Colorectal cancer screening

Abstract

Abstract. Bretthauer M (Oslo University Hospital, Oslo, Norway). Colorectal cancer screening (Review). J Intern Med 2011; 270: 87-98. Colorectal cancer (CRC) is the third most common cause of cancer death worldwide and a major health problem. In this review, the different approaches for CRC screening will be outlined with emphasis on evidence-based medicine. Evidence from randomized trials on the effectiveness of CRC screening is summarized. Several screening tools for CRC are available. They can be categorized according to their mode of action: early detection tools such as the faecal occult blood test (FOBT) and cancer prevention tools such as flexible sigmoidoscopy and colonoscopy. Metaanalyses of randomized trials show that FOBT screening reduces CRC mortality by 16% (risk ratio 0.84; 95% confidence interval (CI) 0.78-0.9) compared with 30% (risk ratio 0.7; 95% CI 0.6-0.81) for flexible sigmoidoscopy screening. FOBT screening is cheap and noninvasive, but results in large numbers of false-positive tests and needs to be repeated frequently. Flexible sigmoidoscopy is more invasive, but is effective for once-only screening. Although colonoscopy screening is used in some countries, no randomized trials have been conducted to estimate its benefit, and therefore, it should not be recommended at the present time. Faecal occult blood test and flexible sigmoidoscopy are the two CRC screening tools that can be recommended as they have been proven to reduce CRC mortality. Colonoscopy has the potential to be superior to FOBT and flexible sigmoidoscopy, but needs to be evaluated in randomized trials before any recommendation can be provided.

Familial colorectal cancer screening: When and what to do?

“…It has been estimated that a small adenoma needs at least 10 years to become a cancer [7] . Thus, screening programs are aimed to identify these preneoplastic lesions using different tools, such as fecal occult blood test (FOBT), sigmoidoscopy, and colonoscopy.…”

“…Screening programs are based on the assumption that the vast majority of CRCs develop from a benign precursor lesion, such as adenoma, through a series of genetic changes over a long-time period (adenoma-carcinoma sequence) [7,34] . It has been estimated that a small adenoma needs at least 10 years to become a cancer [7] .…”

“…The estimated Italian median annual incidence rate in 2010 was 88.8 cases per 100000 individuals among men and 70.3 cases per 100000 among women per year [6] . The lifetime risk of CRC for average-risk subjects in industrialized countries is about 5% [1,7] , but it increases 2-4-fold if there is a family history of CRC [8] . Studies in kindred and twins estimated that approximately 30% of all cases of CRC occur in patients with a family history of CRC, but only 2%-5% of cases of inherited CRC are caused by a syndrome-related to a Mendelian pattern of inheritance [8][9][10][11][12] .…”

RON - The Con in Colorectal Carcinoma

“…Although a number of screening *Address correspondence to this author at the Eppley Institute for Research in Cancer and Allied Diseases University of Nebraska Medical Center Omaha, Nebraska 68198, USA; Tel: 402-559-5558; Fax: 402-559-4651; E-mail: jjwang@unmc.edu methods have been developed, their effectiveness is limited due to lack of awareness and financial constraints [19,20]. Metastasis largely determines the survival time of patients and accounts for the majority of CRC deaths [21].…”

Aberrant DNA methylation of tumor‐related genes in oral rinse

“…If signs of cancer are detected, then more definitive and invasive follow-up tests are performed to reach a diagnosis. Noninvasive screening tests for several cancers have been established and are used worldwide; eg, the fecal occult blood test for colorectal cancer, 3 barium sulfate examination for gastric cancer, 4 and mammography for breast cancer screening. 5 However, a similarly useful, noninvasive test for oral cancer has not yet been established.…”