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H F Vasen

Publications and source records attributed to H F Vasen.

At least 55 records · Page 3Linked to original sources
PubMed1998

Extracolonic manifestations of familial adenomatous polyposis: desmoid tumours, and upper gastrointestinal adenomas and carcinomas.

It is well known that patients with familial adenomatous polyposis (FAP) are at considerable risk of developing extracolonic manifestations of the disease. Particularly, desmoid tumours of the abdominal cavity, and duodenal adenomas and carcinomas are the most serious ones. It is estimated that some 10% of the FAP patients will develop desmoids, whereas 50-90% of the FAP patients will get duodenal adenomas predominantly concentrated on or around the major papilla. Desmoid tumours and duodenal carcinomas are major causes of death in those patients in whom a prophylactic (procto)colectomy has been performed. Desmoids are histologically benign tumours, composed of mature fibroblasts. They usually grow slowly but they can become quite large and may compress or infiltrate surrounding viscera, which might cause significant morbidity as well as mortality. Successful treatment of these tumours is extremely difficult as surgical therapy often requires the removal of considerable lengths of small bowel. Moreover, surgical therapy may lead to uncontrollable bleeding and is seldom radical. Chemotherapy with cytoxic agents seems promising but so far the data are too few for firm conclusions to be drawn. The same holds true for drug regimens which interfere with the metabolic and hormonal metabolism of the tumour. Although various lines of evidence suggest that the adenoma-carcinoma sequence, which is generally accepted for colorectal adenomas, also applies for the duodenal adenomas in FAP patients, it is not clear whether we should screen these patients for upper gastrointestinal adenomas or not. As these polyps are usually small, sessile, multiple and difficult to remove, the benefit of endoscopic surveillance would be the early detection of cancer rather than eradication of the polyps. In addition, evidence that screening and early treatment leads to improvement of the prognosis is not available. Although the role of (procto)colectomy in the treatment of large-bowel polyps is well established in FAP patients, the treatment of their duodenal counterparts is still open for debate. The risk of the development of periampullary cancer is not high enough to warrant an aggressive prophylactic surgical approach, i.e. a Whipple's procedure, immediately after the discovery of duodenal adenomas. The considerable morbidity and mortality rates of this procedure must be weighted against a putative benefit of screening.

Adenoma↗
PubMed1998

Occurrence of thyroid carcinoma in Dutch patients with familial adenomatous polyposis. An epidemiological study and report of new cases.

OBJECTIVES: To assess the occurrence of thyroid cancer in Dutch patients with familial adenomatous polyposis (FAP) and to discuss the value of surveillance. DESIGN: Retrospective analysis of medical records. SETTING: The data were collected from the Dutch FAP registry. PARTICIPANTS: 601 patients with FAP, 339 males and 262 females. RESULTS: The registry contained four female cases with a thyroid carcinoma. The mean age at diagnosis was 30 years (range: 16-46). In two patients it was the presenting symptom of FAP. None of the women died from their thyroid carcinoma during a mean follow-up of 13 years (range: 6-31). The histology revealed one papillary carcinoma, one follicular carcinoma and two mixed papillary/follicular carcinomas. The relative risk (RR) of developing thyroid carcinoma compared with the general Dutch population was 23 (95% confidence interval: 9-61). At the age of 60 years, the cumulative risk (CR) of thyroid carcinoma for female FAP patients was 2.8%. CONCLUSIONS: Young female FAP patients have a significantly increased RR to develop a thyroid carcinoma. It may even be the presenting symptom of FAP. As the CR of thyroid carcinoma is low and the prognosis seems to be good, we recommend only periodical physical examination of the thyroid.

Adenomatous Polyposis Coli↗
PubMed1998

Urinary tract cancer and hereditary nonpolyposis colorectal cancer: risks and screening options.

