BACKGROUND:

Self-expandable metallic stent (SEMS) placement is widely carried out for distal malignant biliary obstruction, and survival analysis is used to evaluate the cumulative incidences of SEMS dysfunction (e.g. the Kaplan-Meier [KM] method and the log-rank test). However, these statistical methods might be inappropriate in the presence of 'competing risks' (here, death without SEMS dysfunction), which affects the probability of experiencing the event of interest (SEMS dysfunction); that is, SEMS dysfunction can no longer be observed after death. A competing risk analysis has rarely been done in studies on SEMS.

PATIENTS AND METHODS:

We introduced the concept of a competing risk analysis and illustrated its impact on the evaluation of SEMS outcomes using hypothetical and actual data. Our illustrative study included 476 consecutive patients who underwent SEMS placement for unresectable distal malignant biliary obstruction.

RESULTS:

A significant difference between cumulative incidences of SEMS dysfunction in male and female patients via theKM method (P = 0.044 by the log-rank test) disappeared after applying a competing risk analysis (P = 0.115 by Gray's test). In contrast, although cumulative incidences of SEMS dysfunction via the KM method were similar with and without chemotherapy (P = 0.647 by the log-rank test), cumulative incidence of SEMS dysfunction in the non-chemotherapy group was shown to be significantly lower (P = 0.031 by Gray's test) in a competing risk analysis.

CONCLUSION:

Death as a competing risk event needs to be appropriately considered in estimating a cumulative incidence of SEMS dysfunction, otherwise analytical results may be biased.

BACKGROUND:

Several clinical studies of prophylactic therapy for esophageal varices have led to the conclusion that prophylactic therapy is of no value, and it is generally not accepted in the Western world. However, this is not the case in Japan. The present study evaluated the efficacy of prophylactic endoscopic injection sclerotherapy (EIS) in patients with unresectable hepatocellular carcinoma (HCC) and risky esophageal varices.

PATIENTS AND METHODS:

Twenty-seven patients with 'likely-to-bleed' esophageal varices concomitant with unresectable HCC were randomly allocated to two groups. Thirteen patients underwent prophylactic EIS (EIS group), whereas the remaining 14 patients were observed conservatively (control group).

RESULTS:

No bleeding from esophageal varices occurred in the EIS group during the entire period of this study, whereas in thecontrol group the cumulative bleeding rate was 44.8% in 6 months. Cumulative survival rates of patients in the EIS group and in the control group were 48.8% and 7.7% in 2 years, respectively. There was a statistically significant difference between the two groups in cumulative bleeding rate and survival rate (P < 0.01).

CONCLUSION:

This prospective study demonstrated that prophylactic EIS could prolong the survival of the patients with esophageal varices concomitant with unresectable HCC. Prophylactic EIS for patients with unresectable HCC may be, in part, justified according to the present study.

Endoscopic treatment is now recognized worldwide as the first-line treatment for bile duct stones. Endoscopic sphincterotomy combined with basket and/or balloon catheter is generally carried out for stone extraction. However, some stones are refractory to treatment under certain circumstances, necessitating additional/other therapeutic modalities. Large bile duct stones are typically treated by mechanical lithotripsy. However, if this fails, laser or electrohydraulic lithotripsy (EHL) is carried out under the guidance of conventional mother-baby cholangioscopy. More recently, direct cholangioscopy using an ultrathin gastroscope and the newly developed single-use cholangioscope system - the SpyGlass direct visualization system - are also used. In addition, extracorporeal shock wave lithotripsy has also been used for stone fragmentation. Such fragmentation techniques are effective in cases with impacted stones, including Mirizzi syndrome. Most recently, endoscopic papillary large balloon dilationhas been introduced as an easy and effective technique for treating large and multiple stones. In cases of altered anatomy, it is often difficult to reach the papilla; in such cases, a percutaneous transhepatic approach, such as EHL or laser lithotripsy under percutaneous transhepatic cholangioscopy, can be a treatment option. Moreover, enteroscopy has recently been used to reach the papilla. Furthermore, an endoscopic ultrasound-guided procedure has been attempted most recently. In elderly patients and those with very poor general condition, biliary stenting only is sometimes carried out with or without giving subsequent dissolution agents.

