Collective effective dose in Europe from X-ray and nuclear medicine procedures

Population doses from radiodiagnostic (X-ray and nuclear medicine) procedures in Europe were estimated based on data collected from 36 European countries. For X-ray procedures in EU and EFTA countries (except Liechtenstein) the collective effective dose is 547,500 man Sv, resulting in a mean effective dose of 1.06 mSv per caput. For all European countries included in the survey the collective effective dose is 605,000 man Sv, resulting in a mean effective dose of 1.05 mSv per caput. For nuclear medicine procedures in EU countries and EFTA (except Liechtenstein) countries the collective effective dose is 30,700 man Sv, resulting in a mean effective dose of 0.06 mSv per caput. For all European countries included in the survey the collective effective dose is 31,100 man Sv, resulting in a mean effective dose of 0.05 mSv per caput.

Indication-based national diagnostic reference levels for paediatric CT: a new approach with proposed values

Indication-based national diagnostic reference levels (DRLs) for a few most common paediatric computed tomography (CT) examinations are proposed. Patient dose data (CTDI vol and dose length product) were collected for over 1000 patients in 4 university hospitals with best experiences in paediatric CT. Four indications for chest CT and two for abdomen (abdomen + pelvis), chest + abdomen and head CT were considered. The DRLs for the body examinations are proposed as exponential DRL-curves, where CTDI vol and dose length product are presented as a function of patient weight. The same DRL curve applies to all the indications studied. The basic 75 % level curve is supplemented by 50 % level curve to enable considerations on varying levels of technology. For head CT, DRLs are proposed for a few age groups (1, 1-5, 5-10 and 10-15 y), separately for routine CT and CT for ventricular size. The proposed DRLs are generally lower than the few published DRLs in other countries.

Analysis of factors correlating with medical radiological examination frequencies

The European Commission (EC) funded project Dose Datamed 2 (DDM2) had two objectives: to collect available data on patient doses from the radiodiagnostic procedures (X-ray and nuclear medicine) in Europe, and to facilitate the implementation of the Radiation Protection 154 Guidelines (RP154). Besides the collection of frequency and dose data, two questionnaires were issued to gather information about medical radiological imaging. This article analyses a possible correlation between the collected frequency data, selected variables from the results of the detailed questionnaire and national economic data. Based on a 35 countries dataset, there is no correlation between the gross domestic product (GDP) and the total number of X-ray examinations in a country. However, there is a significant correlation (p < 0.01) between the GDP and the overall CT examination frequency. High income countries perform more CT examinations per inhabitant. That suggests that planar X-ray examinations are replaced by CT examinations.

Effectiveness of screening for colorectal cancer with a faecal occult-blood test, in Finland

Background

Screening for colorectal cancer (CRC) with guaiac-based faecal occult-blood test (FOBT) has been reported to reduce CRC mortality in randomised trials in the 1990s, but not in routine screening, so far. In Finland, a large randomised study on biennial FOB screening for CRC was gradually nested as part of the routine health services from 2004. We evaluate the effectiveness of screening as a public health policy in the largest population so far reported.

Methods

We randomly allocated (1:1) men and women aged 60–69 years to those invited for screening and those not invited (controls), between 2004 and 2012. This resulted in 180 210 subjects in the screening arm and 180 282 in the control arm. In 2012, the programme covered 43% of the target age population in Finland.

Results

The median follow-up time was 4.5 years (maximum 8.3 years), with a total of 1.6 million person-years. The CRC incidence rate ratio between the screening and control arm was 1.11 (95% CI 1.01 to 1.23). The mortality rate ratio from CRC between the screening and control arm was 1.04 (0.84 to 1.28), respectively. The CRC mortality risk ratio was 0.88 (0.66 to 1.16) and 1.33 (0.94 to 1.87) in males and females, respectively.

Conclusions

We did not find any effect in a randomised health services study of FOBT screening on CRC mortality. The substantial effect difference between males and females is inconsistent with the evidence from randomised clinical trials and with the recommendations of several international organisations. Even if our findings are still inconclusive, they highlight the importance of randomised evaluation when new health policies are implemented.

Trial registration

002_2010_august.

Identification of 33 candidate oncogenes by screening for base-specific mutations

Background:

Genes with recurrent codon-specific somatic mutations are likely drivers of tumorigenesis and potential therapeutic targets. Hypermutable cancers may represent a sensitive system for generation and selection of oncogenic mutations.

Methods:

We utilised exome-sequencing data on 25 sporadic microsatellite-instable (MSI) colorectal cancers (CRCs) and searched for base-specific somatic mutation hotspots.

Results:

We identified novel mutation hotspots in 33 genes. Fourteen genes displayed mutations in the validation set of 254 MSI CRCs: ANTXR1, MORC2, CEP135, CRYBB1, GALNT9, KRT82, PI15, SLC36A1, CNTF, GLDC, MBTPS1, OR9Q2, R3HDM1 and TTPAL. A database search found examples of the hotspot mutations in multiple cancer types.

Conclusions:

This work reveals a variety of new recurrent candidate oncogene mutations to be further scrutinised as potential therapeutic targets.

Health-related quality of life in colorectal cancer

AIM

As a consequence of the improved survival of patients and of cost-effectiveness requirements for new treatments, health-related quality of life (HRQoL) issues have gained increasing attention in colorectal cancer (CRC). This cross-sectional study assesses HRQoL in several health states of CRC and explores factors influencing HRQoL.