PURPOSE: We investigate the risk of the different types of urinary tract cancer in hereditary nonpolyposis colorectal cancer families and review screening options. MATERIALS AND METHODS: We retrospectively calculated the relative and cumulative risks of developing urinary tract cancer by comparing tumor occurrence in patients and their first degree relatives in the Dutch hereditary nonpolyposis colorectal cancer registry with those in the general Dutch population. A person-year analysis was used, including data on 1,321 individuals from 50 hereditary nonpolyposis colorectal cancer families. RESULTS: The relative risk of developing transitional cell cancer of the renal pelvis or ureter was 14.04 (95% confidence interval 6.69 to 29.45, p <0.05) and the cumulative risk was 2.6%. The risks of renal (excluding renal pelvis) and bladder cancers were not significantly increased. Urinary tract cancer was diagnosed at a relatively young age and many women were affected. Some familial clustering was observed. CONCLUSIONS: Our findings indicate that hereditary nonpolyposis colorectal cancer is associated with an increased risk of transitional cell cancer of the upper urinary tract. The cumulative risk is relatively low, although a subset of hereditary nonpolyposis colorectal cancer families may be exposed to a much higher risk. As yet nothing is known of the clinical impact of screening for urinary tract cancer in cases of hereditary nonpolyposis colorectal cancer. In a research setting screening by excretory urography of hereditary nonpolyposis colorectal cancer families with a strong history of upper urinary tract cancer should be considered.

Age Factors↗
PubMed1997

Colorectal cancer risk in HNPCC families: development during lifetime and in successive generations. National Collaborative Group on HNPCC.

Members of hereditary non-polyposis colorectal cancer (HNPCC) families develop colorectal cancer at a much higher rate, and at a much younger age, than the general population. To quantify lifetime colorectal cancer risk in HNPCC family members, we calculated the cumulative incidence (CI) in different age categories, and compared this to the general population. Furthermore, we investigated whether successive generations of HNPCC families had earlier onset of disease. In 51 HNPCC families, selected according to the "Amsterdam criteria", the CI of colorectal cancer at age 75 was 40%, compared to only 4% in the general population. The CI ratio (CIR) of HNPCC family members relative to the general population was 148 at age 40, 79 at age 50 and 11 at age 75. Comparing successive generations of HNPCC families, the CI at age 75 increases from 19% in the ancestors to 32% in the first generation and 55% in the second generation. However, Cox proportional hazard analysis showed that this generation effect (RR per generation: 1.8, 95% CL = 1.4-2.2) largely disappears after adjustment for year of birth. In summary, at young ages, HNPCC family members experience an up-to-150 times higher risk for colorectal cancer than the general population. This risk difference declines from age 60 onwards. The earlier age of onset in successive HNPCC generations does not appear to be a biological feature of HNPCC, but reflects a secular time trend in cancer occurrence in these families, similar to that in the general population.

Adult↗
PubMed1997

Meat consumption and preparation, and genetic susceptibility in relation to colorectal adenomas.

Epidemiological evidence suggests that a high meat consumption and/or animal fat intake may increase the risk of colorectal cancer. The objective of this study is to examine the role of dietary factors, in particular meat preparation and consumption, in relation to colorectal adenomas, the pattern of DNA-mutations (e.g. K-ras and p53), and genetic susceptibility (NAT2, HNPCC). In a case control study on diet and colorectal adenomas (sporadic and HNPCC), acetylator status (NAT2) of cases and controls as well as K-ras and p53 mutations in adenomas will be assessed. Consumption and preparation of meat, the primary interest of this study, will be assessed by a food frequency questionnaire designed especially for this purpose.

Adenoma↗
PubMed1997

Molecular analysis of the APC gene in 105 Dutch kindreds with familial adenomatous polyposis: 67 germline mutations identified by DGGE, PTT, and southern analysis.

Germline mutations of the adenomatous polyposis coli (APC) gene are responsible for familial adenomatous polyposis (FAP), an autosomal dominant predisposition to colorectal cancer. We screened the entire coding region of the APC gene for mutations in an unselected series of 105 Dutch FAP kindreds. For the analysis of exons 1-14, we employed the GC-clamped denaturing gradient gel electrophoresis (DGGE), while the large exon 15 was examined using the protein truncation test. Using this approach, we identified 65 pathogenic mutations in the above 105 apparently unrelated FAP families. The mutations were predominantly either frameshifts (39/65) or single base substitutions (18/65), resulting in premature stop codons. Mutations that would predict abnormal RNA splicing were identified in seven cases. In one of the families, a nonconservative amino acid change was found to segregate with the disease. In spite of the large number of APC mutations reported to date, we identified 27 novel germline mutations in our patients, which reiterates the great heterogeneity of the mutation spectrum in FAP. In addition to the point mutations identified in our patients, structural rearrangements of APC were found in two pedigrees, by Southern blot analysis. The present study indicates that the combined use of DGGE, protein truncation test, and Southern blot analysis offers an efficient strategy for the presymptomatic diagnosis of FAP by direct mutation detection. We found that the combined use of the currently available molecular approaches still fails to identify the underlying genetic defect in a significant subset of the FAP families. The possible causes for this limitation are discussed.

