Backgrounds/Aims: Calcium is a preventive factor for colorectal cancer, which develops from colorectal adenoma. This study aimed to investigate the association between dietary calcium intake and prevalence of colorectal adenoma among Korean adults. Methods: Overall, 612 participants aged ≥ 20 years who underwent gastrointestinal endoscopy at 8 medical centers from 2021 to 2023 were included. Dietary calcium intake was assessed using a food frequency questionnaire and was energy-adjusted using the residual model. Multivariate logistic regression models were used to calculate for the odds ratios (ORs) and 95% confidence intervals (CIs). The associations between dietary calcium intake and colorectal adenoma prevalence were also assessed according to the anatomic subsites and adenoma status (advanced or nonadvanced). Results: Among the 612 participants, 269 were diagnosed with colorectal adenoma (170 men and 99 women). With respect to the gender-specific association, low dietary calcium intake was associated with higher prevalence of colorectal adenoma among men (ORs [95% CIs]: 2.13 [0.50-9.00] for < 250 mg/day; 3.53 [1.06-11.76], 250 to < 350 mg/day; and 1.84 [0.63-5.35], 350 to < 650 mg/day, compared to ≥ 650 mg/day of dietary calcium [p for trend = 0.07]). Similar association was observed among women, but neither the association nor trend was statistically significant (p for trend = 0.59). These inverse associations remained similar for distal colon/rectal adenoma among women and advanced adenoma among men. Conclusions: Low dietary calcium intake was associated with high colorectal adenoma prevalence, particularly among men. Given the limited number of studies among Asian populations, our findings should be replicated in other Asian groups.

Total gastrectomy has been a standard treatment for upper-third early gastric cancer for decades. Supplementation is essential after total gastrectomy due to vitamin B12 deficiency. Additionally, postoperative complications, such as reflux esophagitis, anastomotic stricture, leakage, and malnutrition, are the main issues. Proximal gastrectomy is considered an alternative treatment for upper-third early gastric cancer. As a function-preserving gastrectomy it is known that the incidence of vitamin B12 deficiency is low and due to its various reconstruction methods we can easily overcome major postoperative complications. Therefore, we aimed to review about proximal gastrectomy, how it is reconstructed, and complications after reconstruction.

Esophageal squamous cell carcinomas constitute a major proportion of esophageal cancers in Korea. Conventional chemotherapy and radiation therapy are the options for treating advanced/metastatic esophageal cancer, but the prognosis remains poor. Immunotherapy has significantly improved the prognosis of several advanced/metastatic cancers including esophageal squamous cell carcinoma. In Korea, immunotherapy is used to treat advanced/metastatic esophageal squamous cell carcinoma, and treatment results are expected to further improve. Immunotherapy is a term used to describe a treatment modality involving a biological/targeted agent that aims to enhance and restore the ability of the immune system to detect and destroy cancer cells by modifying or blocking co-stimulating signals. Immune checkpoint inhibitors have revolutionized cancer treatment with the administration of a single agent (monotherapy) or combinations of multiple agents, with the three approved agents being anti-PD-1 (programmed death 1), anti-PD-L1 (programmed cell death ligand 1), and anti-CTLA4 (cytotoxic T-lymphocyte-associated protein 4) monoclonal antibodies. Anti-PD-1 drugs including nivolumab and pembrolizumab have been mainly investigated for treating advanced/metastatic esophageal squamous cell cancer. Studies on their effectiveness in a neoadjuvant setting, a curative adjuvant setting, or as the first-line treatment for advanced or metastatic setting are ongoing. This review describes the principle of action, summary of existing clinical studies, and prospects for immune checkpoint inhibitors used in the treatment of advanced/metastatic esophageal squamous cell cancer.

The increasing prevalence of obesity globally underscores its pivotal role in the development of colorectal cancer (CRC). Epidemiological evidence consistently correlates obesity with CRC, implicating intricate pathways such as insulin resistance, chronic inflammation, and hormonal dysregulation. Understanding the impact of obesity on CRC recurrence, therapeutic efficacy, and overall survival is paramount. Lifestyle modifications, including weight reduction, offer promising avenues for mitigating CRC risk. Recognizing obesity as a modifiable risk factor highlights its importance in shaping CRC prevention and therapeutic paradigms.

The incidence of colon cancer in South Korea has recently been the highest among gastrointestinal cancers. Early diagnosis is critical, and image-enhanced endoscopy (IEE) is a key diagnostic method. Colon tumors primarily include serrated polyps, adenomatous polyps, and colon cancer. Early endoscopic techniques relied on simple visual inspection for diagnosis, with tumor size and shape being the primary considerations. Low-resolution images made these methods ineffective for detecting small or early-stage lesions. IEE now enables detailed examination using high-resolution images and various color and structure analyses. Techniques like narrow band imaging (NBI) allow precise observation of vascular patterns and surface structures. Hyperplastic polyps often appear similar in color to the surrounding mucosa, with no visible vascular pattern. Sessile serrated lesions have a cloudy surface with distinct boundaries and irregular patterns, often with black spots in the crypts. Adenomatous polyps are darker brown, with a visible white epithelial network and various pit patterns. Magnified images help differentiate between low- and high-grade dysplasia, with low-grade showing regular patterns and high-grade showing increased irregularities. The NBI International Colorectal Endoscopic classification identifies malignant colon tumors as brown or dark brown with disorganized vascular patterns. The Japan NBI Expert Team classification includes loose vascular areas and disrupted thick vessels. The Workgroup serrAted polypS and Polyposis classification aids in differentiating between hyperplastic polyps and sessile serrated lesions/adenomas when deciding whether to resect polyps larger than 5 mm. Suspected high-grade dysplasia warrants endoscopic submucosal dissection and follow-up. Future advancements in IEE are expected to further enhance early detection and diagnostic accuracy.

