Marie Luise Bisgaard

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.

Clinical findings with implications for genetic testing in families with clustering of colorectal cancer.

BACKGROUND Germ-line mutations in DNA mismatch-repair genes (MSH2, MLH1, PMS1, PMS2, and MSH6) cause susceptibility to hereditary nonpolyposis colorectal cancer. We assessed the prevalence of MSH2 and MLH1 mutations in families suspected of having hereditary nonpolyposis colorectal cancer and evaluated whether clinical findings can predict the outcome of genetic testing. METHODS We used denaturing gradient gel electrophoresis to identify MSH2 and MLH1 mutations in 184 kindreds with familial clustering of colorectal cancer or other cancers associated with hereditary nonpolyposis colorectal cancer. Information on the site of cancer, the age at diagnosis, and the number of affected family members was obtained from all families. RESULTS Mutations of MSH2 or MLH1 were found in 47 of the 184 kindreds (26 percent). Clinical factors associated with these mutations were early age at diagnosis of colorectal cancer, the occurrence in the kindred of endometrial cancer or tumors of the small intestine, a higher number of family members with colorectal or endometrial cancer, the presence of multiple colorectal cancers or both colorectal and endometrial cancers in a single family member, and fulfillment of the Amsterdam criteria for the diagnosis of hereditary nonpolyposis colorectal cancer (at least three family members in two or more successive generations must have colorectal cancer, one of whom is a first-degree relative of the other two; cancer must be diagnosed before the age of 50 in at least one family member; and familial adenomatous polyposis must be ruled out). Multivariate analysis showed that a younger age at diagnosis of colorectal cancer, fulfillment of the Amsterdam criteria, and the presence of endometrial cancer in the kindred were independent predictors of germ-line mutations of MSH2 or MLH1. These results were used to devise a logistic model for estimating the likelihood of a mutation in MSH2 and MLH1. CONCLUSIONS Assessment of clinical findings can improve the rate of detection of mutations of DNA mismatch-repair genes in families suspected of having hereditary nonpolyposis colorectal cancer.

Attenuated familial adenomatous polyposis (AFAP). A review of the literature.

Over the last decade, a subset of familial adenomatous polyposis(FAP) patients with a milder course of disease termed attenuated familial adenomatous polyposis (AFAP) has been described. AFAP is not well-defined as a disease entity – the reports on AFAP are largely casuistic or only deal with a few kindreds – and the diagnostic criteria and methods of investigation differ markedly. The true incidence and frequency of AFAP is not known. The mutations in APC associated with AFAP have mainly been detected in three parts of the gene: in the 5′ end (the first five exons), in exon 9 and in the distal 3′ end. The main features of AFAP are 100 or less colorectal adenomas with a tendency to rectal sparing, a delay in onset of adenomatosis and bowel symptoms of 20–25 years, a delay in onset of colorectal cancer (CRC) of 10–20 years and death from CRC of 15–20 years, and although the lifetime penetrance of CRC appears to be high, CRC does not seem to develop in nearly all affected patients. A more limited expression of the extracolonic features is seen, but gastric and duodenal adenomas are frequently encountered. Colonoscopy is preferred to sigmoidoscopy, should begin at the age of 20–25 years and no upper age limit of stopping surveillance is justified. Regular esophago-gastro-duodenoscopy (EGD) is recommended. Until further research has provided us with a more substantiated knowledge about AFAP changes in current surveillance and treatment are not recommended. Prophylactic colectomy with ileorectal anastomosis (IRA) is recommended in most patients.

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.)

Suspected hereditary nonpolyposis colorectal cancer : international collaborative group on hereditary non-polyposis colorectal cancer (ICG-HNPCC) criteria and results of genetic diagnosis

