Huw Thomas

Guidelines for colorectal cancer screening and surveillance in moderate and high risk groups (update from 2002)

The British Society of Gastroenterology (BSG) and the Association of Coloproctology for Great Britain and Ireland (ACPGBI) commissioned this update of the 2002 guidance. The aim, as before, is to provide guidance on the appropriateness, method and frequency of screening for people at moderate and high risk from colorectal cancer. This guidance provides some new recommendations for those with inflammatory bowel disease and for those at moderate risk resulting from a family history of colorectal cancer. In other areas guidance is relatively unchanged, but the recent literature was reviewed and is included where appropriate.

Long-term effect of aspirin on cancer risk in carriers of hereditary colorectal cancer: an analysis from the CAPP2 randomised controlled trial

Summary Background Observational studies report reduced colorectal cancer in regular aspirin consumers. Randomised controlled trials have shown reduced risk of adenomas but none have employed prevention of colorectal cancer as a primary endpoint. The CAPP2 trial aimed to investigate the antineoplastic effects of aspirin and a resistant starch in carriers of Lynch syndrome, the major form of hereditary colorectal cancer; we now report long-term follow-up of participants randomly assigned to aspirin or placebo. Methods In the CAPP2 randomised trial, carriers of Lynch syndrome were randomly assigned in a two-by-two factorial design to 600 mg aspirin or aspirin placebo or 30 g resistant starch or starch placebo, for up to 4 years. Randomisation was in blocks of 16 with provision for optional single-agent randomisation and extended postintervention double-blind follow-up; participants and investigators were masked to treatment allocation. The primary endpoint was development of colorectal cancer. Analysis was by intention to treat and per protocol. This trial is registered, ISRCTN59521990. Results 861 participants were randomly assigned to aspirin or aspirin placebo. At a mean follow-up of 55·7 months, 48 participants had developed 53 primary colorectal cancers (18 of 427 randomly assigned to aspirin, 30 of 434 to aspirin placebo). Intention-to-treat analysis of time to first colorectal cancer showed a hazard ratio (HR) of 0·63 (95% CI 0·35–1·13, p=0·12). Poisson regression taking account of multiple primary events gave an incidence rate ratio (IRR) of 0·56 (95% CI 0·32–0·99, p=0·05). For participants completing 2 years of intervention (258 aspirin, 250 aspirin placebo), per-protocol analysis yielded an HR of 0·41 (0·19–0·86, p=0·02) and an IRR of 0·37 (0·18–0·78, p=0·008). No data for adverse events were available postintervention; during the intervention, adverse events did not differ between aspirin and placebo groups. Interpretation 600 mg aspirin per day for a mean of 25 months substantially reduced cancer incidence after 55·7 months in carriers of hereditary colorectal cancer. Further studies are needed to establish the optimum dose and duration of aspirin treatment. Funding European Union; Cancer Research UK; Bayer Corporation; National Starch and Chemical Co; UK Medical Research Council; Newcastle Hospitals trustees; Cancer Council of Victoria Australia; THRIPP South Africa; The Finnish Cancer Foundation; SIAK Switzerland; Bayer Pharma.

Germline mutations affecting the proofreading domains of POLE and POLD1 predispose to colorectal adenomas and carcinomas

Many individuals with multiple or large colorectal adenomas or early-onset colorectal cancer (CRC) have no detectable germline mutations in the known cancer predisposition genes. Using whole-genome sequencing, supplemented by linkage and association analysis, we identified specific heterozygous POLE or POLD1 germline variants in several multiple-adenoma and/or CRC cases but in no controls. The variants associated with susceptibility, POLE p.Leu424Val and POLD1 p.Ser478Asn, have high penetrance, and POLD1 mutation was also associated with endometrial cancer predisposition. The mutations map to equivalent sites in the proofreading (exonuclease) domain of DNA polymerases ɛ and δ and are predicted to cause a defect in the correction of mispaired bases inserted during DNA replication. In agreement with this prediction, the tumors from mutation carriers were microsatellite stable but tended to acquire base substitution mutations, as confirmed by yeast functional assays. Further analysis of published data showed that the recently described group of hypermutant, microsatellite-stable CRCs is likely to be caused by somatic POLE mutations affecting the exonuclease domain.

