Effect of chromoendoscopy in the proximal colon on colorectal neoplasia detection in Lynch syndrome: a multicenter randomized controlled trial.

BACKGROUND AND AIMS: Patients with Lynch syndrome (LS) undergo regular surveillance by colonoscopy because of an increased risk of colorectal neoplasia, particularly in the proximal colon. Chromoendoscopy (CE) has been reported to improve neoplasia detection compared with conventional white-light endoscopy (WLE), but evidence is limited. Our aim was to investigate the effect of CE in the proximal colon on detection of neoplastic lesions during surveillance in LS. METHODS: This was a multicenter prospective randomized controlled trial of 246 patients with LS who were randomly assigned (1:1) to conventional WLE (n = 123) or colonoscopy with CE in the proximal colon (n = 123), stratified for previous colorectal adenomas and enrolling center. Two years after baseline colonoscopy, patients underwent colonoscopy with CE in the proximal colon. The primary outcome was the proportion of patients with at least one neoplastic lesion at baseline and after 2 years. RESULTS: Neoplasia detection rates at baseline colonoscopy were 27% for WLE versus 30% for CE (odds ratio [OR], 1.23; 95% confidence interval [CI], 0.69-2.2; P = .56). In the proximal colon, neoplasia detection rates were 16% for WLE versus 24% for CE (OR, 1.6; 95% CI, 0.9-3.1; P = .13). Total procedure time was 9 minutes longer in the CE group. At follow-up after 2 years, neoplasia detection rates were similar in both groups: 26% for the original WLE group versus 28% for the CE group (OR, 1.1; P = .81). CONCLUSIONS: CE in the proximal colon for LS surveillance was not superior to WLE with respect to the initial detection of neoplasia, and not associated with reduced neoplasia detection rates after 2 years. The value of CE remains to be established. (Clinical trial registration number: NCT00905710.).

Prevalence of small-bowel neoplasia in Lynch syndrome assessed by video capsule endoscopy.

OBJECTIVE: The aim was to determine the prevalence of small-bowel neoplasia in asymptomatic patients with Lynch syndrome (LS) by video capsule endoscopy (VCE). DESIGN: After obtaining informed consent, asymptomatic proven gene mutation carriers aged 35-70 years were included in this prospective multicentre study in the Netherlands. Patients with previous small-bowel surgery were excluded. After bowel preparation, VCE was performed. The videos were read by two independent investigators. If significant lesions were detected, an endoscopic procedure was subsequently performed to obtain histology and, if possible, remove the lesion. RESULTS: In total, 200 patients (mean age 50 years (range 35-69), M/F 88/112), with proven mutations were included. These concerned MLH1 (n = 50), MSH2 (n = 68), MSH6 (n = 76), PMS2 (n = 3) and Epcam (n = 3) mutation carriers. In 95% of the procedures, caecal visualisation was achieved. Small-bowel neoplasia was detected in two patients: one adenocarcinoma (TisN0Mx) and one adenoma, both located in the duodenum. In another patient, a duodenal cancer (T2N0Mx) was diagnosed 7 months after a negative VCE. This was considered a lesion missed by VCE. All three neoplastic lesions were within reach of a conventional gastroduodenoscope. All patients with neoplasia were men, over 50 years of age and without a family history of small-bowel cancer. CONCLUSIONS: The prevalence of small-bowel neoplasia in asymptomatic patients with LS was 1.5%. All neoplastic lesions were located in the duodenum and within reach of conventional gastroduodenoscopy. Although VCE has the potential to detect these neoplastic lesions, small-bowel neoplasia may be missed. TRIAL REGISTRATION NUMBER: NCT00898768.

Adherence to surveillance guidelines after removal of colorectal adenomas: a large, community-based study.

