BACKGROUND & AIMS:Most colorectal cancers (CRC) arise from colorectal adenomas, yet there is not enough information on global prevalence to inform health care policy. We examined the prevalence of any type of adenomas, advanced adenomas (AADs), and CRC according to age, sex, ethnicity, geographic regions, and anatomic location (proximal vs distal). METHODS:MEDLINE and Embase were searched from their inception through May 1, 2018, to identify population-based, observational studies that reported the prevalence of colorectal neoplasia. Studies on participants 15 years or older, with a sample size of 500 persons or more, were included. Metaprop (College Station, TX) was used to model within-study variability by binomial distribution and Freeman-Tukey Double Arcsine Transformation to stabilize the variances. The prevalence figures were presented by proportions and their 95% CIs using random-effects models. RESULTS:Our meta-analysis included 70 studies involving 637,414 individuals. The overall prevalence rates of adenoma (23.9%; 95% CI, 22.2%-25.8%), AAD (4.6%; 95% CI, 3.8%-5.5%), and CRC (0.4%, 95% CI, 0.3%-0.5%) were calculated. Subgroup analysis indicated that prevalence values (adenomas, AADs, and CRCs) were higher among men (29.7%, 6.5%, and 0.8%, respectively) than women (19.3%, 3.8% and 0.4%, respectively), among older adults (25.9%, 5.2%, and 0.6%, respectively) than younger adults (14.6%, 1.6%, and 0.1%, respectively), among Caucasians (23.7%, 6.6%, and 0.5%, respectively) than other ethnicities, in European countries (25.9%, 8.4%, and 0.8%, respectively) than other countries, and among patients with proximal (25.9%, 5.3%, and 0.1%, respectively) vs distal neoplasia. CONCLUSIONS:In a systematic review and meta-analysis, we found a high prevalence of colorectal neoplasia among some populations. This indicates a need to expand CRC screening programs for these groups. The pooled prevalence estimates can be used as quality indicators for established CRC screening programs.

Sarcomas are a key feature of Li-Fraumeni and related syndromes (LFS/LFL), associated with germline TP53 mutations. Current penetrance estimates for TP53 mutations are subject to significant ascertainment bias. The International Sarcoma Kindred Study is a clinic-based, prospective cohort of adult-onset sarcoma cases, without regard to family history. The entire cohort was screened for mutations in TP53 using high-resolution melting analysis and Sanger sequencing, and multiplex-ligation-dependent probe amplification and targeted massively parallel sequencing for copy number changes. Pathogenic TP53 mutations were detected in blood DNA of 20/559 sarcoma probands (3.6%); 17 were germline and 3 appeared to be somatically acquired. Of the germline carriers, one appeared to be mosaic, detectable in the tumor and blood, but not epithelial tissues. Germline mutation carriers were more likely to have multiple cancers (47% vs 15% for non-carriers, P = 3.0×10−3), and earlier cancer onset (33 vs 48 years, P = 1.19×10−3). The median survival of mutation carriers following first cancer diagnosis was not significantly different from non-carriers. Only 10/17 (59%) pedigrees met classical or Chompret criteria for LFS. In summary, germline TP53 mutations are not rare in adult patients with sarcoma, with implications for screening, surveillance, treatment and genetic counselling of carriers and family members.

Objective This study aimed to evaluate how the knowledge and perception towards colorectal cancer (CRC) screening had been changed in a large population, and identified factors associated with its participation based on factors pertinent to the Health Belief Model (HBM). Methods Data from 3600 screening participants and 3600 non‐participants were collected through a telephone survey via simple random sampling of telephone numbers in a territory‐wide directory from December 2016 to November 2018. Sociodemographic factors; the enabling factors of screening as well as the barriers of screening were collected. The changes in these factors were evaluated by Pearson's chi‐square trend test. A logistic regression model was constructed to identify the association between the above factors and CRC screening participation. Results The knowledge level (67.9% to 85.4%, p < 0.001), perceived severity of having CRC (37.7%–42.8%, p < 0.01), perceived benefits of screening (54.9%–72.1%, p < 0.001), and reductions in barriers (14.1%–5.1%, p < 0.001) of CRC screening significantly improved among the non‐users. Subjects with older age (adjusted odds ratio (AOR): 2.01, p < 0.001), higher knowledge level of screening methods (AOR: 6.68, p < 0.001), greater perceived severity (AOR: 2.04, p < 0.001) and coverage of insurance (AOR: 1.22, p < 0.01) were more likely to participate. In contrast, more affluent subjects (AOR: 0.69, p < 0.001), female individuals (AOR: 0.63, p < 0.001), higher level of perceived psychological (AOR: 0.54, p < 0.001) and access barriers (AOR: 0.55, p < 0.001) were associated with poorer participation. Conclusion These findings demonstrated a substantial increase in the enabling factors of CRC screening, including knowledge, perceived severity and perceived benefits. The study also identified the target groups such as younger individuals, females and more affluent people among whom more intensive educational initiatives are needed to enhance their participation.