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Abstract Purpose To determine the causes of benign hepaticojejunostomy strictures (BHSs) after pancreaticoduodenectomy (PD) and the outcome of endoscopic retrograde cholangiography (ERC) treatment for BHSs. Methods A total of 175 patients who underwent PD between January 2013 and December 2020 and who were followed up for at least 1 year were included. Preoperative data, operative outcomes, and postoperative courses were compared between the BHS group and the group of patients who did not develop stenosis during follow-up (non-BHS group). The course of treatment in the BHS group was also examined. Results BHS occurred in 13 of 175 patients (7.4%). Multivariate analysis of the BHS and non-BHS groups revealed that male sex (OR; 3.753, 95% CI; 1.029–18.003, P = 0.0448) and a preoperative bile duct diameter less than 8.8 mm (OR; 7.51, 95% CI; 1.75–52.40, P = 0.0053) were independent risk factors for the development of BHS. In the BHS group, all patients underwent ERC using enteroscopy. The success rate of the ERC approach to the bile duct was 92.3%. Plastic stents were inserted in 6 patients, and metallic stents were inserted in 3 patients. The median observation period since the last ERC was 17.9 months, and there was no recurrence of stenosis in any of the 13 patients. Conclusions Patients with narrow bile ducts are at greater risk of BHS after PD. Recently, BHS after PD has been treated with ERC-related procedures, which may reduce the burden on patients.

Abstract Background Endoscopic transpapillary gallbladder stenting (EGBS) is considered for patients with contraindications to early surgery for acute calculus cholecystitis. However, evidence regarding the long-term outcomes of EGBS is insufficient to date. The aim of the study was to evaluate the feasibility of EGBS as a bridge to or alternative to surgery when there are contraindications. Methods We reviewed the cases of patients who underwent EGBS using a novel spiral-shaped plastic stent for acute calculus cholecystitis between January 2011 and December 2019. We retrospectively evaluated the long-term outcomes of EGBS using a novel spiral-shaped plastic stent. Results Forty-nine patients were included. The clinical success rate of EGBS was 97%. After EGBS, 25 patients (surgery group) underwent elective cholecystectomy and 24 patients did not (follow-up group). In the surgery group, the median period from EGBS to surgery was 93 days. There was a single late adverse event with cholecystitis recurrence. In the follow-up group, the median follow-up period was 236 days. Late adverse events were observed in eight patients, including recurrence of cholecystitis (four patients), duodenal penetration by the distal stent end (two patients), and distal stent migration (two patient). In the follow-up group, the time to recurrence of biliary obstruction was 527 days. Conclusions EGBS with a novel spiral-shaped plastic stent is safe and effective for long-term acute calculus cholecystitis. There is a possibility of EGBS to be a bridge to surgery and a surgical alternative for acute calculus cholecystitis in patients with contraindications to early cholecystectomy.

Abstract Background Histiocytic sarcoma is a rare malignant tumor that is similar in characteristics to a mature histiocyte/macrophage and is a relatively new disease entity. In approximately one-third of cases, the site of origin is a lymph node; development from the gastrointestinal tract, spleen, soft tissue, and skin has further been reported. The tumor characteristics are not well-understood as reports on its clinical presentation and treatment are limited. We report a case of duodenal primary histiocytic sarcoma. Case presentation An elevated lesion in the second part of the duodenum was detected in a 70-year-old woman during routine examination using upper gastrointestinal tract endoscopy. Blood biochemistry findings were normal for tumor markers. No abnormal findings were observed in the blood count and biochemical examination. Upper gastrointestinal endoscopy revealed a 20-mm elevated lesion with a slight depression in the center, opposite to the papilla of the descending duodenum. The biopsy showed erosions of the mucosal epithelium and inflammatory cell infiltration, but no evidence of malignancy. Ultrasound-guided endoscopy revealed an ischemic tumor of submucosal origin, and bowel biopsy suggested a histiocytic sarcoma. Distant metastasis and lymph node enlargement were absent on abdominal sonography, computed tomography, and magnetic resonance imaging. Duodenal segmental resection was performed. Immunostaining of the excised lesion was positive for CD68, CD163, CD4, CD5, CD15, and CD45 and negative for CD1a, CD21, CD34, MPO, and S-100 protein. Ki-67 positivity was approximately 20%. Based on these findings, the diagnosis of histiocytic sarcoma was confirmed. Ten months after the surgery, a lymph node recurrence in the dorsum of the pancreatic uncus was observed. No evidence of recurrence was found in any other part; hence, we performed pancreaticoduodenectomy. Pathological findings of the excised lymph node confirmed the recurrence of histiocytic sarcoma in the lymph node. Conclusions This is the first reported case of a duodenal primary histiocytic sarcoma with recurrence in the lymph node after the primary resection. The patient was treated for recurrence by lymph node excision and pancreaticoduodenectomy.