OBJECTIVE: To determine adherence to recommended surveillance intervals in clinical practice. DESIGN: 2997 successive patients with a first adenoma diagnosis (57% male, mean age 59 years) from 10 hospitals, who underwent colonoscopy between 1998 and 2002, were identified via Pathologisch Anatomisch Landelijk Geautomatiseerd Archief: Dutch Pathology Registry. Their medical records were reviewed until 1 December 2008. Time to and findings at first surveillance colonoscopy were assessed. A surveillance colonoscopy occurring within ± 3 months of a 1-year recommended interval and ± 6 months of a recommended interval of 2 years or longer was considered appropriate. The analysis was stratified by period per change in guideline (before 2002: 2-3 years for patients with 1 adenoma, annually otherwise; in 2002: 6 years for 1-2 adenomas, 3 years otherwise). We also assessed differences in adenoma and colorectal cancer recurrence rates by surveillance timing. RESULTS: Surveillance was inappropriate in 76% and 89% of patients diagnosed before 2002 and in 2002, respectively. Patients eligible under the pre-2002 guideline mainly received surveillance too late or were absent (57% of cases). For patients eligible under the 2002 guideline surveillance occurred mainly too early (48%). The rate of advanced neoplasia at surveillance was higher in patients with delayed surveillance compared with those with too early or appropriate timed surveillance (8% vs 4-5%, p<0.01). CONCLUSIONS: There is much room for improving surveillance practice. Less than 25% of patients with adenoma receive appropriate surveillance. Such practice seriously hampers the effectiveness and efficiency of surveillance, as too early surveillance poses a considerable burden on available resources while delayed surveillance is associated with an increased rate of advanced adenoma and especially colorectal cancer.

Ulcerative colitis patients with an inflammatory response upon mesalazine cannot be desensitized: a randomized study.

BACKGROUND AND AIMS: Mesalazine is a key drug in the treatment of ulcerative colitis (UC). Intolerance to mesalazine has been described, including fever and gastrointestinal symptoms. Several case reports reported successful desensitization of patients with mesalazine intolerance. The aim was to assess the number of UC patients who are persistently intolerant to mesalazine after single-blinded rechallenge and to test the effectiveness of a rapid desensitization protocol in UC patients demonstrated mesalazine intolerance. METHODS: This is a prospective, single-blind randomized study in UC patients who discontinued mesalazine because of intolerance. Patients with severe reactions were excluded. Eligible patients underwent a skin patch test with mesalazine followed by a single-blinded randomized crossover rechallenge with 500 mg mesalazine or placebo. Patients with symptoms upon rechallenge were admitted to the hospital for 3 days oral desensitization. RESULTS: Nine of the 37 identified UC patients who discontinued mesalazine because of intolerance were included. All nine patients had negative patch tests, seven patients had symptoms (fever, nausea, vomiting and diarrhea) within 2 h upon rechallenge. Four of these seven patients participated in the desensitization protocol and in none a successful desensitization could be performed. All four had an inflammatory intolerance reaction with rise in C-reactive protein. There were no elevations in serum tryptase or urinary-methylhistamine levels observed and no signs of immediate type allergic reactions, like urticaria, bronchial obstruction or anaphylaxis. CONCLUSION: We recommend not to rechallenge UC patients with an inflammatory response upon mesalazine and these patients will not benefit from a rapid desensitization protocol.

Features of adenoma and colonoscopy associated with recurrent colorectal neoplasia based on a large community-based study.

BACKGROUND & AIMS: We investigated adenoma and colonoscopy characteristics that are associated with recurrent colorectal neoplasia based on data from community-based surveillance practice. METHODS: We analyzed data of 2990 consecutive patients (55% male; mean age 61 years) newly diagnosed with adenomas from 1988 to 2002 at 10 hospitals throughout The Netherlands. Medical records were reviewed until December 1, 2008. We excluded patients with hereditary colorectal cancer (CRC) syndromes, a history of CRC, inflammatory bowel disease, or without surveillance data. We analyzed associations among adenoma number, size, grade of dysplasia, villous histology, and location with recurrence of advanced adenoma (AA) and nonadvanced adenoma (NAA). We performed a multivariable multinomial logistic regression analysis to estimate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: During the surveillance period, 203 (7%) patients were diagnosed with AA and 954 (32%) patients with NAA. The remaining 1833 (61%) patients had no adenomas during a median follow-up of 48 months. Factors associated with AA during the surveillance period included baseline number of adenomas (ORs ranging from 1.6 for 2 adenomas; 95% CI: 1.1-2.4 to 3.3 for ≥5 adenomas; 95% CI: 1.7-6.6), adenoma size ≥10 mm (OR = 1.7; 95% CI: 1.2-2.3), villous histology (OR = 2.0; 95% CI: 1.2-3.2), proximal location (OR = 1.6; 95% CI: 1.2-2.3), insufficient bowel preparation (OR = 3.4; 95% CI: 1.6-7.4), and only distal colonoscopy reach (OR = 3.2; 95% CI: 1.2-8.5). Adenoma number had the greatest association with NAA. High-grade dysplasia was not associated with AA or NAA. CONCLUSIONS: Large size and number, villous histology, proximal location of adenomas, insufficient bowel preparation, and poor colonoscopy reach were associated with detection of AA during surveillance based on data from community-based practice. These characteristics should be used jointly to develop surveillance policies for adenoma patients.