METHOD

Five hundred and eight Finnish CRC patients (aged 26-96 years; colon cancer 56%; women 47%) assessed their HRQoL using generic 15D and EQ-5D and cancer-specific EORTC QLQ-C30 questionnaires. Patients were divided into five groups: primary treatment, rehabilitation, remission, metastatic disease and palliative care. The patients' HRQoL was compared with population reference values. Multivariate modelling was used to find factors associated with HRQoL scores.

RESULTS

The HRQoL of CRC patients is fairly good and comparable with that of the standardized general population except for those under palliative care. The mean 15D score of patients in the primary treatment group was 0.889 (95% CI 0.869-0.914), in rehabilitation 0.877 (0.855-0.907), in remission 0.886 (0.875-0.903), in metastatic disease 0.860 (0.844-0.878) and in palliative care 0.758 (0.716-0.808). The respective EQ-5D scores were 0.760 (0.699-0.823), 0.835 (0.777-0.881), 0.850 (0.828-0.882), 0.820 (0.783-0.858) and 0.643 (0.546-0.747). Multivariate analysis showed that fatigue, pain, age and financial difficulties had a marked negative impact on HRQoL.

CONCLUSION

The mean HRQoL scores of CRC patients varied considerably depending on the HRQoL instrument used, but remained surprisingly good up to the palliative stage. In addition to age- and cancer-related symptoms, financial difficulties also had a clear negative impact on HRQoL, which needs to be taken into consideration when supporting patient HRQoL.

Radiation dose estimation in computed tomography examinations using NRPB-SR250 software in aretrospective analysis of a patient population

Computed tomography (CT) imaging contributes to a major part of medical radiation exposure. With regard to patients safety, frequent CT examinations (CTEs) performed on the same patient are of particular concern. Tools for tracking the individual patient radiation exposure history and cumulative dose assessment may become important. Here, the applicability of the NRPB-SR250 software was assessed in a retrospective analysis of radiation doses from CTE made consecutively in male patients. Most of the examinations focused on the abdomen or the whole body. The mean number of CTs per patient was 6.8. Significant cumulative effective doses were observed: 76 (66 %) patients received an effective dose higher than 50 mSv, while the maximum was ∼280 mSv. A more than 3-fold effective dose difference was observed between scanners, depending on the scanning protocols. The NRPB-SR250 software proved to be a robust tool for the assessment of organ doses and the effective radiation dose from CT, while challenges were encountered in finding the precise imaging data in retrospective protocols.

Duodenal surveillance improves the prognosis after duodenal cancer in familial adenomatous polyposis

AIM

Duodenal adenomatosis in familial adenomatous polyposis results in a cancer risk that increases with age. Endoscopic surveillance has been recommended, but the effect has not yet been documented. The aim of this study was to present the results of long-term duodenal surveillance and to evaluate the risk of cancer development.

METHOD

Follow up of patients in a previous study with gastroduodenoscopy in 1990-2010. Statistical analysis included the χ(2) test, actuarial method and Kaplan-Meier analysis.

RESULTS

Among 304 patients, 261 (86%) had more than one endoscopy. The median follow up was 14 (interquartile range, 9-17) years. The cumulative lifetime risk of duodenal adenomatosis was 88% (95% CI, 84-93), and of Spigelman stage IV was 35% (95% CI, 25-45). The Spigelman stage improved in 32 (12%) patients, remained unchanged in 88 (34%) and worsened in 116 (44%). Twenty (7%) patients had duodenal cancer at a median age of 56 (range, 44-82) years. The cumulative cancer incidence was 18% at 75 years of age (95% CI, 8-28) and increased with increasing Spigelman stage at the index endoscopy to 33% in Spigelman stage IV (P < 0.0001). The median overall survival was 6.4 years (95% CI, 1.7 to not estimated): 8 years after a screen-detected cancer vs 0.8 years (95% CI, 0.03-1.7) after a symptomatic cancer (P < 0.0001). The location of the mutation in the APC gene did not influence the risk of developing Spigelman stage IV (P = 0.46) or duodenal cancer (P = 0.83).

CONCLUSION

The risk of duodenal cancer in familial adenomatous polyposis is considerable, and regular surveillance and cancer prophylactic surgery result in a significantly improved prognosis.

Justification of diagnostic medical exposures: some practical issues. Report of an International Atomic Energy Agency Consultation

OBJECTIVES

The Radiation Protection of Patients Unit of the International Atomic Energy Agency (IAEA) is concerned about the effectiveness of justification of diagnostic medical exposures. Recent published work and the report of an initial IAEA consultation in the area gave grounds for such concerns. There is a significant level of inappropriate usage, and, in some cases, a poor level of awareness of dose and risk among some key groups involved. This article aims to address this.

METHODS

The IAEA convened a second group of experts in November 2008 to review practical and achievable actions that might lead to more effective justification.

RESULTS

This report summarises the matters that this group considered and the outcome of their deliberations. There is a need for improved communication, both within professions and between professionals on one hand, and between professionals and the patients/public on the other. Coupled with this, the issue of consent to imaging procedures was revisited. The need for good evidence-based referral guidelines or criteria of acceptability was emphasised, as was the need for their global adaptation and dissemination.