Abstract Background This study aimed to investigate whether preoperative muscle mass is associated with the recurrence of distal cholangiocarcinoma after pancreatoduodenectomy (PD). Methods We retrospectively examined 88 patients who had undergone PD for distal cholangiocarcinoma. The preoperative psoas muscle mass index (PMI) was measured using computed tomography as an index of muscle mass. We performed multivariate analysis of factors influencing early recurrence and developed a prognostic survival model using independent risk factors for recurrence. Results The cut-off PMI values for recurrence within 1 year of surgery, determined from the receiver operating characteristic curve, were 5.90 cm2/m2 in males and 3.98 cm2/m2 in females. Multivariate analysis of effects associated with early recurrence within 1 year indicated that low PMI (odds ratio [OR] 9.322; 95% confidence interval [CI] 2.832 − 30.678; p = 0.0002) and lymph node metastasis (OR 5.474; 95% CI 1.620 − 18.497; p = 0.0062) were independent risk factors, and the median recurrence-free survival (RFS) of the low and high PMI groups were 21.6 and 81.0 months, respectively (p = 0.0214). The median RFS for zero, one, and two risk factors of low PMI and lymph node metastasis were as follows: zero variables, median not reached; one variable, 15.3 months; two variables: 6 months. Conclusions Low preoperative PMI may be a risk factor for distal cholangiocarcinoma recurrence after PD. Trial registration The Institutional Review Board of St. Marianna University School of Medicine approved this study prior to commencement of data collection and analysis on October 9, 2020 (IRB no. 5006) and waived the informed consent requirement.

Abstract Background Gallbladder cancer (GBC) with liver metastasis is considered unresectable. However, there have been infrequent reports of long-term survival in patients with GBC and liver metastases. Therefore, we examined the characteristics of long-term survivors of gallbladder cancer with liver metastasis. Methods A retrospective multicenter study of 462 patients with GBC (mean age, 71 years; female, 51%) was performed. Although patients with pre-operatively diagnosed GBC and liver metastasis were generally excluded from resection, some cases identified during surgery were resected. Result In patients with resected stage III/IV GBC (n = 193), the period 2007–2013 (vs. 2000–2006, hazard ratio 0.63), pre-operative jaundice (hazard ratio 1.70), ≥ 2 liver metastases (vs. no liver metastasis, hazard ratio 2.11), and metastasis to the peritoneum (vs. no peritoneal metastasis, hazard ratio 2.08) were independent prognostic factors for overall survival, whereas one liver metastasis (vs. no liver metastasis) was not. When examining the 5-year overall survival and median survival times by liver metastasis in patients without peritoneal metastasis or pre-operative jaundice, those with one liver metastasis (63.5%, not reached) were comparable to those without liver metastasis (40.4%, 33.0 months), and was better than those with ≥ 2 liver metastases although there was no statistical difference (16.7%, 9.0 months). According to the univariate analysis of resected patients with GBC and liver metastases (n = 26), minor hepatectomy, less blood loss, less surgery time, papillary adenocarcinoma, and T2 were significantly associated with longer survival. Morbidity of Clavien–Dindo classification ≤ 2 and received adjuvant chemotherapy were marginally not significant. Long-term survivors (n = 5) had a high frequency of T2 tumors (4/5), had small liver metastases near the gallbladder during or after surgery, underwent minor hepatectomy without postoperative complications, and received postoperative adjuvant chemotherapy. Conclusions Although there is no surgical indication for GBC with liver metastasis diagnosed pre-operatively, minor hepatectomy and postoperative chemotherapy may be an option for selected patients with T2 GBC and liver metastasis identified during or after surgery who do not have other poor prognostic factors.