Adenomatous Polyposis Coli↗
PubMed1997

Three germline mutations in the TP53 gene.

Three germline mutations in the TP53 tumor-suppressor gene are reported, two of which are not reported previously. A missense mutation at codon 265 of TP53 was found in three patients of a family that complied with the definition of the Li-Fraumeni syndrome. A nonsense mutation in codon 306 was found in a woman who had had a rhabdomyosarcoma at age 4 and a subsequent breast cancer at age 22. She was part of a Li-Fraumeni-like family, but the parental origin of the mutation could not be traced. Finally, while screening for somatic alterations in TP53 in a series of 141 sporadic breast tumors, we detected a constitutional missense mutation in codon 235 in a woman diagnosed with breast cancer at age 26 and a recurrence 4 years later. The recurrence, but not the primary tumor, showed an additional missense mutation at codon 245 as well as loss of the wild-type allele. This suggests that the 245 mutation was particularly important for tumor progression and that there might exist heterogeneity in terms of cancer predisposition potential among the various germline TP53 mutations.

Breast Neoplasms↗
PubMed1997

BRCA1 genomic deletions are major founder mutations in Dutch breast cancer patients.

To date, more than 300 distinct small deletions, insertions and point mutations, mostly leading to premature termination of translation, have been reported in the breast/ovarian-cancer susceptibility gene BRCA1. The elevated frequencies of some mutations in certain ethnic subpopulations are caused by founder effects, rather than by mutation hotspots. Here we report that the currently available mutation spectrum of BRCA1 has been biased by PCR-based mutation-screening methods, such as SSCP, the protein truncation test (PTT) and direct sequencing, using genomic DNA as template. Three large genomic deletions that are not detected by these approaches comprise 36% of all BRCA1 mutations found in Dutch breast-cancer families to date. A 510-bp Alu-mediated deletion comprising exon 22 was found in 8 of 170 breast-cancer families recruited for research purposes and in 6 of 49 probands referred to the Amsterdam Family Cancer Clinic for genetic counselling. In addition, a 3,835-bp Alu-mediated deletion encompassing exon 13 was detected in 4 of 170 research families, while an deletion of approximately 14 kb was detected in a single family [corrected]. Haplotype analyses indicated that each recurrent deletion had a single common ancestor.

BRCA1 Protein↗
PubMed1997

Mutations predisposing to hereditary nonpolyposis colorectal cancer: database and results of a collaborative study. The International Collaborative Group on Hereditary Nonpolyposis Colorectal Cancer.

BACKGROUND & AIMS: Germline mutations in four DNA mismatch repair genes are known to cause susceptibility to hereditary nonpolyposis colorectal cancer (HNPCC). The rapidly increasing information about these mutations needs to be collected and appropriately stored to facilitate further studies on the biological and clinical significance of the findings. METHODS: The International Collaborative Group on HNPCC has established a database of DNA mismatch repair gene mutations and polymorphisms. In this report, 126 predisposing mutations were analyzed. RESULTS: A majority of the mutations affected either the Mut L homologue (MLH) 1 (n = 75) or the Mut S homologue (MSH) 2 (n = 48) and were quite evenly distributed, with some clustering in MSH2 exon 12 and MLH1 exon 16. Most MSH2 mutations consisted of frameshift (60%) or nonsense changes (23%), whereas MLH1 was mainly affected by frameshift (40%) or missense alterations (31%). Although most mutations were unique, a few common recurring mutations were identified. Of the families studied (n = 202), 82% met the Amsterdam criteria and 15% did not; the general mutation profile was similar in both groups. CONCLUSIONS: The construction of mutation profiles will facilitate the development of diagnostic strategies in HNPCC.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Rectal cancer risk in hereditary nonpolyposis colorectal cancer after abdominal colectomy. International Collaborative Group on HNPCC.