CONCLUSION

Clinical audit was regarded as a key tool in ensuring that justification becomes an effective, transparent and accountable part of normal radiological practice. In summary, justification would be facilitated by the "3 As": awareness, appropriateness and audit.

Patient doses in paediatric CT: feasibility of setting diagnostic reference levels

Despite the fact that doses to paediatric patients from computed tomography (CT) examinations are of special concern, only few data or studies for setting of paediatric diagnostic reference levels (DRLs) have been published. In this study, doses to children were estimated from chest and head CT, in order to study the feasibility of DRLs for these examinations. It is shown that for the DRLs, patient dose data from different CT scanners should be collected in age or weight groups, possibly for different indications. For practical reasons, the DRLs for paediatric chest CT should be given as a continuous DRL curve as a function of patient weight. For paediatric head CT, DRLs for a few age groups could be given. The users of the DRLs should be aware of the calibration phantom applied in the console calibration for different paediatric scanning protocols. The feasibility of DRLs should be re-evaluated every 2-3 y.

Clinical audit: Development of the criteria of good practices

Clinical audit is a systematic review of the procedures in order to improve the quality and the outcome of patient care, whereby the procedures are examined against agreed standards for good medical RADIOLOGICAL procedures. The criteria of good procedures (i.e. the good practice) are thus the cornerstones for development of clinical audits: these should be the basis of assessments regardless of the type of the audit--external, internal, comprehensive or partial. A lot of criteria for good practices are available through the recommendations and publications by international and national professional societies and other relevant organisations. For practical use in clinical audits, the criteria need to be compiled, sorted out and agreed on for the particular aims of an audit (comprehensive or partial, external or internal). The national professional and scientific societies can provide valuable contribution to this development. For examination--or treatment-specific criteria--preliminary consensus needs to be obtained with the help of clinical experts, while clinical audits can be useful as a benchmarking tool to improve the criteria.

Estimated collective effective dose to the population from X-ray and nuclear medicine examinations in Finland

The collective effective doses to the population from X-ray and nuclear medicine (NM) examinations in Finland in 2008 and 2009, respectively, were estimated. The estimated collective effective dose per inhabitant was 0.45 mSv from X-ray examinations and 0.03 mSv from NM examinations. The collective effective doses per inhabitant have not changed substantially during the last 10 y. However, proportional dose due to CT examinations has increased from 50 % in 2005 to 58 % in 2009 of the total collective effective dose from all X-ray examinations and proportional dose of PET examinations from 7 to 13 % of the total collective effective dose from NM examinations. The collective effective dose from conventional plain radiography was over 20 % higher when estimated using the new (ICRP 103) tissue weighting factors than that obtained using the old (ICRP 60) tissue weighting factors.

Early detection of colorectal cancer with faecal occult blood test screening

BACKGROUND

Faecal occult blood test (FOBT) screening has been shown to decrease the incidence and mortality from colorectal cancer. This study compared the stage profile of patients with colorectal cancer diagnosed at the first FOBT screening round with that of an unscreened control group.

METHODS

Subjects aged 60-64 years were allocated randomly to biennial FOBT screening (52 998 subjects) or a control group (53 002) in a Finnish prospective public health policy in 2004-2006. FOBT was performed with a guaiac test. At the end of 2007 the screened and control populations were linked to the Finnish Cancer Registry database, and the colonoscopic findings in the screen positives were analysed.

RESULTS

Early-stage colorectal cancer was observed in 52 per cent of the FOBT-positive subjects, in 42.2 per cent of the total screened population and in 38 per cent of the control population (P = 0.191 for FOBT positives, P = 0.592 for total screened population). The prevalence of adenomas and colorectal cancer was 31.5 and 8.2 per cent respectively among the 806 subjects with a positive FOBT. Some 27.3 per cent of all colorectal tumours in the screened population were interval cancers. The tumour was located in the right colon in 28.9 per cent of the screened subjects and 22 per cent of controls (P = 0.255).

CONCLUSION

Biennial FOBT screening improves detection of colorectal cancer at the first screening round, but the high percentage of interval cancers is a cause for concern.

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.

A clinical audit programme for diagnostic radiology: the approach adopted by the International Atomic Energy Agency

The International Atomic Energy Agency (IAEA) has a mandate to assist member states in areas of human health and particularly in the use of radiation for diagnosis and treatment. Clinical audit is seen as an essential tool to assist in assuring the quality of radiation medicine, particularly in the instance of multidisciplinary audit of diagnostic radiology. Consequently, an external clinical audit programme has been developed by the IAEA to examine the structure and processes existent at a clinical site, with the basic objectives of: (1) improvement in the quality of patient care; (2) promotion of the effective use of resources; (3) enhancement of the provision and organisation of clinical services; (4) further professional education and training. These objectives apply in four general areas of service delivery, namely quality management and infrastructure, patient procedures, technical procedures and education, training and research. In the IAEA approach, the audit process is initiated by a request from the centre seeking the audit. A three-member team, comprising a radiologist, medical physicist and radiographer, subsequently undertakes a 5-d audit visit to the clinical site to perform the audit and write the formal audit report. Preparation for the audit visit is crucial and involves the local clinical centre completing a form, which provides the audit team with information on the clinical centre. While all main aspects of clinical structure and process are examined, particular attention is paid to radiation-related activities as described in the relevant documents such as the IAEA Basic Safety Standards, the Code of Practice for Dosimetry in Diagnostic Radiology and related equipment and quality assurance documentation. It should be stressed, however, that the clinical audit does not have any regulatory function. The main purpose of the IAEA approach to clinical audit is one of promoting quality improvement and learning. This paper describes the background to the clinical audit programme and the IAEA clinical audit protocol.

