Colorectal Cancer Screening—Who, How, and When?

Abstract

Colorectal cancer (CRC) is the third most common cancer worldwide. It is amenable to screening as it occurs in premalignant, latent, early, and curable stages. PubMed, Cochrane Database of Systematic Reviews, and national and international CRC screening guidelines were searched for CRC screening methods, populations, and timing. CRC screening can use direct or indirect tests, delivered opportunistically or via organized programs. Most CRCs are diagnosed after 60 years of age; most screening programs apply to individuals 50–75 years of age. Screening may reduce disease-specific mortality by detecting CRC in earlier stages, and CRC incidence by detecting premalignant polyps, which can subsequently be removed. In randomized controlled trials (RCTs) guaiac fecal occult blood testing (gFOBt) was found to reduce CRC mortality by 13%–33%. Fecal immunochemical testing (FIT) has no RCT data comparing it to no screening, but is superior to gFOBt. Flexible sigmoidoscopy (FS) trials demonstrated an 18% reduction in CRC incidence and a 28% reduction in CRC mortality. Currently, RCT evidence for colonoscopy screening is scarce. Although not yet corroborated by RCTs, it is likely that colonoscopy is the best screening modality for an individual. From a population perspective, organized programs are superior to opportunistic screening. However, no nation can offer organized population-wide colonoscopy screening. Thus, organized programs using cheaper modalities, such as FS/FIT, can be tailored to budget and capacity.

Simulated performance of flexible sigmoidoscopy-based screening for advanced neoplasia detection in a Greek population

“…Indeed, reaching the splenic flexure (FS-2) may not be feasible in a substantial proportion of patients undergoing FS in practice, because of inadequate enema preparation (vs. oral bowel cleansing administered for colonoscopy) and the absence of intravenous sedation. According to our data, limiting the insertion depth of FS to the sigmoid-descending Table 5 Estimated sensitivities of flexible sigmoidoscopy-based screening for advanced colorectal neoplasia assuming different colonoscopy referral criteria in the total population and stratified by sex UK criteria [6] Source criteria [9] NORCCAP criteria [9] PLCO criteria [8] F S-1 Thirdly, the overall detection rate of adenomas in this study was apparently low, falling short of the recommended 25% threshold [34]. This could potentially be attributed to a variety of factors, including a demographic mix predominantly comprising younger (50-59 years) women, exclusive use of standard-definition colonoscopes in years 2014-2016, and the inclusion of procedures with suboptimal bowel preparation, as we did not use a validated scale to rate colonic cleanliness.…”

Fecal Genetic Mutations and Human DNA in Colorectal Cancer and Polyps Patients

“…According to the Globocan 1.800.000 new cases of CRC and 881.000 deaths occurred (Bray et al, 2018). Although most studies shown decreased mortality from CRC after screening methods, studies should consider adherence to invasive tests, side effects and cost (Richter, 2008, Bevan andRutter, 2018).…”

Preventing colorectal cancer in Sri Lanka: step forward

“…Randomized trials show favourable results (6-7), with risk reduction of 18% in incidence and 28% in deaths related to colorectal cancer (8). Further, FS has a higher detection rate of advanced neoplasia Samarakoon Y. JCCPSL 2020, 26 (1) Open Access compared to gFOBT or FIT, but a lower specificity and sensitivity than colonoscopy for both advanced adenomas and neoplasm (9). Colonoscopy is considered the gold standard for colorectal cancer screening, which could detect and resect neoplasia and precancerous lesions across the entire large bowel.…”