Dietary B vitamin and methionine intake and MTHFR C677T genotype on risk of colorectal tumors in Lynch syndrome: the GEOLynch cohort study.

PURPOSE: Dietary intake of B vitamins and methionine, essential components of DNA synthesis and methylation pathways, may influence colorectal tumor (CRT) development. The impact of B vitamins on colorectal carcinogenesis in individuals with Lynch syndrome (LS) is unknown but is important given their high lifetime risk of developing neoplasms. The role of MTHFR C677T genotype in modifying these relationships in LS individuals is also unclear. We investigated associations between dietary intakes of folate, vitamins B2, B6, B12, and methionine and CRT development in a prospective cohort study of 470 mismatch repair gene mutation carriers. METHODS: Dietary intakes were assessed by food frequency questionnaire. Cox regression models with robust sandwich covariance estimation, adjusted for age, sex, physical activity, number of colonoscopies during person-time, NSAID use, and mutual vitamins were used to calculate hazard ratios (HRs) and 95 % confidence intervals (95 % CIs). Analyses were also stratified by MTHFR C677T genotype. RESULTS: During a median person-time of 28.0 months, 131 persons developed a CRT. Fifty-one of these persons developed an incident colorectal adenoma, while there were four persons who developed an incident colorectal carcinoma. Compared to the lowest tertile of intake, adjusted HRs (95 % CIs) for CRT development in the highest tertile were 1.06 (0.59-1.91) for folate, 0.77 (0.39-1.51) for vitamin B2, 0.98 (0.59-1.62) for vitamin B6, 1.24 (0.77-2.00) for vitamin B12, and 1.36 (0.83-2.20) for methionine. Low vitamin B2 and low methionine intake were statistically significantly associated with an increased risk of CRT in MTHFR 677TT individuals compared to a combined reference of persons with low intake and CC genotype. CONCLUSIONS: There was no suggestion that intake of any dietary B vitamin or methionine was associated with CRT development among those with LS.

Targeting FLIP and Mcl-1 using a combination of aspirin and sorafenib sensitizes colon cancer cells to TRAIL.

The multikinase inhibitor sorafenib is highly effective against certain types of cancer in the clinic and prevents colon cancer cell proliferation in vitro. Non-steroidal anti-inflammatory drugs, such as acetylsalicylic acid (aspirin), have shown activity against colon cancer cells. The aims of this study were to determine whether the combination of aspirin with sorafenib has enhanced anti-proliferative effects and increases recombinant human tumour necrosis factor-related apoptosis-inducing ligand (rhTRAIL)-induced apoptosis in the human SW948, Lovo, Colo205, Colo320, Caco-2 and HCT116 colon cancer cell lines. In four cell lines, aspirin strongly stimulated the anti-proliferative effects of sorafenib (∼four-fold enhancement) by inducing cell cycle arrest. Furthermore, combining low doses of aspirin (≤ 5 mm) and sorafenib (≤ 2.5 µm) greatly sensitized TRAIL-sensitive and TRAIL-resistant colon cancer cells to rhTRAIL, much more potently than either drug combined with rhTRAIL. The increase in rhTRAIL sensitivity was due to inhibition of FLIP and Mcl-1 protein expression following aspirin and sorafenib co-treatment, as confirmed by knock-down studies. Next, the clinical relevance of targeting FLIP and Mcl-1 in colon cancer was examined. Using immunohistochemistry, we found that Mcl-1 expression was significantly increased in colon adenoma and carcinoma patient material compared to healthy colonic epithelium, similar to the enhanced FLIP expression we recently observed in colon cancer. These results underscore the potential of combining low doses of aspirin with sorafenib to inhibit proliferation and target the anti-apoptotic proteins FLIP and Mcl-1 in colon cancer cells.

Dietary patterns and colorectal adenomas in Lynch syndrome: the GEOLynch cohort study.