Comparison of double dosimetry algorithms for estimating the effective dose in occupational dosimetry of interventional radiology staff

'Double dosimetry' i.e. measurement with two dosemeters, one located above the protective apron and one under has been recommended in interventional radiology (IR) to determine the effective dose to staff. Several algorithms have been developed to calculate the effective dose from the readings of the two dosemeters, but there is no international consensus on what is the best algorithm. In this work, a few of the most recently developed algorithms have been tested in typical IR conditions. The effective dose and personnel dosemeter readings were obtained experimentally by using thermoluminescent dosemeters in and on a Rando-Alderson phantom provided with a lead apron. In addition, the effective dose and personnel dosemeter readings were calculated by the Monte Carlo method for the same irradiation geometry. The results suggest that most of the algorithms overestimate effective dose in the selected IR conditions, but there is also a risk of underestimation by using the least conservative algorithms. Two of the algorithms seem to comply best with the chosen criteria of performance, i.e. no underestimation, minimum overestimation and close estimation of effective dose in typical IR conditions. However, it might not be justified to generalise the results. It is recommended that whenever personnel doses approach or exceed the dose limit, IR conditions should be further investigated and the possibility of over- or under-estimation of effective dose by the algorithm used should be considered.

Overview of double dosimetry procedures for the determination of the effective dose to the interventional radiology staff

In interventional radiology, for an accurate determination of effective dose to the staff, measurements with two dosemeters have been recommended, one located above and one under the protective apron. Such 'double dosimetry' practices and the algorithms used for the determination of effective dose were reviewed in this study by circulating a questionnaire and by an extensive literature search. The results indicated that regulations for double dosimetry almost do not exist and there is no firm consensus on the most suitable calculation algorithms. The calculation of effective dose is mainly based on the single dosemeter measurements, in which either personal dose equivalent, directly, (dosemeter below the apron) or a fraction of personal dose equivalent (dosemeter above the apron) is taken as an assessment of effective dose. The most recent studies suggest that there might not be just one double dosimetry algorithm that would be optimum for all interventional radiology procedures. Further investigations in several critical configurations of interventional radiology procedures are needed to assess the suitability of the proposed algorithms.

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

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.

Results of a European survey on patient doses in paediatric radiology

Paediatric patients represent a very specific group within the radiology department. Compared to adult patients, they are more sensitive to radiation. As they are sometimes submitted to several radiology procedures, dose and image quality should be well balanced. Nowadays, only a few centres specialize in paediatric imaging, and knowledge of paediatric patient doses is, therefore, very scattered. The effect of the introduction of digital technology on paediatric patient doses remains largely undocumented. Data collected in the present survey illustrate that there is a clear need for standardisation in this domain. The proposal of a European diagnostic reference level (DRL) is quite difficult. Preliminary DRLs, based on typically 5-7 radiology centres per examination are proposed. The 'effective dose' may or may not be a very rigorous parameter, but it still remains useful nowadays to calculate a parameter that summarises the possible radiation-induced detriment to these young patients. However, conversion factors for calculation of the effective dose should be harmonised. Future studies should include an image quality evaluation study, using criteria that account for digital equipment. Data collection would be straightforward and could be performed in a systematic and automatic way if DICOM headers of digital images would include appropriate as well as relevant information for the particular case of paediatric examinations.

Patient dose in interventional radiology: a European survey

Patient doses for a few common fluoroscopy-guided procedures in interventional radiology (IR) (excluding cardiology) were collected from a few radiological departments in 13 European countries. The major aim was to evaluate patient doses for the basis of the reference levels. In total, data for 20 procedures for about 1300 patients were collected. There were many-fold variations in the number of IR equipment and procedures per population, in the entrance dose rates, and in the patient dose data (total dose area product or DAP, fluoroscopy time and number of frames). There was no clear correlation between the total DAP and entrance dose rate, or between the total DAP and fluoroscopy time, indicating that a number of parameters affect the differences. Because of the limited number of patients, preliminary reference levels were proposed only for a few procedures. There is a need to improve the optimisation of IR procedures and their definitions and grouping, in order to account for their different complexities.

Diagnostic reference levels for thorax X-ray examinations of paediatric patients

Based on the Medical Exposure Directive of the European Commission, 97/43/Euratom, The Radiation and Nuclear Safety Authority (STUK) in Finland has the responsibility for setting national diagnostic reference levels (DRLs) for the most common radiological examinations. Paediatric patients deserve special attention because of the higher radiation risk compared with adults. The purpose of this paper is to present a method that takes into account patient size when setting DRLs in paediatric patients. The overall data consisted of patient doses collected from six hospitals during the years 1994-2001, and new measurements in two hospitals in 2004. In total, there were 700 chest examinations. The method established by the National Radiological Protection Board (UK) for setting DRLs was not considered feasible in Finnish practice. Patient doses correlated exponentially with the projection thickness, which was measured directly for each patient. Since 1 January 2006, paediatric DRLs for conventional chest examinations have been specified in Finland as a DRL curve by using both dose quantities (entrance surface doses (ESD) and dose-area product (DAP)) as a function of patient projection thickness.

