Several different NSAIDs reduce formation of both colon adenomatous polyps (the precursor lesion of colon cancer) and cancers in experimental animals given known carcinogens. Perhaps most convincing are reports that the NSAID sulindac promotes regression and inhibits recurrence of adenomatous colon polyps in patients with adenomatous polyposis coli. The best characterized pharmacologic effect of the NSAIDs is their reduction of prostaglandin synthesis by inhibiting prostaglandin synthetase PGE2, which catalyzes the formation of prostaglandin precursors from arachidonic acid. Several lines of evidence are contrary to the concept that inhibition of prostaglandin synthesis is central to the NSAIDs' chemopreventive effects. Relatively high levels of prostaglandins have been reported to inhibit tumor cell growth both in vivo and in vitro, and to inhibit differentiation in some tumor cell lines. We evaluated comparative chemopreventive effects on colon tumor formation in an azoxymethane (AOM)-induced colon carcinogenesis rat model using the NSAIDs piroxicam, sulindac, and sulindac sulfone, a metabolite of sulindac which lacks the anti-prostaglandin synthetase activity typically associated with NSAID-induced gastrointestinal toxicities. The results demonstrate that sulindac sulfone, a compound lacking anti-prostaglandin synthetase activity, inhibits AOM-induced colon cancer in rats. Substantial dose-dependent reductions in both tumor burden and tumor multiplicity were observed in the sulindac sulfone-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of transforming growth factor-alpha, epidermal growth-factor receptor and proliferating cell nuclear antigen in gastric-carcinoma - an immunohistochemical study

Forty four cases of human gastric carcinoma were classified as either diffuse or intestinal in type. Serial sections of the paraffin-embedded tumours were stained with either monoclonal antibodies raised against transforming growth factor (TGF-alpha) or proliferating cell nuclear antigen (PCNA) or an affinity purified polyclonal antibody raised against the intracellular domain of the epidermal growth factor receptor (EGFR). Significantly higher levels of staining were found in the intestinal-type carcinomas with all three antibodies. When the extent of staining was arbitrarily divided into low (up to one third of cells stained), medium (one third to two thirds) or a high number of cells stained (two thirds to all of the cells), a much higher proportion (44%) of intestinal type tumours coexpressed TGF-alpha and EGFR to a medium or high level compared to the diffuse group (23%). In the intestinal-type tumours, though not in the diffuse-type tumours, this subgroup of tumours was associated with higher levels of PCNA staining. The relative lack of TGF-alpha or its receptor may be a significant factor in the histogenesis of diffuse gastric carcinoma, and in intestinal-type tumours the coexpression of TGF-alpha and EGFR may be part of an autocrine loop which stimulates the cells to divide.

Trefoil peptide gene expression in gastrointestinal epithelial cells in inflammatory bowel disease

BACKGROUND

This work expands on recent observations that the trefoil peptides pS2 and human spasmolytic polypeptide (hSP) are expressed in the ulceration-associated cell lineage (UACL) glands developing in chronic ulcerative conditions.

METHODS

Trefoil peptide expression in small intestinal Crohn's disease was examined by in situ hybridization to reveal sites of expression of the messenger RNAs encoding pS2 and hSP and by immunohistochemistry and immunoelectron microscopy to localize the peptides in the UACL and adjacent goblet and neuroendocrine cells.

RESULTS

Goblet cells near the UACL expressed pS2 messenger RNA and peptide; ultrastructural immunolocalization revealed pS2 copackaged within mucous cell granules. Neuroendocrine cell hyperplasia was marked in crypts near the UACL; pS2 was copackaged with the neuroendocrine granules.

CONCLUSIONS

Copackaging of a secretory protein, pS2, in both mucous and neuroendocrine granules, which have different functions, is unusual and indicates an important role for pS2 in the secretory process itself or as a ligand delivered to its receptors via different routes. It is concluded that trefoil peptides are of considerable potential functional importance in inflammatory bowel disease.

Trefoil peptide gene expression in gastrointestinal epithelial cells in inflammatory bowel disease

Trefoil peptides are a growing group of proteins with interesting structural and functional properties. We have defined the pattern of trefoil peptide gene expression in the ulceration-associated cell lineage (UACL) and in the nearby mucosa in Crohn's disease. In the UACL, human spasmolytic polypeptide (hSP) mRNA is expressed in the acinar and proximal duct cells, while pS2 mRNA and peptide are found in the distal duct cells and in the surface cells. In adjacent mucosa, pS2 mRNA and protein are expressed by goblet cells, with the pS2 peptide concentrated in the area of the Golgi and also in the theca. Ultrastructural immunolocalisation showed the pS2 to be co-packaged in the mucous cell granules before being secreted into the intestinal lumen. In addition, pS2 peptide was demonstrated in local neuroendocrine cells and was also co-packaged with the neuroendocrine granules. The crypts associated with the UACL also showed marked neuroendocrine cell hyperplasia. We conclude that pS2 peptide is secreted locally into the viscoelastic coat covering the intestinal mucosa which surrounds Crohn's disease ulcers. In addition, it is clear that intestinal goblet cells, in addition to producing mucins, are a rich source of regulatory peptides. Moreover, pS2 is clearly co-packaged with neurosecretory granules, which are released through basal and lateral membranes so that the contained peptides can act in a paracrine manner. These findings are interpreted in terms of the epidermal growth factor/urogastrone released by the UACL, stimulating pS2 gene expression in surrounding cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Benign recurrent intrahepatic cholestasis: treatment with S-adenosylmethionine

S-Adenosylmethionine (800 mg i.v. per day) was used to treat two brothers and a brother and sister from each of two kindreds with benign recurrent intrahepatic cholestasis. Symptoms, routine tests of liver function, concentrations of total bile acids, and the oral clearances of [11,12-2H]chenodeoxycholic acid and [24-13C]cholic acid were determined before and after treatment with S-adenosylmethionine. S-Adenosylmethionine did not ameliorate symptoms or biochemical parameters of cholestasis but reduced bile acid clearances in 3 of 4 subjects. Transaminase levels in both subjects of one kindred rose during treatment. These limited, preliminary observations suggest that S-adenosylmethionine may be ineffective in the therapy of benign recurrent intrahepatic cholestasis and may be hepatotoxic in some patients.