PURPOSE: The aim of this study was to determine the frequency of mutations in the mismatch repair genes in families suspected of having hereditary nonpolyposis colorectal cancer. METHODS: We devised two criteria for families suspected of having hereditary nonpolyposis colorectal cancer (Criteria I and II). Criteria I consist of at least two first-degree relatives affected with colorectal cancer with at least one of the following: development of multiple colorectal tumors including adenomatous polyp, at least one colorectal cancer case diagnosed before the age of 50, and occurrence of a hereditary nonpolyposis colorectal cancer extracolonic cancer (endometrium, urinary tract, small intestine, stomach, hepatobiliary system, or ovary) in family members. Criteria II consist of one colorectal cancer patient with at least one of the following: early age of onset (<40 years); endometrial, urinary tract, or small intestine cancer in the index patient or a sibling (one aged <50 years); and two siblings with other integral hereditary nonpolyposis colorectal cancer extracolonic cancers (one aged <50 years). A questionnaire was mailed to members of the International Collaborative Group on Hereditary Non-Polyposis Colorectal Cancer to determine the mutation detection rate in mismatch repair genes from the families fulfilling these criteria. For comparison the mutation detection rate for families fulfilling the Amsterdam hereditary nonpolyposis colorectal cancer criteria in each institution was also obtained. RESULTS: Data were obtained from eight different institutions (in 7 different countries). In a total of 123 patients from 123 families (67 families fulfilling Criteria I and 56 families fulfilling Criteria II), genetic testing for germline mismatch repair gene variants was performed. Germline mutations of the hMLH1 or hMSH2 genes were identified in 24 families (20 percent). Of these, the mutation detection rate for families fulfilling Criteria I was 28 percent (19/67). The mutation detection rate for families fulfilling Criteria II was 9 percent (5/56). In these eight institutions, the overall mutation detection rate for families fulfilling the Amsterdam hereditary nonpolyposis colorectal cancer criteria was 50 percent (77/154). CONCLUSION: The Criteria I for suspected hereditary nonpolyposis colorectal cancer have the advantages that they can be applied to nuclear families and they can include extracolonic cancers. The results of this study suggest that families fulfilling Criteria I should be offered genetic testing. The relatively low mutation detection rate in those families fulfilling Criteria II suggests that, using current techniques, genetic testing in these families is not practical.

Reduced Frequency of Extracolonic Cancers in Hereditary Nonpolyposis Colorectal Cancer Families with Monoallelic hMLH1 Expression

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant disease caused by mutations in one of at least four different DNA mismatch repair genes, hMLH1, hMSH2, hPMS1, and hPMS2. Phenotypically, HNPCC is characterized by the early onset of colorectal cancers and various extracolonic cancers. Depending on the presence or absence of extracolonic tumors, HNPCG-has been divided into two syndromes (Lynch syndrome I and Lynch syndrome II), but, so far, no correlation to distinct genotypes has been demonstrated. In this study, we present a frequent hMLH1 intron 14 founder mutation that is associated with a highly reduced frequency of extracolonic tumors. The mutation disrupts the splice donor site and silences the mutated allele. Tumors exhibited microsatellite instability, and loss of the wild-type hMLH1 allele was prevalent. We propose that the mutation results in a milder phenotype, because the mutated hMLH1 protein is prevented from exerting a dominant negative effect on the concerted action of the mismatch repair system.

Suspected HNPCC and Amsterdam criteria II: evaluation of mutation detection rate, an international collaborative study

Abstract. Background and aims: The Korean Hereditary Tumor Registry has proposed criteria for suspected hereditary nonpolyposis colorectal cancer (S-HNPCC criteria I and II) and confirmed their validity in an international collaborative study. The S-HNPCC criteria included families that did not fulfill the Amsterdam criteria, but in whom HNPCC was nevertheless strongly suspected. The S-HNPCC criteria was also revised accordingly since some S-HNPCC families now fullfil the revised Amsterdam criteria. The original Amsterdam criteria have recently been revised, including some extracolonic cancers. This study compared the mutation detection rates between the revised and previous Amsterdam and S-HNPCC criteria. Patients and methods: Data on the mutational status of 393 HNPCC suspected families were collected from ten different institutes. Two hundred families were categorized into old S-HNPCC criteria (142 into criteria I and 58 into criteria II) and 193 families into Amsterdam criteria I. Results: Of the 142 old S-HNPCC criteria I families 24 fulfilled the Amsterdam criteria II as the data were reclassified according to the revised criteria, increasing the proportion of the families fulfilling the Amsterdam criteria by 12.4%. The mutation detection rate of the revised criteria was very little changed compared to the old criteria; 26% and 27% in the S-HNPCC criteria, and 50% and 52% in the Amsterdam criteria. Conclusion: The mutation detection rate is hardly affected by the revision of the Amsterdam criteria although the population of patients fulfilling the criteria is increased. The value of revised S-HNPCC criteria is equivalent to that of as the old S-HNPCC criteria in selecting of candidate patients for genetic testing.

