The adenoma hunt in colorectal cancer screening: defining the target

Abstract

Colorectal adenomas are precursor lesions of colorectal cancer. Different biological and metabolic processes contribute to adenomagenesis. Subsequent progression to carcinoma occurs in only about 5% of the cases. Detection and removal of all adenomas would reduce CRC incidence and mortality, but at the cost of major over-treatment. Classical morphological characteristics fail to accurately discriminate between adenomas that will become malignant and those that will not. Understanding the biology of cancer development will help to better characterize adenomas at high risk of progression, and subsequently establish triage tests that allow to safely reserve colonoscopy only for individuals at high probability of having truly high-risk colorectal adenomas. Screening tests based on genomic changes that affect relevant biological and metabolic processes hold most promise in this respect.

A Randomized, Placebo-Controlled, Preoperative Trial of Allopurinol in Subjects with Colorectal Adenoma

“…Although CRC clinical symptoms develop late, its precursor lesion adenoma can easily be detected (2,3). Because the development of an adenoma into CRC may take an average of 10 to 15 years (2,4), chemoprevention may be a practical approach to reduce CRC incidence (4,5).…”

Sorbitol Dehydrogenase Overexpression and Other Aspects of Dysregulated Protein Expression in Human Precancerous Colorectal Neoplasms: A Quantitative Proteomics Study

“…Early diagnosis of colorectal tumors has been greatly facilitated by screening methods based on fecal analysis or colonoscopy, but both approaches have limitations (5)(6)(7)(8)(9). Better understanding of the molecular mechanisms underlying large bowel tumorigenesis could improve our chances of detecting these lesions in the adenomatous or localized adenocarcinomatous stage, when the chances of successful treatment are greater.…”

Early Detection of Colorectal Cancer and Population Screening Tests

“…Most subjects preferred a shared (54%) or patient-dominant (34%) decision-making process. As previously highlighted, removal of all adenomas, without accurately distinguishing between those which will become malignant and those which will not, will effectively result in excessive overtreatment, and it is for this reason that newer screening tests, such as the sDNA, focusing on genomic changes affecting associated biological and metabolic processes should not be overlooked as options necessitating further research -particularly because of their potential to avoid iatrogenic care, but also because they might better reflect patient preferences for certain population groups (Sillars-Hardebol, et al, 2012).…”