Flat colorectal cancer precursor lesions: epidemiological aspects and molecular analysis.

Interventions: 1. Clinical data registration;
2. Molecular analysis of polypoid vs. flat colorectal lesions.
Primary outcome(s): 1. Prevalence of flat colorectal lesions in a Dutch population;
2. Clinical characteristics (e.g. location of lesions, percentage of high-grade dysplasia or early cancer);
3. Molecular charcteristics (epigenetic: methylation status and genetic) of flat vs. polypoid colorectal lesions;
4. Prevalence of flat advanced colorectal cancers vs. polypoid advanced colorecal cancers: clinical features of these lesions (e.g. tumor stage);
5. Relation between serrated and adenomatous polyps.
Study Design: Non-randomized controlled trial, Open (masking not used), N/A , unknown, Factorial

干预措施：1. 临床数据登记；2. 息肉样与扁平结直肠病变的分子分析。
主要结局指标：1. 荷兰人群中扁平结直肠病变的患病率；2. 病变的临床特征（例如病变部位、高级别上皮内瘤变或早期癌症的占比）；3. 扁平与息肉样结直肠病变的分子特征（表观遗传学：甲基化状态与遗传学特征）；4. 扁平型进展期结直肠癌与息肉样进展期结直肠癌的患病率，以及此类病变的临床特征（例如肿瘤分期）；5. 锯齿状息肉与腺瘤性息肉的关联。
研究设计：非随机对照试验，开放设计（未采用盲法），不详，未知，析因设计