Management of early colonic neoplasia: where are we now and where are we heading?

Introduction: There have been considerable advances in the endoscopic treatment of colorectal neoplasia. The development of endoscopic submucosal dissection and full thickness resection techniques is changing the way benign disease and early cancers are managed. This article reviews the evidence behind these new techniques and discusses where this field is likely to move in the future.

Areas covered: A PubMed literature review of resection techniques for colonic neoplasia was performed. The clinical and cost effectiveness of endoscopic mucosal resection (EMR) is examined. The development of endoscopic submucosal dissection (ESD) and knife assisted resection is described and issues around training reviewed. Efficacy is compared to both EMR and transanal endoscopic microsurgery. The future is considered, including full thickness resection techniques and robotic endoscopy.

Expert commentary: The perceived barriers to ESD are falling, and views that such techniques are only possible in Japan are disappearing. The key barriers to uptake will be training, and the development of educational programmes should be seen as a priority. The debate between TEMS and ESD will continue, but ESD is more flexible and cheaper. This will become less significant as the number of endoscopists trained in ESD grows and some TEMS surgeons may shift across towards ESD.     

Decreased copy‐neutral loss of heterozygosity in African American colorectal cancers

Despite improvements over the past 20 years, African Americans continue to have the highest incidence and mortality rates of colorectal cancer (CRC) in the United States. While previous studies have found that copy number variations (CNVs) occur at similar frequency in African American and White CRCs, copy‐neutral loss of heterozygosity (cnLOH) has not been investigated. In the present study, we used publicly available data from The Cancer Genome Atlas (TCGA) as well as data from an African American CRC cohort, the Chicago Colorectal Cancer Consortium (CCCC), to compare frequencies of CNVs and cnLOH events in CRCs in the two racial groups. Using genotype microarray data, we analyzed large‐scale CNV and cnLOH events from 166 microsatellite stable CRCs—31 and 39 African American CRCs from TCGA and the CCCC, respectively, and 96 White CRCs from TCGA. As reported previously, the frequencies of CNVs were similar between African American and White CRCs; however, there was a significantly lower frequency of cnLOH events in African American CRCs compared to White CRCs, even after adjusting for demographic and clinical covariates. Although larger differences for chromosome 18 were observed, a lower frequency of cnLOH events in African American CRCs was observed for nearly all chromosomes. These results suggest that mechanistic differences, including differences in the frequency of cnLOH, could contribute to clinicopathological disparities between African Americans and Whites. Additionally, we observed a previously uncharacterized phenomenon we refer to as small interstitial cnLOH, in which segments of chromosomes from 1 to 5 Mb long were affected by cnLOH.