Association between Vitamin D Receptor Single-Nucleotide Polymorphisms and Colorectal Cancer in the Thai Population: A Case-Control Study.

Vitamin D and its cognate intracellular nuclear receptor, namely, vitamin D receptor (VDR), are involved in the regulation of a variety of body metabolic processes, immune function, and oncogenesis. A large number of studies demonstrated the association of low vitamin D levels and variations in five common single nucleotide polymorphisms (SNPs), FokI, BsmI, Tru9I, ApaI, and TaqI, with the risk of several cancers, including colorectal cancers. However, these associations vary among different populations. This case-control study was aimed at analysing whether common single-nucleotide polymorphisms (SNPs) and haplotypes of the vitamin D receptor (VDR) gene contribute to colorectal carcinogenesis in the Thai population. We enrolled 364 Thai participants from King Chulalongkorn Memorial Hospital between 2014 and 2015. Half of the participants underwent colonoscopy and showed a normal colon without polyps (control group) and another half were newly diagnosed patients with colorectal cancer (CRC) by colonoscopy during the index period, were under treatment, or were followed up at the outpatient clinic (case group). Differences in allele and genotype frequencies of five common VDR SNPs, between the case and control groups, were the primary outcome measures. Differences in haplotype frequencies of the five SNPs between the case and control groups were the secondary outcome measures. Among the 364 participants, baseline characteristics were not significantly different between the case and control groups, except for the higher proportion of males in the CRC group. The mean vitamin D level was also not significantly different between the case and control groups (24.6 ± 9.1 vs. 25.3 ± 10.6 ng/mL, p = 0.52). None of the five VDR SNPs was associated with CRC development (p > 0.05). However, haplotype analysis of these polymorphisms demonstrated that the AGGT haplotype was associated with a decreased risk of CRC (odds ratio 0.24, 95% confidence interval 0.07-0.81, p = 0.01). The AGGT haplotype was associated with a lower risk of CRC in the Thai population. This genetic linkage might support the role of vitamin D in colorectal carcinogenesis. However, this finding requires further study within a larger population and a multivariate analysis of other established risk factors.

Polypectomy for Recurrent Inflammatory Cap Polyposis Combined with Argon Plasma Coagulation.

A 15-year-old adolescent boy presented with chronic constipation, difficulty in defecation, and episodic bloody stools. A rectal mass lesion was digitally palpated. Colonoscopy showed a large circumferential polypoid lesion of the mid-rectum. Snare polypectomy was performed, and histopathology confirmed a diagnosis of benign inflammatory cap polyposis. At 3-month follow-up, sigmoidoscopy showed multiple recurrences of polyps at the site of the previous rectal polypectomy, which were removed by combined hot snare polypectomy and argon plasma coagulation. At 1-year follow-up, the patient was symptom-free and had no more episodes of bloody stool. Follow-up sigmoidoscopy showed a post-polypectomy rectal mucosal scar without recurrent polypoid lesions.

Liver Fluke-Associated Biliary Tract Cancer.

Cholangiocarcinoma (CCA) is an aggressive cancer arising from epithelial cells of the bile duct. Most patients with CCA have an unresectable tumor at the time of diagnosis. In Western countries, the risk of CCA increases in patients with primary sclerosing cholangitis, whereas liver fluke infection appears to be the major risk factor for CCA in Asian countries. A diagnosis of liver fluke infection often relies on stool samples, including microscopic examination, polymerase chain reaction-based assays, and fluke antigen detection. Tests of serum, saliva and urine samples are also potentially diagnostic. The presence of liver fluke along with exogenous carcinogens magnifies the risk of CCA in people living in endemic areas. The "liver fluke-cholangiocarcinoma" carcinogenesis pathways consist of mechanical damage to the bile duct epithelium, immunopathologic and cellular reactions to the liver fluke's antigens and excretory/secretory products, liver fluke-induced changes in the biliary tract microbiome and the effects of repeated treatment for liver fluke. A vaccine and novel biomarkers are needed for the primary and secondary prevention of CCA in endemic areas. Importantly, climate change exerts an effect on vector-borne parasitic diseases, and awareness of liver fluke should be enhanced in potentially migrated habitat areas.

Uncomplicated common bile duct stone removal guided by cholangioscopy versus conventional endoscopic retrograde cholangiopancreatography.

BACKGROUND: Although previous studies have reported the possibility of therapeutic ERCP without fluoroscopy, more robust documentation of fluoroscopy-free common bile duct stone (CBDS) clearance is needed. Technically, "digital cholangioscopy" (DCS) may be used to confirm CBDS clearance. We aimed to compare the feasibility, safety, and radiation exposure between patients with CBDS undergoing stone removal by DCS and conventional ERCP (cERCP). METHODS: Fifty (50) consecutive patients with a CBDS size < 15 mm underwent DCS (SpyGlass DS Direct Visualization System, Boston Scientific, Marlboro, MA, USA) between December 2015 and October 2016. Of 202 consecutive patients undergoing cERCP during the same time frame, 50 matched pairs were created using propensity score matching analysis. In the DCS group, patients underwent biliary cannulation and CBDS removal without fluoroscopy followed by DCS to confirm complete CBDS clearance. A final occlusion cholangiogram was performed as the current standard of care to confirm CBDS clearance. RESULTS: Cannulation success rates were similar between the DCS and cERCP groups (98 vs. 98%). By intention-to-treat analysis, CBDS clearance in the DCS and cERCP groups was not different (90 vs. 98%; p = 0.20, respectively). DCS had successful CBDS removal in 45 cases, whereas 5 (10%) failed for clearance by DCS due to technical limitations. Adverse events were not different between both groups. CONCLUSIONS: In the management of uncomplicated CBDS, our data confirmed the feasibility of DCS for CBDS clearance as it showed efficacy and safety comparable to those of cERCP. Although certain conditions may limit its effectiveness, DCS offers the ability to perform CBDS clearance without the need for fluoroscopy unit and can avoid radiation exposure while ERCP under fluoroscopy remains the current standard of care in patients with CBDS.