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Background The routine collection of large amounts of clinical data, 'big data', is becoming more common, as are research studies that make use of these data source. The aim of this paper is to provide an overview of the uses of data from large multi-institution clinical databases for research. Methods This article considers the potential benefits, the types of data source, and the use to which the data is put. Additionally, the main challenges associated with using these data sources for research purposes are considered. Results Common uses of the data include: providing population characteristics; identifying risk factors and developing prediction (diagnostic or prognostic) models; observational studies comparing different interventions; exploring variation between healthcare providers; and as a supplementary source of data for another study. The main advantages of using such big data sources are their comprehensive nature, the relatively large number of patients they comprise, and the ability to compare healthcare providers. The main challenges are demonstrating data quality and confidently applying a causal interpretation to the study findings. Conclusion Large clinical database research studies are becoming ubiquitous and offer a number of potential benefits. However, the limitations of such data sources must not be overlooked; each research study needs to be considered carefully in its own right, together with the justification for using the data for that specific purpose. [ABSTRACT FROM AUTHOR]

Background The optimal management of colorectal cancer with synchronous liver metastases has not yet been elucidated. The aim of the present study was systematically to review current evidence concerning the timing and sequence of surgical interventions: colon first, liver first or simultaneous. Methods A systematic literature review was performed of clinical studies comparing the timing and sequence of surgical interventions in patients with synchronous liver metastases. Retrospective studies were included but case reports and small case series were excluded. Preoperative and intraoperative data, length of hospital stay, perioperative mortality and morbidity, and 1-, 3- and 5-year survival rates were compared. The studies were evaluated according to a modification of the methodological index for non-randomized studies ( MINORS) criteria. Results Eighteen papers were included and 21 entries analysed. Five entries favoured the simultaneous approach regarding duration of procedure, whereas three showed no difference; five entries favoured simultaneous treatment in terms of blood loss, whereas in four there was no difference; and all studies comparing length of hospital stay favoured the simultaneous approach. Five studies favoured the simultaneous approach in terms of morbidity and eight found no difference, and no study demonstrated a difference in perioperative mortality. One study suggested a better 5-year survival rate after staged procedures, and another suggested worse 1-year but better 3- and 5-year survival rates following the simultaneous approach. The median MINORS score was 10, with incomplete follow-up and outcome reporting accounting primarily for low scores. Conclusion None of the three surgical strategies for synchronous colorectal liver metastases appeared inferior to the others. [ABSTRACT FROM AUTHOR]

Background: Optical techniques using previously unexploited properties of light interaction with tissue may be valuable in the detection, diagnosis and staging of colorectal neoplasia. Methods: A Medline search (1990 to present) was conducted on optical diagnostics in the detection of colorectal neoplasia. The reference list of each identified article was reviewed for further relevant papers. Results and conclusion: Chromoendoscopy is the only optical adjunct to colonoscopy that has been tested in large randomized clinical trials. It improves the detection of small and flat colorectal adenomas, and of neoplasia in chronic ulcerative colitis and hereditary non-polyposis colorectal cancer. All other techniques are the subject of ongoing research and the practicality of population screening with any of the methods has yet to be established. Optical techniques may, however, permit immediate clinical diagnosis, removing the need for histological analysis. They may also improve the diagnosis of early colonic neoplasia. Copyright © 2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background and method: This paper reviews the current status of radiofrequency ablation in the treatment of colorectal liver metastases. Relevant studies with at least ten patients that reported rates of complete tumour ablation, local recurrence, or survival from 1 to 5 years after treatment were included in the review. Results and conclusion: Only six studies that reported at least 3-year survival were identified, with results ranging from 37 to 58 per cent. Some of these figures are promising, given that the patients were considered to have unresectable disease. However, available evidence is limited and hepatic resection remains the standard of care when feasible; radiofrequency ablation cannot be considered an equivalent. Radiofrequency ablation does, however, appear to have a role in treating unresectable disease, and may also be used in conjunction with resection to extend its limits. [ABSTRACT FROM AUTHOR]

Background: Cyclo-oxygenase inhibition for the treatment of colorectal neoplasia has been studied with renewed interest since the discovery of cyclo-oxygenase (Cox) 2 and the introduction of specific Cox-2 inhibitors. These drugs have implications for both the prevention of colorectal carcinoma and the potential treatment of the disease. Methods and results: A Medline database search was performed for articles using the keywords 'colonic, colon or rectal and neoplasia or cancer' and 'cyclo-oxygenase or Cox-2.' Cross-references of relevant historical papers were also included. There is substantial evidence that Cox-2 plays a role in the development and progression of colorectal cancer. The specific inhibition of this enzyme has been shown to inhibit cancer growth in in vitro and in vivo models. The mechanisms of action for these effects are poorly understood and potential clinical applications at present remain under investigation. Conclusion: Cox-2 inhibitors have great promise as useful additions to current cancer treatments. There is a need for randomized clinical trials to define a role for these drugs in chemoprevention, recurrence prophylaxis, and adjuvant therapy for colorectal and other solid tumours. [ABSTRACT FROM AUTHOR]