No evidence for dual role of loss of heterozygosity in hereditary non-polyposis colorectal cancer

Hereditary non-polyposis colorectal cancer (HNPCC) is caused by germline mutations in mismatch repair (MMR) genes, mostly MLH1 and MSH2. Somatic inactivation of the wild-type allele of the respective MMR gene is required for tumor development. Unexpectedly, a recent study utilizing DNA from paraffin-embedded tissue material detected frequent loss of the mutant MMR gene allele in HNPCC tumors. Dual role for loss of heterozygosity (LOH) was proposed. If somatic loss of the wild-type MMR gene allele had occurred through point mutation or promoter hypermethylation, frequent somatic deletions at the region of the MMR gene locus, perhaps targeting other relevant cancer genes, could quite commonly lead to loss of the mutant allele. To test this hypothesis, we studied a population-based series of 25 fresh-frozen HNPCC tumors with a germline mutation in MLH1 or MSH2 for LOH. Fourteen of the 25 tumors (56%) showed LOH at the respective locus, and all 14 losses targeted the wild-type allele (P=0.00006). These results strongly support the traditional two-hit model of HNPCC gene inactivation.

LKB1 exonic and whole gene deletions are a common cause of Peutz-Jeghers syndrome

BACKGROUND

LKB1/STK11 germline mutations cause Peutz-Jeghers syndrome (PJS). The existence of a second PJS locus is controversial, the evidence in its favour being families unlinked to LKB1 and the low frequency of LKB1 mutations found using conventional methods in several studies. Exonic and whole gene deletion or duplication events cannot be detected by routine mutation screening methods.

OBJECTIVE

To seek evidence for LKB1 germline deletions or duplications by screening patients meeting clinical criteria for PJS but without detected mutations on conventional screening.

METHODS

From an original cohort of 76 patients, 48 were found to have a germline mutation by direct sequencing; the remaining 28 were examined using multiplex ligation dependent probe amplification (MLPA) analysis to detect LKB1 copy number changes.

RESULTS

Deletions were found in 11 of the 28 patients (39%)--that is, 14% of all PJS patients (11/76). Five patients had whole gene deletions, two had the promoter and exon 1 deleted, and in one patient exon 8 was deleted. Other deletions events involved: loss of exons 2-10; deletion of the promoter and exons 1-3; and loss of part of the promoter. No duplications were detected. Nine samples with deletions were sequenced at reported single nucleotide polymorphisms to exclude heterozygosity; homozygosity was found in all cases. No MLPA copy number changes were detected in 22 healthy individuals.

CONCLUSIONS

These results lessen the possibility of a second PJS locus, as the detection rate of germline mutations in PJS patients was about 80% (59/76). It is suggested that MLPA, or a suitable alternative, should be used for routine genetic testing of PJS patients in clinical practice.

Serrated carcinomas form a subclass of colorectal cancer with distinct molecular basis

Serrated colorectal carcinomas (CRCs) are morphologically different from conventional CRCs and have been proposed to follow a distinct pathway of CRC formation. Despite studies of single molecular events in this tumor type, the diagnosis of serrated CRC relies on morphology and the putative unique biological character of these tumors has not been established. Here we show that the gene expression profiling of 37 CRCs separated serrated and conventional CRCs into two distinct branches in unsupervised hierarchical clustering (P-value 7.8 x 10(-7)), and revealed 201 differentially expressed genes representing potential biomarkers for serrated CRC. Immunohistochemistry was utilized to verify the key findings in the 37 CRCs examined by expression profiling, and a separate validation set of 37 serrated and 86 conventional CRCs was examined to evaluate the candidate biomarkers in an extended sample material. Ephrin receptor B2, hypoxia-inducible factor 1-alpha and patched appeared as proteins important for genesis of serrated CRC. This study establishes serrated CRCs as a biologically distinct subclass of CRC and represents a step forward in the molecular classification of these cancers. The study also provides a platform to understand the molecular basis of serrated CRC and in long term may contribute to the development of specific treatment options for this tumor type.

Gene expression signatures for colorectal cancer microsatellite status and HNPCC

The majority of microsatellite instable (MSI) colorectal cancers are sporadic, but a subset belongs to the syndrome hereditary nonpolyposis colorectal cancer (HNPCC). Microsatellite instability is caused by dysfunction of the mismatch repair (MMR) system that leads to a mutator phenotype, and MSI is correlated to prognosis and response to chemotherapy. Gene expression signatures as predictive markers are being developed for many cancers, and the identification of a signature for MMR deficiency would be of interest both clinically and biologically. To address this issue, we profiled the gene expression of 101 stage II and III colorectal cancers (34 MSI, 67 microsatellite stable (MSS)) using high-density oligonucleotide microarrays. From these data, we constructed a nine-gene signature capable of separating the mismatch repair proficient and deficient tumours. Subsequently, we demonstrated the robustness of the signature by transferring it to a real-time RT-PCR platform. Using this platform, the signature was validated on an independent test set consisting of 47 tumours (10 MSI, 37 MSS), of which 45 were correctly classified. In a second step, we constructed a signature capable of separating MMR-deficient tumours into sporadic MSI and HNPCC cases, and validated this by a mathematical cross-validation approach. The demonstration that this two-step classification approach can identify MSI as well as HNPCC cases merits further gene expression studies to identify prognostic signatures.

