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Cancer Biomarkers
Published in Trevor F. Cox, Medical Statistics for Cancer Studies, 2022
We need to think about the population we are dealing with and there is a difference between a biomarker for screening a population where individuals do not have symptoms of cancer and a population of individuals who do have symptoms of possible cancer. For example, the UK bowel cancer screening programme screens all (consenting) adults over the age of 50 for bowel cancer, with each person tested every two years until the age of 75. There is no screening programme for prostate cancer. The population for testing a biomarker for prostate cancer might be all men who have symptoms that make them contact their GP for discussion about prostate cancer. A sample of men from the population might be selected to test a new potential biomarker, where each man has the biomarker measured as well a gold standard test to establish the cancer/ no cancer state. This would be a cohort study (see Chapter 7). Another type of study would be a case-control study (see Chapter 7), where a sample of men with prostate cancer is selected (cases) and a sample of men without prostate cancer is selected (controls). One problem with a case-control study is that if you only select men with well established prostate cancer, the gold-standard test being nearly reliable in the detection of the cancer, then if you show that your new biomarker is good at detecting the cancer. That is excellent news for men in the more advanced stages of the cancer, but will it work for those men in the early stages of prostate cancer?
General Surgery
Published in Tjun Tang, Elizabeth O'Riordan, Stewart Walsh, Cracking the Intercollegiate General Surgery FRCS Viva, 2020
Rebecca Fish, Aisling Hogan, Aoife Lowery, Frank McDermott, Chelliah R Selvasekar, Choon Sheong Seow, Vishal G Shelat, Paul Sutton, Yew-Wei Tan, Thomas Tsang
Tell me briefly about the NHS Colorectal Screening Programme.Bowel cancer screening started in England in 2006 for 60–69-year olds on a biennial basis, using guaiac faecal occult testsThis has now been expanded to 60–74 years old in England, although screening starts at the age of 50 in Scotland.The guaiac test has largely been superseded by faecal immunochemical tests (FIT) which are at least as sensitive as guaiac-based tests and identify precursors of colorectal cancer earlier, have higher uptake and detect human haemoglobin. (FIT replaced guaiac testing in England in 2018.)Bowel scope is a new screening test in addition to faecal occults tests and invites all 55-year-old men and women for a one-off flexible sigmoidoscopy.If positive patients are reviewed in a screening clinic and consented regarding the risks and benefits of a colonoscopy to reach a definitive diagnosis.
Pathology and Staging of Colorectal Adenoma and Adenocarcinoma
Published in Peter Sagar, Andrew G. Hill, Charles H. Knowles, Stefan Post, Willem A. Bemelman, Patricia L. Roberts, Susan Galandiuk, John R.T. Monson, Michael R.B. Keighley, Norman S. Williams, Keighley & Williams’ Surgery of the Anus, Rectum and Colon, 2019
It is believed that around 17% of cancers detected by bowel cancer screening were polyp cancers, and nearly half (48%) of invasive lesions detected were Dukes’ Stage A.4 With screening there is earlier detection of Dukes ‘A’ lesions and significant downstaging of cancer compared to non-screened populations, and this highlights the benefit of screening programmes (see Chapter 26 of this section). The majority of polyps in screening series in the UK NHS Bowel Cancer Screening Programme (BCSP) have been classified as tubular adenomas (48%–55%), with less incidence of tubulovillous (15%–24%) and purely villous (1%–6%) types. The reported prevalence of high-grade dysplasia has varied between 5%–14%, and adenocarcinoma is present in approximately 5%–7%. Higher rates of malignancy have been described in purely villous adenomas (10%–18%) compared with tubular (2%–3%) and tubulovillous (6%–8%) types and correlate with increasing polyp size and grade of dysplasia.8
How could brain fingerprinting lead to the early detection of mental illness in adolescents and what are the next steps?
Published in Expert Review of Neurotherapeutics, 2023
As suggested above, brain fingerprinting is anticipated to be a key component of the personalized mental health landscape. In the context of youth mental health, such AI-based predictive technology could greatly help young people and their families make informed decisions about potential risk for MHPs – working with clinicians to make early interventions and track brain changes that ensue. The evidence would suggest that an ideal time to undertake such predictive measurement is at the beginning of adolescence, around the time of puberty. Such screening could take place at the population level, that is, all individuals at ~12 years of age are provided with the opportunity to undertake a government-funded brain scan utilized to predict mental health risks. This concept is not dissimilar to something like bowel cancer screening for all individuals aged 50–74 years [12].
Computer-aided classification of colorectal segments during colonoscopy: a deep learning approach based on images of a magnetic endoscopic positioning device
Published in Scandinavian Journal of Gastroenterology, 2023
Britt B. S. L. Houwen, Fons Hartendorp, Ioanis Giotis, Yark Hazewinkel, Paul Fockens, Taco R. Walstra, Evelien Dekker
This study was designed to evaluate the diagnostic accuracy of deep learning models for the classification of the colorectal segment, based on images of the MEI positioning device. The study is reported according to the STARD statements [18]. For this study we used the data of a prospective multicenter study in which a computer-aided diagnosis (CADx) for optical diagnosis of diminutive polyps was developed, validated and benchmarked against the performance of screening endoscopists (POLyp Artificial Recognition [POLAR] system) (Houwen B, 2022, unpubl. data). This study was conducted from October 2018 to September 2021 in eight regional Dutch hospitals and one academic Spanish hospital in partnership with ZiuZ Visual Intelligence (Gorredijk, the Netherlands). Data were collected during colonoscopies in the context of the bowel cancer screening and surveillance program or for the evaluations of symptoms. The detailed methods and results of this study are described elsewhere (online). For this study, we used prospectively collected training data from one center in which the MEI device was used during the study procedures.
Implications of colonic and extra-colonic findings on CT colonography in FIT positive patients in the Dutch bowel cancer screening program
Published in Scandinavian Journal of Gastroenterology, 2021
Marieke H. A. Lammertink, Jelle F. Huisman, Marie L. E. Bernsen, Ronald A. M. Niekel, Henderik L. van Westreenen, Wouter H. de Vos tot Nederveen Cappel, Bernhard W. M. Spanier
Our study is the first study that reports the intra- and extra-colonic findings in a FIT positive national bowel cancer screening population. Our CRC or AA detection rate, 4.9% and 13.8% respectively, is comparable to Plumb et al. and substantially lower compared to the yield of colonoscopy in our national bowel screening program (8% CRC and 42% AA) [4,11]. There are several explanations for this. Differences between the size of the lesion on CTC and colonoscopy might alter the intra-colonic detection rate. Small lesions on CTC can be missed, as CTC is less sensitive in detecting small lesions; 16.9% of the patients in our study with suspected relevant lesions on CTC did not undergo additional endoscopy; furthermore, AA is defined by a tubulovillous histology which can be found in adenomas <10 mm. The question is whether the lower detection rate observed in bowel screening programs has an impact on the life expectancy of patients with serious morbidity. The proportion of patients that did not undergo further investigation in our study is high (16.9%); however, the intra-colonic findings of CTC in these patients with severe co-morbidity most likely do not alter their life expectancy. Also, missed small lesions on CTC will probably not alter life expectancy in this study population. We demonstrated that 70% of the patients had no suspicious intra-colonic findings and could be reassured. In patients that underwent CTC instead of colonoscopy, an additional endoscopy was performed in 28.4% for histological diagnosis or treatment of colonic lesions detected on CTC.