Adrenal lipoma is a rare, benign tumor, reported to account for 0.7% of primary adrenal tumors. A 69-year-old man presented with left lateral abdominal pain. Computed tomography (CT) was performed, and a huge, irregularly shaped retroperitoneal tumor of uneven internal density was identified, with the border between the tumor and the pancreas and kidney being unclear. Active hemorrhage was also depicted. The tumor consisted mainly of fat, with the exception of the hematoma; it measured 200 mm; and the boundary between it and nearby organs, such as the pancreas, was unclear. Despite angiography being performed twice, the responsible vessel was not identified. Thus, for the purpose of both diagnosis and treatment, we resected the tumor, and considering the possibility of a malignancy, such as liposarcoma, we also resected the pancreatic body and tail and the spleen. The final histopathologic diagnosis was benign adrenal lipoma with hemorrhage, with no invasion to surrounding tissue. Hemorrhage within an adrenal tumor is rare. Most adrenal lipomas are small “incidentalomas” and asymptomatic. With development of a large adrenal lipoma comes the possibility of hemorrhage along with the possibility of features suggestive of malignancy. We encountered a giant adrenal lipoma with hemorrhage and, because of the aforementioned features, performed extended surgical resection, seen in retrospect as oversurgery. The widespread use of CT has led to an increased number of reported cases of adrenal lipoma. We anticipate an accumulation of case reports, which will allow for development of an appropriate treatment algorithm.

Removability is one of the important features of biliary covered self-expandable metal stents (CSEMS). In this study, we evaluated the diagnostic ability of washing cytology of removed CSEMS. For 14 removed CSEMS that had been placed for the biliary strictures (12 malignant, 2 benign), the surface of CSEMS was washed with saline, and pathological examination of the washing liquid as cytology (CSEMS washing cytology) was performed. The specimen sampling rates and sensitivity for malignancy of CSEMS washing cytology were 92.9 % and 41.7 %, respectively. Sensitivity according to the primary disease was 60.0 % for bile duct cancer and 20 % for pancreatic cancer. Sensitivities based on the methods of stent removal were 16.7 % and 66.7 % for removal through the channel of the scope and with the scope, respectively. Therefore, it is possible that sensitivity of CSEMS washing cytology is higher in bile duct cancer and for removal with the scope. In conclusion, CSEMS washing cytology may have potential as a pathological diagnostic method.

Endoscopic transpapillary gallbladder drainage (ETGBD) for acute cholecystitis is challenging. We evaluated the influence of pre-procedural imaging and cystic duct cholangiography on ETGBD. Patients who underwent ETGBD for acute cholecystitis were retrospectively examined. The rate of gallbladder contrast on cholangiography, the accuracy of cystic duct direction and location by computed tomography (CT) and magnetic resonance cholangiopancreatography (MRCP), and the relationship between pre-procedural imaging and the technical success of ETGBD were investigated. A total of 145 patients were enrolled in this study. Gallbladder contrast on cholangiography was observed in 29 patients. The accuracy of cystic duct direction and location (proximal or distal, right or left, and cranial or caudal) by CT were, respectively, 79%, 60%, and 58% by CT and 68%, 55%, and 58% by MRCP. Patients showing gallbladder contrast on cholangiography underwent ETGBD with a significantly shorter procedure time and a lower rate of cystic duct injury. No other factors affecting procedure time, technical success, and cystic duct injury were identified. Pre-procedural evaluation of cystic duct direction and location by CT or MRCP was difficult in patients with acute cholecystitis. Patients who showed gallbladder contrast on cholangiography showed a shorter procedure time and a lower rate of cystic duct injury.

The most common initial strategy for treatment of severe liver trauma is damage control in which hemostasis is achieved by perihepatic gauze packing and/or vascular embolization. However, we encounter patients in whom this strategy alone is not adequate. We have applied the principles of Glissonean pedicle transection, a technique that was originally devised to ensure safe and quick performance of planned hepatectomy for liver cancer, to 3 cases of severe liver trauma. We performed Glissonean pedicle ligation during damage control surgery in 2 patients and Glissonean pedicle transection during the definitive surgery in 1 patient. We describe the approaches and our experience with them, including operation times and outcomes. From our experience thus far, it seems that 8–12 h after the damage control procedure is appropriate for performing the definitive surgery. Although there are some problems posed by this strategy and cases to which it will not be applicable, the method seems to be particularly useful for cases of severe liver trauma in which the damage is extensive and involves the Glissonean pedicles near the hepatic hilus. We describe our 3 cases in detail and review our experience in light of the available literature.