BACKGROUND: Patients with Lynch syndrome (LS) have a high risk of developing colorectal cancer due to mutations in mismatch repair genes. Because dietary factors, alone and in combination, influence sporadic colorectal carcinogenesis, the association of dietary patterns with colorectal adenomas in LS patients was assessed. METHODS: In the GEOLynch cohort of 486 persons with LS, dietary information was collected, using a food frequency questionnaire. Dietary pattern scores were obtained by principal components analysis. Hazard ratios (HR) between dietary patterns and colorectal adenomas were calculated using Cox regression models. Robust sandwich variance estimates were used to control for dependency within families. Final models were adjusted for age, sex, smoking habits, colorectal adenoma history, and extent of colon resection. RESULTS: During a median follow-up of 20 months, colorectal adenomas were detected in 58 persons. Four dietary patterns were identified: a "Prudent," "Meat," "Snack," and "Cosmopolitan" pattern. Individuals within the highest tertile of the "Prudent" pattern had a HR of 0.73 (95% confidence interval [CI], 0.32-1.66) for colorectal adenomas, compared with the lowest tertile. Those with high "Meat" pattern scores had a HR of 1.70 (95% CI, 0.83-3.52). A high "Snack" pattern was associated with an increased risk of colorectal adenomas (HR, 2.16; 95% CI, 1.03-4.49). A HR of 1.25 (95% CI, 0.61-2.55) was observed for persons in the highest tertile of the "Cosmopolitan" pattern. CONCLUSIONS: These findings suggest that dietary patterns may be associated with development of colorectal adenoma in patients with Lynch syndrome. The directions of these findings are corroborative with those observed in studies investigating sporadic colorectal cancer.

Smoking increases the risk for colorectal adenomas in patients with Lynch syndrome.

BACKGROUND & AIMS: Individuals with Lynch syndrome have a high risk of developing colorectal carcinomas and adenomas at a young age, due to inherited mutations in mismatch repair genes. We investigated whether modifiable lifestyle factors, such as smoking and alcohol intake, increase this risk. METHODS: Using data from the GeoLynch cohort study, a prospective analysis of 386 subjects with Lynch syndrome, we calculated hazard ratios for the association between smoking and alcohol intake and development of colorectal adenoma. We used robust variance estimates in the calculation of 95% confidence intervals to account for dependency within families and adjusted for confounding by age, sex, smoking (in the analyses of alcohol intake), number of colonoscopies during the follow-up, colonic resection, and body mass index. RESULTS: During a median follow-up of 10 months, 58 subjects developed a histologically confirmed colorectal adenoma. The hazard ratio for current smokers was 6.13 (95% confidence interval, 2.84-13.22) and for former smokers was 3.03 (95% confidence interval, 1.49-6.16) compared with never smokers. Among ever smokers, a higher number of pack-years was associated with an increased risk for colorectal adenoma (P for trend = .03). There was a trend of alcohol intake increasing the risk of colorectal adenomas, although this was not statistically significant; the hazard ratio for the highest tertile of intake (median, 22 g/day) vs the lowest tertile (median, 0.4 g/day) was 1.56 (95% confidence interval, 0.71-3.43). CONCLUSIONS: Among people with Lynch syndrome, current smokers have an increased risk of colorectal adenomas. Former smokers have a lower risk than current smokers, but greater risk than never smokers. Individuals with Lynch syndrome should be encouraged to avoid smoking.

Quality of life after surgery for colon cancer in patients with Lynch syndrome: partial versus subtotal colectomy.