Familial adenomatous polyposis (FAP): Genotype correlation to FAP phenotype with osteomas and sebaceous cysts

Gardner syndrome is characterized by the triad of colorectal adenomas, soft and hard tissue tumors. This disorder was regarded as a separate disease until the identification of the APC gene when it was recognized that mutations in the APC gene were the underlying cause of both Gardner syndrome and familial adenomatous polyposis (FAP). The present study aimed at examining whether a particular APC genotype could be delineated in FAP patients with benign extracolonic manifestations: sebaceous cysts and/or osteomas. A questionnaire was sent to all Danish FAP patients (N = 234) asking for occurrence of sebaceous cysts and palpable osteomas. Medical records later verified positive findings, when possible. The results for each patient were correlated to the position of his or her mutation in the APC gene. Positive participation compliance was 77% (N = 180), and in 105 of these patients the pathogenic APC mutation was known. Palpable osteomas were reported in 17 of the patients in whom a pathogenic mutation had been identified. Osteomas were only identified in patients with mutations between codon 767 and 1513, a gene area also associated with congenital hypertrophy of the retinal‐pigmented epithelium (CHRPE) and hepatoblastoma. Sebaceous cysts were reported in 51% of the patients, and their APC mutations were evenly distributed in the gene with no particular hotspot. Osteomas appeared most frequently in patients with sebaceous cysts, odds ratio 6.6, P < 0.001. The study provides molecular evidence that Gardner syndrome is a variant of FAP and essentially obsolete in clinical practice.

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

BACKGROUND Observational studies report that higher intake of dietary fibre (a heterogeneous mix including non-starch polysaccharides and resistant starches) is associated with reduced risk of colorectal cancer, but no randomised trials with prevention of colorectal cancer as a primary endpoint have been done. We assessed the effect of resistant starch on the incidence of colorectal cancer. METHODS In the CAPP2 study, individuals with Lynch syndrome were randomly assigned in a two-by-two factorial design to receive 600 mg aspirin or aspirin placebo or 30 g resistant starch or starch placebo, for up to 4 years. Randomisation was done with a block size of 16. Post-intervention, patients entered into double-blind follow-up; participants and investigators were masked to treatment allocation. The primary endpoint for this analysis was development of colorectal cancer in participants randomly assigned to resistant starch or resistant-starch placebo with both intention-to-treat and per-protocol analyses. This study is registered, ISRCTN 59521990. FINDINGS 463 patients were randomly assigned to receive resistant starch and 455 to receive resistant-starch placebo. At a median follow-up 52·7 months (IQR 28·9-78·4), 53 participants developed 61 primary colorectal cancers (27 of 463 participants randomly assigned to resistant starch, 26 of 455 participants assigned to resistant-starch placebo). Intention-to-treat analysis of time to first colorectal cancer showed a hazard ratio (HR) of 1·40 (95% CI 0·78-2·56; p=0·26) and Poisson regression accounting for multiple primary events gave an incidence rate ratio (IRR) of 1·15 (95% CI 0·66-2·00; p=0·61). For those completing 2 years of intervention, per-protocol analysis yielded a HR of 1·09 (0·55-2·19, p=0·80) and an IRR of 0·98 (0·51-1·88, p=0·95). No information on adverse events was gathered during post-intervention follow-up. INTERPRETATION Resistant starch had no detectable effect on cancer development in carriers of hereditary colorectal cancer. Dietary supplementation with resistant starch does not emulate the apparently protective effect of diets rich in dietary fibre against colorectal cancer. 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, and Bayer Pharma.

Surveillance in von Hippel-Lindau disease (vHL).

Poulsen MLM, Budtz‐Jørgensen E, Bisgaard ML. Surveillance in von Hippel‐Lindau disease (vHL).