The C/C-13910 genotype of adult-type hypolactasia is associated with an increased risk of colorectal cancer in the Finnish population

BACKGROUND AND AIMS

The role of nutrition in the pathogenesis of colorectal cancer is not fully understood. Milk products are an essential part of human nutrition in Western countries. Absorption of lactose, the main sugar of milk, is regulated by the activity of the lactase enzyme in the gut wall. The activity of lactase is genetically determined and is associated with a C/T single nucleotide polymorphism residing 13910 bp upstream of the lactase coding sequence. Here we have studied the relationship between the C/T(-13910) polymorphism and colorectal cancer in Finnish, British, and Spanish populations.

PATIENTS AND METHODS

A total of 2766 subjects, including 963 Finnish, 283 British, and 163 Spanish subjects with colorectal cancer, and 773 Finnish, 363 British, and 221 Spanish control subjects, were genotyped for the C/T(-13910) variant by polymerase chain reaction minisequencing.

RESULTS

The C/C(-13910) genotype, which is a robust molecular marker of low lactase activity (lactase non-persistence), was found to significantly associate with the risk of colorectal cancer (p = 0.015) in the Finnish subjects, with an odds ratio of 1.40 (95% confidence interval 1.07-1.85). No association was found with site, histology, or stage of the tumour. No significant risk was detected in the British or Spanish populations.

CONCLUSION

Low lactase enzyme activity, defined by genotyping of the C/T(-13910) variant, may increase the risk of colorectal cancer. Further studies are warranted to investigate the role of milk and other dairy products in the pathogenesis of colon cancer in different populations.

Factors associated with disease activity of pouchitis after surgery for ulcerative colitis

BACKGROUND

Pouchitis occurs in 20% to 59% of patients operated on for ulcerative colitis. Several risk factors have been identified for the development of pouchitis. This study was undertaken to assess the incidence of pouchitis at least 5 years after ileal pouch-anal anastomosis for ulcerative colitis, and to evaluate possible predictive factors for inflammation activity.

METHODS

A total of 107 subjects were enrolled (54 M, 53 F, mean age 45 years, range 23-69) with a J-pouch created between 1985 and 1994. Preoperative medical history was determined, an endoscopy performed, and biopsies taken from the pouch and neoterminal ileum above the pouch. Sera from all patients were tested for perinuclear antineutrophil cytoplasmic antibodies (pANCAs).

RESULTS

After a mean 7.5-years' follow-up time, the cumulative incidence of pouchitis was 58%. Risk for development of active inflammation (PDAI > or = 7) was significantly higher in patients with preoperative extraintestinal manifestations (OR 2.7, 95% CI 1.1-6.4, P=0.03). Patients who had had ankylosing spondylitis (AS) (OR 11.7, P=0.006) or iritis (OR 9.8, P=0.013) were especially at risk. Positive titres of pANCAs were associated with inflammation in the neoterminal ileum; 80% of patients with high pANCA levels (>100) had pouchitis. Current smokers tended to have a more benign disease course.

CONCLUSIONS

A correlation existed between the prevalence and titre of pANCAs and extent and disease activity of pouchitis. Chronic pouchitis may continuously stimulate the immunological process, keeping pANCAs at detectable levels. A strong correlation between AS, iritis and pouchitis suggests a common link in their pathogenesis.

Duodenal adenomatosis in familial adenomatous polyposis

BACKGROUND

The prevalence of duodenal carcinoma is much higher in familial adenomatous polyposis (FAP) than in the background population, and duodenal adenomatosis is found in most polyposis patients.

AIMS

To describe the long term natural history of duodenal adenomatosis in FAP and evaluate if cancer prophylactic surveillance of the duodenum is indicated.

METHODS

A prospective five nation study was carried out in the Nordic countries and the Netherlands.

PATIENTS

A total of 368 patients were examined by gastroduodenoscopy at two year intervals during the period 1990-2001.

RESULTS

At the first endoscopy, 238 (65%) patients had duodenal adenomas at a median age of 38 years. Median follow up was 7.6 years. The cumulative incidence of adenomatosis at age 70 years was 90% (95% confidence interval (CI) 79-100%), and of Spigelman stage IV 52% (95% CI 28-76%). The probability of an advanced Spigelman score increased during the study period (p<0.0001) due to an increasing number and size of adenomas. Two patients had asymptomatic duodenal carcinoma at their first endoscopy while four developed carcinoma during the study at a median age of 52 years (range 26-58). The cumulative incidence rate of cancer was 4.5% at age 57 years (95% CI 0.1-8.9%) and the risk was higher in patients with Spigelman stage IV at their first endoscopy than in those with stages 0-III (p<0.01).

CONCLUSIONS

The natural course of duodenal adenomatosis has now been described in detail. The high incidence and increasing severity of duodenal adenomatosis with age justifies prophylactic examination, and a programme is presented for upper gastrointestinal endoscopic surveillance.

Frequent loss of SMAD4/DPC4 protein in colorectal cancers

BACKGROUND AND AIMS

Loss of DNA sequences from chromosome 18q21 is a major genetic change in colorectal tumorigenesis. Multiple genes have been identified in this area. One of these, DPC4 (deleted in pancreatic cancer 4, also known as SMAD4), is mutated in a minor subset of colorectal carcinomas as well as in germlines of humans predisposed to colon tumours.