BACKGROUND: Lynch syndrome is a disorder caused by mismatch repair gene mutations. Mutation carriers have a high risk of developing colorectal cancer. In patients with Lynch syndrome in whom colon cancer has been diagnosed, in general, subtotal colectomy instead of partial colectomy is recommended because of the substantial risk of metachronous colorectal cancer. However, the effect of more extensive surgery on quality of life and functional outcome is unknown. OBJECTIVE: The aim of this study was to investigate quality of life and functional outcome in patients with Lynch syndrome after partial colectomy and subtotal colectomy. DESIGN: This is a nationwide cross-sectional study in the Netherlands. SETTINGS: Two quality-of-life questionnaires (Short Form-36 and The European Organization for Research and Treatment of Cancer Colorectal Cancer-specific Quality of Life Questionnaire Module) and a functional outcome questionnaire (Colorectal Functional Outcome) were used. PATIENTS: Patients with Lynch syndrome who underwent surgery for colon cancer were included. MAIN OUTCOME MEASURES: The primary outcomes measured were quality of life and functional outcome. RESULTS: Questionnaires were sent to 192 patients with Lynch syndrome who underwent surgery for colorectal cancer. A total of 136 patients returned the questionnaire (response rate, 71%). Eighteen patients with rectal cancer, 9 patients with a permanent ileostomy, and 5 patients with an IPAA were excluded. Fifty-one patients underwent partial colectomy, and 53 underwent subtotal colectomy. None of the scales of the Short Form-36 survey showed a significant difference. Analysis of the Colorectal Functional Outcome questionnaire revealed that, after subtotal colectomy, patients have a significantly higher stool frequency (p ≤ 0.01) and a significantly higher score on stool-related aspects (p = 0.06) and social impact (p = 0.03). The European Organization for Research and Treatment of Cancer Colorectal Cancer-specific Quality of Life Questionnaire Module presented more problems with defecation after subtotal colectomy (p ≤ 0.01). LIMITATIONS: Certain selection bias cannot be ruled out. CONCLUSIONS: Although functional outcome is worse after subtotal colectomy than after partial colectomy, generic quality of life does not differ after the 2 types of surgery in Lynch syndrome. When discussing the options for surgery with the patient, all advantages and disadvantages of both surgical procedures, including quality of life and functional outcome, should be discussed.

TNF-related apoptosis-inducing ligand cooperates with NSAIDs via activated Wnt signalling in (pre)malignant colon cells.

TNF-related apoptosis-inducing ligand (TRAIL) receptor agonistic agents and non-steroidal anti-inflammatory drugs (NSAIDs) are interesting agents for the chemoprevention and treatment of colorectal cancer. We investigated whether NSAIDs sensitize colon cancer and adenoma cell lines and ex vivo cultured human adenomas to recombinant human (rh)TRAIL. Involvement of the crucial Wnt signalling pathway in the sensitization of colon cancer cells was examined. Five colon cancer and two adenoma cell lines, human ex vivo adenomas and normal colonic epithelium were treated with aspirin or sulindac combined with rhTRAIL. Apoptosis levels, expression of intracellular proteins and TRAIL receptor membrane expression were assessed. Ls174T cells stably transfected with an inducible dominant negative TCF-4 (dnTCF-4) construct served to analyse the role of Wnt pathway activation. Both rhTRAIL-sensitive and -resistant colon cancer cell lines were strongly sensitized to rhTRAIL by aspirin (maximum enhancement ratio, 7.1). Remarkably, in adenoma cell lines sulindac enhanced rhTRAIL-induced apoptosis most effectively (maximum enhancement ratio, 2.5). Although membrane TRAIL receptor expression was not affected by NSAIDs, caspase-8 activation was enhanced by combinational treatment. Several proteins from different biological pathways were affected by NSAIDs, indicating complex mechanisms of sensitization. Elimination of TCF-4 completely blocked the sensitizing effect in colon cancer cells. In ex vivo adenomas the combination of sulindac and rhTRAIL increased apoptosis from 18.4% (sulindac) and 17.8% (rhTRAIL) to 28.0% (p = 0.003 and p = 0.005, respectively). It was concluded that NSAID-induced sensitization to rhTRAIL requires TCF-4 activity. Thus, the combination of TRAIL-receptor agonistic agents and NSAIDs is a potentially attractive treatment option for (pre)malignant tumours with constitutively active Wnt signalling, such as colorectal tumours.

Playing the DISC: turning on TRAIL death receptor-mediated apoptosis in cancer.

Formation of the pro-apoptotic death-inducing signaling complex (DISC) can be initiated in cancer cells via binding of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to its two pro-apoptotic receptors, TRAIL receptor 1 (TRAIL-R1) and TRAIL-R2. Primary components of the DISC are trimerized TRAIL-R1/-R2, FADD, caspase 8 and caspase 10. The anti-apoptotic protein FLIP can also be recruited to the DISC to replace caspase 8 and form an inactive complex. Caspase 8/10 processing at the DISC triggers the caspase cascade, which eventually leads to apoptotic cell death. Besides TRAIL, TRAIL-R1- or TRAIL-R2-selective variants of TRAIL and agonistic antibodies have been designed. These ligands are of interest as anti-cancer agents since they selectively kill tumor cells. To increase tumor sensitivity to TRAIL death receptor-mediated apoptosis and to overcome drug resistance, TRAIL receptor ligands have already been combined with various therapies in preclinical models. In this review, we discuss factors influencing the initial steps of the TRAIL apoptosis signaling pathway, focusing on mechanisms modulating DISC assembly and caspase activation at the DISC. These insights will direct rational design of drug combinations with TRAIL receptor ligands to maximize DISC signaling.