Guidelines for the clinical management of familial adenomatous polyposis (FAP)

Background: Familial adenomatous polyposis (FAP) is a well-described inherited syndrome, which is responsible for <1% of all colorectal cancer (CRC) cases. The syndrome is characterised by the development of hundreds to thousands of adenomas in the colorectum. Almost all patients will develop CRC if they are not identified and treated at an early stage. The syndrome is inherited as an autosomal dominant trait and caused by mutations in the APC gene. Recently, a second gene has been identified that also gives rise to colonic adenomatous polyposis, although the phenotype is less severe than typical FAP. The gene is the MUTYH gene and the inheritance is autosomal recessive. In April 2006 and February 2007, a workshop was organised in Mallorca by European experts on hereditary gastrointestinal cancer aiming to establish guidelines for the clinical management of FAP and to initiate collaborative studies. Thirty-one experts from nine European countries participated in these workshops. Prior to the meeting, various participants examined the most important management issues according to the latest publications. A systematic literature search using Pubmed and reference lists of retrieved articles, and manual searches of relevant articles, was performed. During the workshop, all recommendations were discussed in detail. Because most of the studies that form the basis for the recommendations were descriptive and/or retrospective in nature, many of them were based on expert opinion. The guidelines described herein may be helpful in the appropriate management of FAP families. In order to improve the care of these families further, prospective controlled studies should be undertaken.

Revised guidelines for the clinical management of Lynch syndrome (HNPCC): recommendations by a group of European experts

Lynch syndrome (LS) is characterised by the development of colorectal cancer, endometrial cancer and various other cancers, and is caused by a mutation in one of the mismatch repair genes: MLH1, MSH2, MSH6 or PMS2. In 2007, a group of European experts (the Mallorca group) published guidelines for the clinical management of LS. Since then substantial new information has become available necessitating an update of the guidelines. In 2011 and 2012 workshops were organised in Palma de Mallorca. A total of 35 specialists from 13 countries participated in the meetings. The first step was to formulate important clinical questions. Then a systematic literature search was performed using the Pubmed database and manual searches of relevant articles. During the workshops the outcome of the literature search was discussed in detail. The guidelines described in this paper may be helpful for the appropriate management of families with LS. Prospective controlled studies should be undertaken to improve further the care of these families.

Peutz–Jeghers syndrome: a systematic review and recommendations for management

Peutz–Jeghers syndrome (PJS, MIM175200) is an autosomal dominant condition defined by the development of characteristic polyps throughout the gastrointestinal tract and mucocutaneous pigmentation. The majority of patients that meet the clinical diagnostic criteria have a causative mutation in the STK11 gene, which is located at 19p13.3. The cancer risks in this condition are substantial, particularly for breast and gastrointestinal cancer, although ascertainment and publication bias may have led to overestimates in some publications. Current surveillance protocols are controversial and not evidence-based, due to the relative rarity of the condition. Initially, endoscopies are more likely to be done to detect polyps that may be a risk for future intussusception or obstruction rather than cancers, but surveillance for the various cancers for which these patients are susceptible is an important part of their later management. This review assesses the current literature on the clinical features and management of the condition, genotype–phenotype studies, and suggested guidelines for surveillance and management of individuals with PJS. The proposed guidelines contained in this article have been produced as a consensus statement on behalf of a group of European experts who met in Mallorca in 2007 and who have produced guidelines on the clinical management of Lynch syndrome and familial adenomatous polyposis.

Meta-analysis of three genome-wide association studies identifies susceptibility loci for colorectal cancer at 1q41, 3q26.2, 12q13.13 and 20q13.33

Genome-wide association studies (GWAS) have identified ten loci harboring common variants that influence risk of developing colorectal cancer (CRC). To enhance the power to identify additional CRC risk loci, we conducted a meta-analysis of three GWAS from the UK which included a total of 3,334 affected individuals (cases) and 4,628 controls followed by multiple validation analyses including a total of 18,095 cases and 20,197 controls. We identified associations at four new CRC risk loci: 1q41 (rs6691170, odds ratio (OR) = 1.06, P = 9.55 × 10−10 and rs6687758, OR = 1.09, P = 2.27 × 10−9), 3q26.2 (rs10936599, OR = 0.93, P = 3.39 × 10−8), 12q13.13 (rs11169552, OR = 0.92, P = 1.89 × 10−10 and rs7136702, OR = 1.06, P = 4.02 × 10−8) and 20q13.33 (rs4925386, OR = 0.93, P = 1.89 × 10−10). In addition to identifying new CRC risk loci, this analysis provides evidence that additional CRC-associated variants of similar effect size remain to be discovered.

