Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Somatic cells accumulate genomic alterations with age; however, our understanding of mitochondrial DNA (mtDNA) mosaicism remains limited. Here we investigated the genomes of 2,096 clones derived from three cell types across 31 donors, identifying 6,451 mtDNA variants with heteroplasmy levels of ≳0.3%. While the majority of these variants were unique to individual clones, suggesting stochastic acquisition with age, 409 variants (6%) were shared across multiple embryonic lineages, indicating their origin from heteroplasmy in fertilized eggs. The mutational spectrum exhibited replication-strand bias, implicating mtDNA replication as a major mutational process. We evaluated the mtDNA mutation rate (5.0 × 10⁻⁸ per base pair) and a turnover frequency of 10–20 per year, which are fundamental components shaping the landscape of mtDNA mosaicism over a lifetime. The expansion of mtDNA-truncating mutations toward homoplasmy was substantially suppressed. Our findings provide comprehensive insights into the origins, dynamics and functional consequences of mtDNA mosaicism in human somatic cells.

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Park SS, et al. Ann Surg Treat Res. 2020 Jul;99(1):44-51. https://doi.org/10.4174/astr.2020.99.1.44

An association between obesity and unfavorable outcomes for various types of malignancy has been established. Nevertheless, the impact of visceral obesity (VO) on outcomes in pancreatic cancer is still unknown and controversial. The aim of this study was to uncover an association between VO and pancreatic cancer outcomes. We retrospectively reviewed 499 patients with pancreatic cancer who were diagnosed and treated in Severance Hospital from January 2006 to December 2011. Compared to the low-VO group (n = 260), the high-VO group (n = 239) was mostly male (68.2% vs. 31.8%, P < 0.001) and was more likely to have current smoking status (29.7% vs. 17.7%, P < 0.001), current alcohol intake status (52.3% vs. 26.4%, P < 0.001) and diabetes mellitus (54.4% vs. 31.9%, P = 0.028). The progression free survival (PFS) and overall survival (OS) were found to be significantly shorter by the Kaplan-Meier method in the high-VO group than in the low-VO group (PFS; P = 0.044, OS: P = 0.013). In addition, the higher percentage of visceral fat was correlated with more lymph node metastasis and shorter OS (P = 0.011 and P = 0.017, respectively). In patients with pancreatic cancer, VO at the time of diagnosis is associated with negative outcomes, such as shorter PFS and OS.

Background: Due to sex‐specific differences in the incidence and clinical and histopathological characteristics of colorectal cancer (CRC), understanding the impact of sex on CRC may suggest sex‐targeted strategies for screening, treatment, and prevention, leading to improved prognosis of CRC. However, there have been few studies investigating the sex‐specific differences in CRC in the Republic of Korea. We aimed to assess sex differences in CRC in the Republic of Korea.Methods: This was a retrospective, multicenter, cohort study of patients diagnosed with CRC between January 2012 and December 2013 at nine hospitals. Patients who had an uncertain CRC stage, were diagnosed with other cancers within 5 years, had carcinoma in situ, non‐epithelial cancer, or primary cancer other than CRC, were excluded. Factors associated with overall survival or progression‐free survival were investigated using Cox regression analysis. Cumulative probability of metachronous lesions was compared using the Kaplan–Meier estimator survival analysis and we compared the survival curves of each group using a log‐rank test. Outcomes were compared using the chi‐square, Fisher's exact, or Student's t‐test, as appropriate.Results: Three thousand one hundred and forteen patients (1999 men, 1315 women) were included. There was no significant difference in the age at onset between men and women. The proportion of patients diagnosed through regular health check‐ups, and asymptomatic at time of diagnosis, was higher in men (48.9% men vs. 42.0% women, p < .001). Rectal cancers were more common in men (38.8% men vs. 31.8% women, p < .001). Right colon cancers were more common in women (31.4% women vs. 22.7% men, p < .001). KRAS mutations were found in 109/317 (34.4%) women and 112/480 (23.3%) men. Overall CRC survival and progression‐free survival were similar in both sexes.Conclusion: Sex differences in CRC may be due to the biological and social‐behavioral differences between the sexes. They should be considered during screening, diagnosis, and treatment of CRC for better outcomes.