Chronic pancreatitis, a significant risk factor for pancreatic cancer, necessitates monitoring for pancreatic cancer development. Chronic pancreatitis can be broadly categorized into hereditary and sporadic. Given the variability in the risk for pancreatic cancer based on the presence and type of genetic mutations, it is crucial to establish and be aware of guidelines for screening and surveillance tailored to each risk level. In cases of hereditary chronic pancreatitis with PRSS1 mutations, patients demonstrated a high incidence of pancreatic cancer, justifying the rationale for screening and surveillance. However, the incidence of pancreatic cancer is relatively low in hereditary chronic pancreatitis with other genetic mutations and sporadic chronic pancreatitis; thus, precise screening and periodic surveillance are not recommended. For individuals with PRSS1 mutation-related hereditary chronic pancreatitis, surveillance may be considered from the age of 40 years. While computed tomography or magnetic resonance imaging is suitable for pancreatic cancer screening, endoscopic ultrasonography is not recommended because of parenchymal inflammation, fibrosis, and calcification. However, in cases of sporadic chronic pancreatitis where various risk factors for pancreatic cancer coexist, the incidence of pancreatic cancer significantly increases. Therefore, in 5 years after the diagnosis of chronic pancreatitis, the pancreatic cancer incidence has been observed to continuously increase. In such cases, individualized screening tests and surveillance based on the patient's symptoms and specific circumstances must be considered.

Circulating tumor cells (CTCs) are a valuable biomarker for the diagnosis, prognosis, and therapeutic management of gastrointestinal (GI) cancers. A major challenge in GI cancer treatment is the high rate of metastasis, which significantly contributes to cancer-related mortality. CTCs are crucial in the metastatic cascade, serving as indicators of tumor progression. Therefore, the detection and molecular characterization of CTCs have prognostic potential for identifying early-stage GI cancers and assessing metastatic probability, enabling timely treatment. Moreover, CTC analysis offers a minimally invasive method for real-time monitoring of tumors. Clinicians can adjust therapeutic strategies accordingly by tracking changes in CTC count and molecular profile. Despite this promising application, no standardized protocol for CTC isolation in GI tract cancers has been established, which poses a barrier to routine clinical use. This review explores the current CTC detection methodologies, their clinical relevance in GI cancer management, and the potential integration of CTC analysis into personalized medicine. We also discuss the challenges and future directions in CTC research, focusing on clinical validation and the development of standardized procedures to fully realize the utility of CTC count for improving patient care.

The incidence of hepatocellular carcinoma (HCC) is continuously increasing worldwide, with approximately 1 million new cases expected annually by 2025. Data from the Korean Central Cancer Registry in 2023 revealed that the survival rate of patients with HCC was only 40%, unlike patients with other major cancers with a 5-year survival rate of up to 80%, highlighting the need for improved outcomes. The prognosis of HCC significantly changed following research on immune checkpoint inhibitors (ICIs). Several studies have demonstrated that the overall survival of patients treated with first-line combination therapies, such as atezolizumab (anti-PD-L1) and bevacizumab (anti-VEGF) or durvalumab (anti-PD-L1) and tremelimumab (anti-CTLA-4), was higher than that of patients treated with sorafenib. Research to identify biomarkers that can predict ICI responses is ongoing, enabling the selection of suitable patients before drug initiation. Moreover, studies of the tumor microenvironment in HCC enhance our understanding of immune responses, helping us identify new therapeutic strategies. Additionally, clinical trials are being conducted for emerging immunotherapies beyond ICIs, such as adoptive cell therapy. Based on these ongoing scientific researches and the development of various therapeutic modalities, multiple options are being established for patients with HCC who do not respond well to first-line treatments. Consequently, treatment options and survival rates of patients with advanced HCC could be significantly enhanced in the future.

Fournier's gangrene (FG) is a necrotizing fasciitis of the perianal, perineal, and genital regions, leading to necrosis of the fascia and subcutaneous tissue. It is a rare condition, particularly when induced by rectal cancer. Herein, we present a rare case in which FG was discovered incidentally during the physical examination of a patient who complained of general weakness. The patient was diagnosed with FG induced by rectal cancer with liver metastasis and underwent laparoscopic diverting loop ileostomy instead of abdominoperineal resection (APR). After 13 rounds of chemotherapy over 9 months, the condition of the rectal cancer partially improved. Furthermore, FG lesions showed improvement with this treatment plan compared to the initial treatment with dressings and antibiotics. Therefore prompt surgical intervention is important for treating FG induced by rectal cancer.