Background: This paper reports a 7-year experience of cryoablation for colorectal and non-colorectal liver metastases. Methods: A retrospective review was undertaken of patients treated in two adjacent UK centres in the north-west of England. Results: Over a 7-year period (1993-2000), 57 patients underwent cryotherapy for malignant hepatic tumours (41 colorectal, 16 non-colorectal). In the patients with colorectal metastases, preoperative carcinoembryonic antigen (CEA) levels fell significantly, from a mean of 444.1 to 6.22 μg/1 (P = 0.002). One patient died, two developed cryoshock and six had cardiorespiratory complications. All patients with colorectal metastases subsequently received 5-fluorouracil-based chemotherapy. The remaining 16 patients with non-colorectal tumours (seven neuroendocrine metastases, five hepatocellular carcinomas, three sarcomas, one cholangiocarcinoma) all received cryotherapy alone, with no major complications. The median survival for patients with non-colorectal metastases was 37 months, compared with 22 months for those with colorectal metastases (P = 0.005). Conclusion: Hepatic cryotherapy is effective and safe, as demonstrated by the significant reduction in postoperative CEA concentration and the low risk of complications. However, this initial short-term success was not reflected in 5-year survival rates. Cryotherapy for non-colorectal metastases had a greater long-term survival benefit and is a useful means of controlling symptoms. [ABSTRACT FROM AUTHOR]

Background: Hereditary non-polyposis colorectal cancer (HNPCC) is an inherited genetic condition associated with microsatellite instability; it accounts for around 5 per cent of all cases of colorectal cancer. This review examines recent data on management strategies for this condition. Methods: A Medline-based literature search was performed using the keywords 'HNPCC' and 'microsatellite instability'. Additional original papers were obtained from citations in articles identified by the initial search. Results and conclusion: The Amsterdam criteria identify patients in whom the presence of an inherited mutation should be investigated. Those with a mutation should be offered counselling and screening. The role of prophylactic surgery has been superseded by regular colonoscopy, which dramatically reduces the risk of colorectal cancer. Screening for extracolonic malignancy is also advocated, but the benefits are uncertain. Chemoprevention may be of value in lowering the incidence of bowel cancer in affected patients, but further studies are required. [ABSTRACT FROM AUTHOR]

Background: It is widely accepted that the adenoma–carcinoma sequence represents the process by which most, if not all, colorectal cancers arise. The evidence supporting this hypothesis has increased rapidly in recent years and the purpose of this article is to review this evidence critically and highlight its clinical significance. Methods: Medline searches were used to identify recent key articles relating to the adenoma–carcinoma sequence. Further pertinent articles were obtained by manual scanning of the reference lists of identified papers. Results: The evidence supporting the adenoma–carcinoma sequence can be classified as epidemiological, clinicopathological and genetic. The most recent and largest body of data relates to molecular genetic events and their cellular effects; however, many other approaches, such as cytogenetics, molecular cytogenetics and cytometry, have also yielded valuable information. Conclusion: Recent work continues to support the adenoma–carcinoma sequence, but there is a paucity of data on the interrelationship between different genetic mutations and on the relationship between molecular and other types of genetic abnormalities. The clinical utility of the observations described has yet to be fully realized and global genetic analysis of colorectal tumours may prove to be central in rational adenoma management. [ABSTRACT FROM AUTHOR]

Background Advances in molecular pathology have enabled a number of colorectal cancer antigens to be identified and characterized. The commonest investigated include 17-1A, 791Tgp72 and carcinoembryonic antigen. Vaccines have been developed that stimulate the immune system to target these antigens. This paper reviews current areas of research in this field. Methods and Results Relevant articles were obtained on vaccines for colorectal cancer from Medline and the Bath Information Data System. A number of approaches are currently being evaluated in Phase I, II and III trials. These include anti-idiotypic antibody immunization, DNA vaccines, mucin and heat shock protein-based vaccines, oncogenes and viral vectors. Conclusion Evidence is accumulating to suggest that immune responses may be generated against colorectal cancer using these approaches. While the concept of vaccination against this malignancy is essentially experimental, surgeons should be aware of current advances. [ABSTRACT FROM AUTHOR]