One to 2-year surveillance intervals reduce risk of colorectal cancer in families with Lynch syndrome.

BACKGROUND & AIMS: Two percent to 4% of all cases of colorectal cancer (CRC) are associated with Lynch syndrome. Dominant clustering of CRC (non-Lynch syndrome) accounts for 1%-3% of the cases. Because carcinogenesis is accelerated in Lynch syndrome, an intensive colonoscopic surveillance program has been recommended since 1995. The aim of the study was to evaluate the effectiveness of this program. METHODS: The study included 205 Lynch syndrome families with identified mutations in one of the mismatch repair genes (745 mutation carriers). We also analyzed data from non-Lynch syndrome families (46 families, 344 relatives). Patients were observed from January 1, 1995, until January 1, 2009. End points of the study were CRC or date of the last colonoscopy. RESULTS: After a mean follow-up of 7.2 years, 33 patients developed CRC under surveillance. The cumulative risk of CRC was 6% after the 10-year follow-up period. The risk of CRC was higher in carriers older than 40 years and in carriers of MLH1 and MSH2 mutations. After a mean follow-up of 7.0 years, 6 cases of CRC were detected among non-Lynch syndrome families. The risk of CRC was significantly higher among families with Lynch syndrome, compared with those without. CONCLUSIONS: With surveillance intervals of 1-2 years, members of families with Lynch syndrome have a lower risk of developing CRC than with surveillance intervals of 2-3 years. Because of the low risk of CRC in non-Lynch syndrome families, a less intensive surveillance protocol can be recommended.

Cytomegalovirus infection increases the risk for inflammatory bowel disease.

This letter discusses the paper by Onyeagocha et al published in the November 2009 issue of the AJP.

Chromosome 8q23.3 and 11q23.1 variants modify colorectal cancer risk in Lynch syndrome.

BACKGROUND & AIMS: Recent genome-wide association studies have identified common low-risk variants for colorectal cancer (CRC). To assess whether these influence CRC risk in the Lynch syndrome, we genotyped these variants in a large series of proven mutation carriers. METHODS: We studied 675 individuals from 127 different families from the Dutch Lynch syndrome Registry whose mutation carrier status was known. We genotyped 8q24.21, 8q23.3, 10p14, 11q23.1, 15q13.3, and 18q21.1 variants in carriers of a mismatch repair gene mutation. Univariate and multivariate analysis was used to analyse the association between the presence of a risk variant and CRC risk. RESULTS: A significant association was found between CRC risk and rs16892766 (8q23.3) and rs3802842 (11q23.1). For rs16892766, possession of the C-allele was associated with an elevated risk of CRC in a dose-dependent fashion, with homozygosity for CC being associated with a 2.16-fold increased risk. For rs3802842, the increased risk of CRC associated with the C-allele was only found among female carriers, while CRC risk was substantially higher among homozygous (hazard ratio [HR] 3.08) than among heterozygous carriers of the C-allele (HR 1.49). In an additive model of both variants, the risk was significantly associated with the number of risk alleles (HR 1.60 for carriers of 2 or more risk alleles). The effects were stronger in female carriers than in male carriers. CONCLUSION: We have identified 2 loci that are significantly associated with CRC risk in Lynch syndrome families. These modifiers may be helpful in identifying high-risk individuals who require more intensive surveillance.

Differences in genetic background between active smokers, passive smokers, and non-smokers with Crohn's disease.