OBJECTIVE: The authors analyzed the incidence of rectal cancer in patients with hereditary nonpolyposis colorectal cancer (HNPCC) after an abdominal colectomy. SUMMARY BACKGROUND DATA: The treatment of choice for a newly diagnosed patient with HNPCC with colon cancer is an abdominal colectomy. The incidence of rectal cancer after abdominal colectomy in HNPCC is not known. MATERIALS AND METHODS: A questionnaire was mailed to all International Collaborative Group on HNPCC members to identify patients in whom rectal cancer developed after total, subtotal or completion colectomy. Statistics were performed using the log-rank test, Kaplan-Meier method, and Cox's proportional hazards model. RESULTS: Rectal cancer developed in 8 (11%) of 71 patients a median of 158 months (range, 38-282 months) from their primary procedure. Of these eight patients, adenomas in the rectal mucosa developed in five at risk either before (4) or synchronous (1) with the diagnosis of rectal cancer. At the time of diagnosis of rectal cancer, six of eight patients were being observed. Age at first procedure and whether the patient was under surveillance were the only significant variables (p < 0.05) in the multivariate analysis in terms of rectal cancer risk. The risk of developing rectal cancer was estimated to be 3% every 3 years after abdominal colectomy for the first 12 years. CONCLUSIONS: The risk of rectal cancer in patients with HNPCC after an abdominal colectomy is approximately 12% at 12 years. Age at first surgical procedure and surveillance correlated with rectal cancer risk. Aggressive endoscopic surveillance of the rectum should be performed after abdominal colectomy.

Abdomen↗
PubMed1997

Decision analysis in the management of duodenal adenomatosis in familial adenomatous polyposis.

BACKGROUND: Patients with familial adenomatous polyposis are not only at high risk of developing adenomas in the colorectum but a substantial number of patients also develop polyps in the duodenum. Because treatment of duodenal polyps is extremely difficult and it is unknown how many patients ultimately develop duodenal cancer, the value of surveillance of the upper digestive tract is uncertain. AIMS: (1) To assess the cumulative risk of duodenal cancer in a large series of polyposis patients. (2) To develop a decision model to establish whether surveillance would lead to increased life expectancy. METHODS: Risk analysis was performed in 155 Dutch polyposis families including 601 polyposis patients, and 142 Danish families including 376 patients. Observation time was from birth until date of last contact, death, diagnosis of duodenal cancer, or closing date of the study. RESULTS: Seven Dutch and five Danish patients developed duodenal cancer. The lifetime risk of developing this cancer by the age of 70 was 4% (95% confidence interval 1-7%) in the Dutch series and 3% (95% confidence interval 0-6%) in the Danish series. Decision analysis showed that surveillance led to an increase in life expectancy by seven months. CONCLUSIONS: Surveillance of the upper digestive tract led to a moderate gain in life expectancy. Future studies should evaluate whether this increase in life expectancy outweighs the morbidity of endoscopic examination and proximal pancreaticoduodenectomy.

Adenomatous Polyposis Coli↗
PubMed1996

Molecular genetic tests as a guide to surgical management of familial adenomatous polyposis.

BACKGROUND: In familial adenomatous polyposis the only curative treatment is colectomy, and the choice of operation lies between restorative proctocolectomy (RPC) and colectomy with ileorectal anastomosis (IRA). The RPC procedure carries a higher morbidity but, unlike IRA, removes the risk of subsequent rectal cancer. Since the course of familial adenomatous polyposis is influenced by the site of mutation in the polyposis gene, DNA analysis might be helpful in treatment decisions. METHODS: We evaluated the incidence of rectal cancer in polyposis patients who had undergone IRA, and examined whether the requirement for subsequent rectal excision because of cancer or uncontrollable polyps was related to the site of mutation. FINDINGS: Between 1956 and mid-1995, 225 patients registered at the Netherlands Polyposis Registry had undergone IRA. In 87 of them, a pathogenetic mutation was detected. 72 patients had a mutation located before codon 1250 and 15 patients after this codon. The cumulative risk of rectal cancer 20 years after surgery was 12%, and at that time 42% had undergone rectal excision. The risk of secondary surgery was higher in patients with mutations in the region after codon 1250 than in patients with mutations before this codon (relative risk 2.7, p < 0.05). INTERPRETATION: On this evidence, IRA should be the primary treatment for polyposis in patients with mutations before codon 1250, and RPC in those with mutations after this codon.