Conventionally, long-segment Barrett's esophagus (LSBE) has been considered a high-risk background for the occurrence of Barrett's adenocarcinoma in Western countries, and random biopsy has been proposed for surveillance, aiming to detect early cancer. However, accurate detection of a lesion and diagnosis of the expansion are difficult by this blind method. Herein, we report a case of early Barrett's adenocarcinoma derived from LSBE thatwas successfully detected by narrow-band imaging with magnifying endoscopy.

We herein report a rare case of very small Barrett's adenocarcinoma. A 65-year-old man underwent surveillance esophagogastroduodenoscopy (EGD) 3 years after endoscopic submucosal dissection (ESD) for superficial Barrett's adenocarcinoma, which revealed a very small reddish area in the mucosa, 2 mm in diameter, in long-segment Barrett's esophagus. The EGD carried out 1 year later confirmed slight enlargement of the lesion, from 2 mm to 3 mm in diameter. Macroscopic type changed from flat type to slightly depressed type. On narrow-band imaging with magnifyingendoscopy, an irregular microstructure and irregular microvasculature became recognizable. It was resected by ESD and diagnosed as mucosal adenocarcinoma with a diameter of only 3 mm.

We report herein a case of adenocarcinoma arising from short-segment Barrett's esophagus (SSBE) in a 36-year-old man. An elevated tumor was found at the esophagogastric junction, and a histological evaluation of the biopsy specimen led to a diagnosis of adenocarcinoma. The tumor was found to be confined to the mucosa surrounding the SSBE, and endoscopic submucosal dissection was done without complications. Histological examination of the resected specimen showed that the adenocarcinoma had also invaded the muscularis mucosae and provided evidenceof lymphovascular invasion. Additional surgical resection and regional lymph node dissection were therefore carried out; however, no lymph node metastasis was found. Adenocarcinoma arising from Barrett's mucosa is rare in young patients, especially in Japan, and this case is therefore particularly noteworthy.

A 40-year-old man was referred to our hospital for detailed examination of a protuberant lesion in long-segment Barrett's esophagus (LSBE). Under white light endoscopy (WLE) the lesion appeared as a protuberant lesion with a rough surface and was diagnosed as 0-IIa-type tumor suspected to be a well-differentiated adenocarcinoma. A regular villous pattern was shown in the background mucosa of the LSBE by narrow-band imaging (NBI) magnifying endoscopy (NBI-ME). However, a slightly irregular villous pattern was observed on the lateral side of the main lesion. Therefore, a 0-IIa-type tumor was estimated to have a flatly lateral extension component (i.e. 0-IIb spreading). The 0-IIb spreading was unclear when using WLE, but could be diagnosed by NBI-ME based on the surface pattern differences. Markings were placed outside the edge of the flatly lateral extension, and endoscopic submucosal dissection was carried out.The pathological diagnosis of the protuberant lesion with flatly lateral spreading was well-differentiated adenocarcinoma. The macroscopic type was 0-IIa+IIb, 45 × 43 mm in size. The invasion depth was T1a (deep muscularis mucosae). Lymphatic and venous invasions were negative; horizontal and vertical margins were negative. In conclusion, NBI-ME was useful for the diagnosis of the flatly lateral extension of this 0-IIa+IIb esophageal adenocarcinoma in Barrett's esophagus. Further investigations with many cases are necessary.

A 36-year-old man complained of heartburn. Gastrointestinal endoscopies showed a reddish and slightly depressed lesion in the right-anterior wall of the esophagogastric junction. With white light imaging, the area of the adenocarcinoma under the squamous epithelium was difficult to detect, but a slightly flat, elevated lesion appeared in the area of adenocarcinoma under the squamous epithelium. With narrow-band imaging (NBI) in the area of the Barrett's esophageal cancer under the squamous epithelium, a slight, brownish change could be observed. In addition, with the magnifying technique, irregular mesh-like vessels were observed, suggesting the presence of differentiatedadenocarcinoma under the squamous epithelium. The lesion was resected en bloc by endoscopic submucosal dissection, and Barrett's esophageal cancer under the squamous epithelium was histologically confirmed. In this case, NBI with magnifying endoscopy was very useful to diagnose the extension of Barrett's esophageal cancer under the squamous epithelium.