OBJECTIVES: Smoking behavior and genetic variations are important factors for the development of Crohn's disease (CD), but studies investigating the interaction between smoking and genetic background are scarce. We studied allelic associations of 19 confirmed variants located in 14 CD-associated genes or loci, in CD patients stratified for active smoking at diagnosis and passive smoking in childhood. METHODS: Genotyping data of 19 CD-associated single-nucleotide polymorphisms (SNPs) were available for 310 CD patients and 976 controls. Data on active smoking at diagnosis and passive smoking in childhood were obtained through a written questionnaire and a review of medical charts. RESULTS: The loci associated in smoking, but not in non-smoking, CD patients were 5p13.1 (rs17234657), DLG5 (rs2165047), NKX2-3 (rs10883365), and NOD2 (R702W). The loci associated in non-smoking, but not in smoking, CD patients were IL23R (rs7517847), 5p13.1 (rs9292777), IRGM (rs13361189 and rs4958847), IL12B (rs6887695), and CCNY (rs3936503). PTPN2 (rs2542151) was only associated in the smoking CD cohort (P=0.041), and not in the entire cohort (P=0.23) or in the non-smoking CD cohort (P=0.80). In passively smoking CD patients, associations with 13 SNPs in 9 loci were found, including PTPN2. In non-passive smoking CD patients, only associations with NOD2 (1007fsinsC and G908R) were found. CONCLUSIONS: The difference in associated genes between smoking and non-smoking CD patients implies a complex gene-environment interaction. Therefore, genetic studies of CD should be stratified for smoking behavior, as otherwise moderately associated genes such as PTPN2 can be missed.

Low-volume PEG plus ascorbic acid versus high-volume PEG as bowel preparation for colonoscopy.

OBJECTIVE: High volumes of polyethylene glycol (PEG)-based solutions as bowel preparation for colonoscopy are effective, but often poorly tolerated. To compare a 2 l PEG-based solution combined with ascorbic acid (PEG + Asc) with 4 l PEG-based solution (PEG). METHODS: In a single blind, quasi-randomized, prospective study, 350 patients undergoing colonoscopy received 2 l of PEG + Asc or 4 l of PEG. For morning procedures, the total dose of PEG + Asc was taken the evening before, for afternoon colonoscopies, PEG + Asc was given as a split dose. The 4 l PEG preparation was given as a split dose. Efficacy of preparation was scored on a five-point scale in three different colon segments. Patients' experiences were evaluated using a questionnaire. RESULTS: From 307 patients (149 PEG + Asc, 158 PEG), results were available. Successful colon cleansing was achieved in 90.6% in the PEG + Asc group compared to 96% in the PEG group (not significant). In patients prepared with PEG + Asc, bowel cleansing was worse when patients underwent colonoscopy in the morning, compared to afternoon procedures. Side-effects and patients' experiences were similar in the PEG + Asc and PEG group. CONCLUSIONS: Low-volume PEG + ascorbic acid has comparable efficacy and tolerability as high-volume PEG solution. The cleansing results were worse if patients received the full dose PEG + Asc the evening before the procedure compared to the split dose. Our data support the administration of PEG + Asc as a split dose before the procedure.

Mononucleotide precedes dinucleotide repeat instability during colorectal tumour development in Lynch syndrome patients.

A progressive accumulation of genetic alterations underlies the adenoma-carcinoma sequence of colorectal cancer. This accumulation of mutations is driven by genetic instability, of which there are different types. Microsatellite instability (MSI) is the predominant type present in the tumours of Lynch syndrome patients and in a subset of sporadic tumours. It is generally accepted that MSI can be found in the early stages of tumour progression, such as adenomas; however, the frequencies reported vary widely among studies. Moreover, data on the qualitative differences between adenomas and carcinomas, or between tumours of hereditary and sporadic origin, are scarce. We compared MSI in samples of colorectal adenoma and colorectal carcinoma in order to identify possible differences along the adenoma-carcinoma sequence. We compared germline mismatch repair (MMR) gene mutation carriers and non-carriers, to address possible differences of instability patterns between Lynch syndrome patients and patients with sporadic tumours. We found a comparable relative frequency of mono- and dinucleotide instability in sporadic colorectal adenomas and carcinomas, dinucleotide instability being observed most frequently in these sporadic tumours. In MMR gene truncating mutation carriers, the profile was different: colorectal adenomas showed predominantly mononucleotide instability and in colorectal carcinomas, also more mononucleotide than dinucleotide instability was detected. We conclude that MSI profiles differ between sporadic and Lynch syndrome tumours, and that mononucleotide marker instability precedes dinucleotide marker instability during colorectal tumour development in Lynch syndrome patients. As mononucleotide MSI proves to be highly sensitive for detecting mutation carriers, we propose the use of mononucleotide markers for the identification of possible Lynch syndrome patients.