Common genetic variants at the CRAC1 (HMPS) locus on chromosome 15q13.3 influence colorectal cancer risk

We mapped a high-penetrance gene (CRAC1; also known as HMPS) associated with colorectal cancer (CRC) in the Ashkenazi population to a 0.6-Mb region on chromosome 15 containing SCG5 (also known as SGNE1), GREM1 and FMN1. We hypothesized that the CRAC1 locus harbored low-penetrance variants that increased CRC risk in the general population. In a large series of colorectal cancer cases and controls, SNPs near GREM1 and SCG5 were strongly associated with increased CRC risk (for rs4779584, P = 4.44 × 10−14).

Total colonic dye-spray increases the detection of diminutive adenomas during routine colonoscopy: A randomized controlled trial

BACKGROUND Small adenomas may be missed during colonoscopy, but chromoscopy has been reported to enhance detection. The aim of this randomized-controlled trial was to determine the effect of total colonic dye spray on adenoma detection during routine colonoscopy. METHODS Consecutive outpatients undergoing routine colonoscopy were randomized to a dye-spray group (0.1% indigo carmine used to coat the entire colon during withdrawal from the cecum) or control group (no dye). RESULTS Two hundred fifty-nine patients were randomized, 124 to the dye-spray and 135 to the control group; demographics, indication for colonoscopy, and quality of the preparation were similar between the groups. Extubation from the cecum took a median of 9:05 minutes (range: 2:48-24:44 min) in the dye-spray group versus 4:52 minutes (range: 1:42-15:21 min) in the control group (p < 0.0001). The proportion of patients with at least 1 adenoma and the total number of adenomas were not different between groups. However, in the dye-spray group significantly more diminutive adenomas (<5 mm) were detected proximal to the sigmoid colon (p = 0.026) and more patients were identified with 3 or more adenomas (p = 0.002). More non-neoplastic polyps were detected throughout the colon in the dye-spray group (p = 0.003). There were no complications. CONCLUSIONS Dye-spray increases the detection of small adenomas in the proximal colon and patients with multiple adenomas, but long-term outcomes should be studied to determine the clinical value of these findings.

Effect of Aspirin or Resistant Starch on Colorectal Neoplasia in the Lynch Syndrome

BACKGROUND Observational and epidemiologic data indicate that the use of aspirin reduces the risk of colorectal neoplasia; however, the effects of aspirin in the Lynch syndrome (hereditary nonpolyposis colon cancer) are not known. Resistant starch has been associated with an antineoplastic effect on the colon. METHODS In a randomized, placebo-controlled trial, we used a two-by-two design to investigate the effects of aspirin, at a dose of 600 mg per day, and resistant starch (Novelose), at a dose of 30 g per day, in reducing the risk of adenoma and carcinoma among persons with the Lynch syndrome. RESULTS Among 1071 persons in 43 centers, 62 were ineligible to participate in the study, 72 did not enter the study, and 191 withdrew from the study. These three categories were equally distributed across the study groups. Over a mean period of 29 months (range, 7 to 74), colonic adenoma or carcinoma developed in 141 participants. Of 693 participants randomly assigned to receive aspirin or placebo, neoplasia developed in 66 participants receiving aspirin (18.9%), as compared with 65 receiving placebo (19.0%) (relative risk, 1.0; 95% confidence interval [CI], 0.7 to 1.4). There were no significant differences between the two groups with respect to the development of advanced neoplasia (7.4% and 9.9%, respectively; P=0.33). Among the 727 participants receiving resistant starch or placebo, neoplasia developed in 67 participants receiving starch (18.7%), as compared with 68 receiving placebo (18.4%) (relative risk, 1.0; 95% CI, 0.7 to 1.4). Advanced adenomas and colorectal cancers were evenly distributed in the two groups. The prevalence of serious adverse events was low, and the events were evenly distributed. CONCLUSIONS The use of aspirin, resistant starch, or both for up to 4 years has no effect on the incidence of colorectal adenoma or carcinoma among carriers of the Lynch syndrome. (Current Controlled Trials number, ISRCTN59521990.)