Adenomatous Polyposis Coli↗
PubMed1996

The risk of brain tumours in hereditary non-polyposis colorectal cancer (HNPCC).

Hereditary non-polyposis colorectal cancer (HNPCC) is known to be associated with several extracolonic cancers, e.g., cancers of the endometrium, stomach, urinary tract, small bowel and ovary. An association between HNPCC and brain tumours has also been reported, although previous risk analysis did not reveal an excess of this type of tumour. To determine whether HNPCC predisposes patients to brain tumours, we used risk analysis to compare families with HNPCC to those in the general population. Of the 1,321 subjects from 50 HNPCC families (with 60,237 person-years of follow-up) in the Dutch HNPCC Registry which satisfy the Amsterdam Criteria, 312 had colorectal cancer. The registry revealed 14 brain tumours in the HNPCC-patients and their first-degree relatives: 5 astrocytomas, 3 oligodendrogliomas, 1 ependymoma and 5 tumours for which a pathological report was not available. The relative risk of brain tumour in patients with HNPCC and their first-degree relatives was 6 times greater than in the general population (95% confidence interval, 3.5 to 10.1). After exclusion of the cases based only on family history, the relative risk was 4.3 (95% confidence interval, 2.3 to 8.0). Although the relative risk of brain tumour was increased, the lifetime risk was low (3.35%). Because it is not certain whether an improvement of the overall prognosis can be achieved by early diagnosis and intervention, and in view of the low lifetime risk, we do not recommend screening for brain tumours in HNPCC families.

Adolescent↗
PubMed1996

Genetic counseling in a Navajo hereditary nonpolyposis colorectal cancer kindred.

BACKGROUND: Cross-cultural genetic counseling was provided to an extended Navajo Indian family in which the MLH1 gene mutation for hereditary nonpolyposis colorectal cancer (HNPCC) had been identified. The family had been observed by the authors since 1983 and over the years had been provided with intensive education regarding the natural history of HNPCC as well as recommendations for cancer surveillance and management that was responsive to this natural history. METHODS: Following identification of the MLH1 mutation, DNA from family members was evaluated by a reference laboratory (OncorMed, Gaithersburg, MD), where sequences were checked in both the forward and reverse directions against the published sequence for MLH1. The 4bp deletion beginning at the first nucleotide of codon 727 was easily visualized in the heterozygous condition in both affected and predispositional individuals. The family was reeducated as a group and then provided further education individually during genetic counseling sessions, at which time they were appraised of potential penalties, such as insurance and employer discrimination, and psychological sequelae that could result from knowledge of the MLH1 mutation. Strict confidentiality of this information was assured. RESULTS: DNA testing was performed on 51 family members. Twenty-three individuals were counseled, seven of whom were positive for MHL1. Reactions ranged from full acceptance of the genetic implications to traditional Navajo reasoning such as the family had been cursed. CONCLUSIONS: DNA-based genetic counseling requires comparison and empathy, coupled with intensive preeducation regarding potential penalties and advantages that might emanate from this knowledge. Special care must be given to patients' culture, beliefs, and traditions.

Adult↗
PubMed1996

Germline mutations in the 3' part of APC exon 15 do not result in truncated proteins and are associated with attenuated adenomatous polyposis coli.

Familial adenomatous polyposis (FAP) is an inherited predisposition to colorectal cancer characterized by the development of numerous adenomatous polyps predominantly in the colorectal region. Germline mutations in the adenomatous polyposis coli (APC) gene are responsible for most cases of FAP. Mutations at the 5' end of APC are known to be associated with a relatively mild form of the disease, called attenuated adenomatous polyposis coli (AAPC). We identified a frameshift mutation in the 3' part of exon 15, resulting in a stop codon at 1862, in a large Dutch kindred with AAPC. Western blot analysis of lymphoblastoid cell lines derived from affected family members from this kindred, as well as from a previously reported Swiss family carrying a frameshift mutation at codon 1987 and displaying a similar attenuated phenotype, showed only the wild-type APC protein. Our study indicates that chain-terminating mutations located in the 3' part of APC do not result in detectable truncated polypeptides and we hypothesize that this is likely to be the basis for the observed AAPC phenotype.

Adenomatous Polyposis Coli↗