PATIENTS AND METHODS

The involvement of SMAD4 in sporadic colorectal neoplasia was evaluated by immunohistochemistry in 53 unselected cases and 27 cases displaying microsatellite instability.

RESULTS

SMAD4 expression was absent in 20 of 53 (38%) unselected colorectal carcinomas, and reduced in another 15 (28%) cases. However, 26 of 27 cancers displaying microsatellite instability and TGF-betaIIR mutations were positive for SMAD4 immunostaining.

CONCLUSIONS

Loss of SMAD4 expression may play a more prominent role in colon cancer than anticipated based on genetic evidence, but not in mutator phenotype tumours.

Familial and sporadic inflammatory bowel disease: comparison of clinical features and serological markers in a genetically homogeneous population

BACKGROUND

The familial occurrence of inflammatory bowel disease (IBD) and the clinical features of familial and sporadic IBD in the genetically homogeneous Finnish population are evaluated.

METHODS

257 patients with Crohn disease (CD) and 436 with ulcerative colitis (UC) participated in the study. They were asked whether IBD was present (familial IBD) or absent (sporadic IBD) in their first-degree relatives. Data on the clinical course of the disease were collected from the patient records. Antibodies to Saccharomyces cerevisiae (ASCA) and anti-neutrophil cytoplasmic antibodies (ANCA) were determined from serum samples.

RESULTS

Affected first-degree relatives were found in 15.6% of patients with CD and in 13.8% of patients with UC. In familial cases CD was more often located in the ileum (38% versus 21%) and less often in the ileocolon (35% versus 50%) (P< 0.05) than in sporadic cases. A greater percentage of CD patients than UC patients were smokers (47% versus 13%; P < 0.01). An elevated level of IgA and/or IgG antibodies for ASCA was found more often in CD patients than in UC patients (59% versus 14%; P < 0.01), while pANCA were found more often in UC than in CD patients (48% versus 12%; P < 0.01). The combination of pANCA-ASCA+ yielded a sensitivity, specificity and positive predictive value of 48%, 92% and 90%, respectively, for CD, and the combination of pANCA + ASCA- of 55%, 94% and 90%, respectively, for UC.

CONCLUSIONS

The percentage of familial IBD cases in Finland is comparable to that reported elsewhere in Europe. No important clinical differences between patients with familial and sporadic forms of the disease were found. ASCA is associated with both familial and sporadic CD and pANCA with UC, but low sensitivity diminishes their value as a serological marker of IBD or as a differential diagnostic test between CD and UC.

Genetic and clinical characterisation of familial adenomatous polyposis: a population based study

BACKGROUND

Familial adenomatous polyposis (FAP) is a rare autosomal dominantly inherited disease predisposing to colon cancer and caused by germline mutations in the APC (adenomatous polyposis coli) gene.

AIMS

We conducted a population based study to evaluate the prevalence and clinical implications of APC mutations among Finnish FAP kindreds. A possible founder effect in parallel with previous observations in hereditary non-polyposis colon cancer (HNPCC) was addressed.

PATIENTS

Affected individuals from 65 kindreds were included.

METHODS

The APC gene was screened for mutations using the protein truncation test and heteroduplex analysis. Haplotype analysis was performed with four flanking microsatellite markers. Families that failed to show any mutations were scrutinised with Southern blot hybridisation and allelic expression analysis.

RESULTS

Thirty eight different germline mutations in APC were identified in 47 kindreds (72%). The majority of these mutations were novel and unique to each family. Although sharing the classical polyposis phenotype, families without detectable APC mutations differed from mutation positive families in the following respects: firstly, mean age at polyposis diagnosis was higher (38.6 years (48 individuals) v 30.0 years (140 individuals); p=0.001); and secondly, the proportion of kindreds lacking extracolonic disease was higher (6/18 v. 5/47; p=0.04).

CONCLUSIONS

Our results may pave the way for predictive testing in mutation positive families and should stimulate further molecular studies in mutation negative families. No founder effect was observed, which is in contrast with HNPCC in the same population.

Risk of osteopenia after proctocolectomy and ileal pouch-anal anastomosis for ulcerative colitis

BACKGROUND

The aim of our study was to evaluate the influence of pouchitis and villous atrophy on bone mineral density and metabolism at least 5 years after ileal pouch-anal anastomosis for ulcerative colitis (UC).

METHODS

Eighty-eight subjects with a J-pouch operated on between 1985 and 1994, and 20 ulcerative colitis subjects with a conventional ileostomy were enrolled. Endoscopy was performed and spine and femoral neck bone mineral densities measured. Bone metabolism was assessed by measurement of serum levels of parathyroid hormone, osteocalcin, 25-hydroxyvitamin D3, calcium, alkaline phosphatase and urinary N-telopeptide cross-linked of type I collagen (NTX).

RESULTS

In the lumbar spine, 37% of the J-pouch subjects with subtotal to total villous atrophy had osteopenia (Z score <-1), whereas none of the subjects with normal villous structure had reduced bone densities in the spine or femoral neck. The highest prevalence of osteopenia (66.7%) and the lowest spine (mean -0.89+/-0.36; P = 0.006) and femoral neck (mean -0.63+/-0.29; P = 0.07) Z scores were found among the patients (n = 12) with inflammation in the proximal limb of the pouch. No biochemical parameters were found to predict osteopenia and in stepwise regression analysis, the only independent risk factors for osteopenia were low body mass index and villous atrophy.

CONCLUSIONS

Patients with a J-pouch showing high inflammatory activity and villous atrophy in the pouch need long-term follow-up and should be ensured adequate intake of calcium and vitamin D.

Long term metabolic consequences of ileal pouch-anal anastomosis for ulcerative colitis

OBJECTIVES

Chronic inflammation in the ileal pouch is the most significant late complication after ileal pouch-anal anastomosis (IPAA). It leads to changes in mucosal morphology, with consequent decreased vitamin B12, bile acid and cholesterol absorption documented. The aims of this study were to evaluate long term metabolic consequences at least 5 yr after IPAA and the influence of pouchitis on pouch histology and on bile acid, lipid, and vitamin B12, A, E, and D metabolism.

METHODS

A total of 104 patients with a J-pouch who were operated on between 1985 and 1994, as well as 21 ulcerative colitis patients with a conventional ileostomy were enrolled for the study. Routine blood tests, vitamin status, vitamin B12 levels, and bile acid absorption were determined, as well as endoscopy with biopsies. The pouchitis disease activity index (PDAI) was calculated. On the basis of histology, IPAA patients were divided into three subgroups: 1) those with no villous atrophy, 2) those with partial villous atrophy, and 3) those with subtotal or total villous atrophy.

RESULTS

Incidence of pouchitis was 42.3%, and was strongly associated with villous atrophy. In IPAA patients with subtotal or total villous atrophy (32.7%), serum levels of albumin, calcium, total cholesterol, triglycerides, and vitamin E were significantly reduced (p < 0.05). The lowest bile acid and vitamin B12 absorption rates were seen in patients with inflammation in the proximal limb. Vitamin D deficiency was seen in 10.6%, and vitamin A and B12 deficiency in approximately 5% of IPAA patients.

CONCLUSIONS

Metabolic consequences after IPAA are associated with pouchitis, grade of villous atrophy, and extent of inflammation in the remaining ileum. Patients with active chronic inflammation need long term follow-up.

Dosimetry of beta-ray ophthalmic applicators: comparison of different measurement methods

An international intercomparison of the dosimetry of three beta particle emitting ophthalmic applicators was performed, which involved measurements with radiochromic film, thermoluminescence dosimeters (TLDs), alanine pellets, plastic scintillators, extrapolation ionization chambers, a small fixed-volume ionization chambers, a diode detector and a diamond detector. The sources studied were planar applicators of 90Sr-90Y and 106Ru-106Rh, and a concave applicator of 106Ru-106Rh. Comparisons were made of absolute dosimetry determined at 1 mm from the source surface in water or water-equivalent plastic, and relative dosimetry along and perpendicular to the source axes. The results of the intercomparison indicate that the various methods yield consistent absolute dosimetry results at the level of 10%-14% (one standard deviation) depending on the source. For relative dosimetry along the source axis at depths of 5 mm or less, the agreement was 3%-9% (one standard deviation) depending on the source and the depth. Crucial to the proper interpretation of the measurement results is an accurate knowledge of the detector geometry, i.e., sensitive volume and amount of insensitive covering material. From the results of these measurements, functions which describe the relative dose rate along and perpendicular to the source axes are suggested.

Calculation of beta-ray dose distributions from ophthalmic applicators and comparison with measurements in a model eye

Dose distributions throughout the eye, from three types of beta-ray ophthalmic applicators, were calculated using the EGS4, ACCEPT 3.0, and other Monte Carlo codes. The applicators were those for which doses were measured in a recent international intercomparison [Med. Phys. 28, 1373 (2001)], planar applicators of 106Ru-106Rh and 90Sr-90Y and a concave 106Ru-106Rh applicator. The main purpose was to compare the results of the various codes with average experimental values. For the planar applicators, calculated and measured doses on the source axis agreed within the experimental errors (<10%) to a depth of 7 mm for 106Ru-106Rh and 5 mm for 90Sr-90Y. At greater distances the measured values are larger than those calculated. For the concave 106Ru-106Rh applicator, there was poor agreement among available calculations and only those calculated by ACCEPT 3.0 agreed with measured values. In the past, attempts have been made to derive such dose distributions simply, by integrating the appropriate point-source dose function over the source. Here, we investigated the accuracy of this procedure for encapsulated sources, by comparing such results with values calculated by Monte Carlo. An attempt was made to allow for the effects of the silver source window but no corrections were made for scattering from the source backing. In these circumstances, at 6 mm depth, the difference in the results of the two calculations was 14%-18% for a planar 106Ru-l06Rh applicator and up to 30% for the concave applicator. It becomes worse at greater depths. These errors are probably caused mainly by differences between the spectrum of beta particles transmitted by the silver window and those transmitted by a thickness of water having the same attenuation properties.

Infrequent isolation of multiresistant Acinetobacter baumannii from the staff tending a colonized patient with severe burns

A patient with severe burns who was colonized by multiresistant Acinetobacter baumannii was cared for in contact isolation by staff intensively trained on hospital hygiene. Of the 1,907 postexposure cultures from the staff and 425 environmental samples, only 0.7% and 4%, respectively, yielded this microorganism. These data show that strict hygienic measures may limit staff colonization and contamination of the environment byA baumannii.