Abstract Background The Kampo medicine bofutsushosan (BTS; Pulvis ledebouriellae compositae; Fang Feng Tong Sheng San) has been used as an anti-obesity treatment in overweight patients. In this study, we assessed the underlying physiological changes induced by BTS in obese mice maintained on a high-fat diet. Methods Male ICR mice were fed a 60% kcal fat diet for 5 weeks starting at 4 weeks of age and then fed the same diet with administration of water (control) or aqueous BTS extract (1.0–2.0 g/kg) for 25 days. Body weight, wet weight of isolated white adipose tissue, and obesity-related serum parameters (glucose, lipids, leptin, adiponectin) were measured after treatment. The mRNA expression levels of leptin, adiponectin, and UCP1 in the adipose tissues were determined by quantitative real-time polymerase chain reaction after the first 5 days of treatment. Results Bofutsushosan (1.5–2.0 g/kg) significantly decreased total body weight and total wet weight of white adipose tissue isolated from subcutaneous (retroperitoneal) and visceral regions (epididymal, mesenteric, and perirenal). At 2.0 g/kg, BTS also decreased total fat mass, visceral fat mass, and ratio of fat mass to body weight as measured by computed tomography, and significantly decreased epididymal adipocyte size after 14 and 25 days’ treatment. Twenty-five days’ treatment lowered serum glucose, insulin, leptin, and triglycerides, and reduced homeostasis model assessment-insulin resistance. Alternatively, 2.0 g/kg BTS significantly increased mRNA levels of adiponectin, leptin, and UCP1 in interscapular brown adipose tissue but not epididymal white adipose tissue after 5 days’ administration. Conclusion In the early administration period, BTS increased mRNA expression levels of leptin, adiponectin, and UCP1 in brown adipose tissues. With longer administration, BTS improved insulin resistance, and subsequently reduced serum levels of leptin and triglyceride in parallel with decreased visceral white adipose tissue volume and adipocyte size.

Background and study aims Biliary plastic stents are generally substituted for gallbladder stents in endoscopic transpapillary gallbladder stenting (EGBS), there is no sufficient evidence about what type of plastic stent is suitable. We examined outcomes of EGBS using standard biliary stents and a novel stent for acute cholecystitis and evaluated the efficacy of the novel stent. Patients and methods Seventy patients with acute cholecystitis in whom EGBS was performed were evaluated retrospectively. We performed EGBS in 23 patients using the novel stent (novel stent group) and 47 patients using standard biliary stents (pigtail: 35, straight: 12) (control group). In the two groups, we examined outcomes of EGBS. Results There were no significant differences in patient backgrounds or rates of technical success, clinical success, or early adverse events (AE) between the novel stent group and the control groups. However, rates of late AEs were 4.3 % in the novel stent group (liver abscess: 1) and 40.4 % in the control group (stent migration: 15, recurrence of cholecystitis: 4), indicating a significantly higher rate in the control group (P = 0.004). The rate of stent migration was significantly higher in the control group (P = 0.006). Multivariate analysis identified a straight type stent as the risk factor for stent migration (odds ratio: 8.81, 95 % confidence interval: 1.66 – 46.83). Conclusions The novel stent had significantly lower rates of late AEs and stent migration. Thus, for long-term stent placement, the novel stent was more effective than traditional biliary stents.

Background/Aims. Endoscopic sphincterotomy (EST) is often performed before fully covered self-expandable metal stent (FCSEMS) placement in order to prevent pancreatitis. However, it is not clear whether EST prevents pancreatitis or affects other adverse events (AEs). This study is conducted to evaluate the necessity of EST before FCSEMS placement for distal malignant biliary strictures due to a pancreatic head tumor. Methods. This study included 68 patients who underwent FCSEMS placement for distal malignant biliary stricture due to a pancreatic head tumor. Treatment outcomes and AEs were retrospectively compared between 32 patients with EST before FCSEMS placement (EST group) and 36 patients without EST (non-EST group). Results. The success rates of drainage for the EST and non-EST groups were 100% and 97.2%, respectively (P=0.95). The incidence of pancreatitis in the EST and non-EST groups was 3.1% and 0%, respectively (P=0.95). The incidence of hyperamylasemia in the EST and non-EST groups was 12.5% and 13.9%, respectively (P=0.85). The incidence of all AEs in the EST and non-EST groups was 15.6% (pancreatitis: 1, cholecystitis: 2, and stent migration: 2) and 13.9% (cholecystitis: 3, stent migration: 2), respectively (P=0.89). Conclusions. EST before FCSEMS placement for distal malignant biliary stricture due to a pancreatic head tumor does not affect the successful drainage and incidence of adverse events. The necessity of EST to prevent pancreatitis before FCSEMS placement was deemed low.

The patient was a 56-year-old woman who had experienced epigastralgia and dorsal pain several times over the last 20 years. She was admitted for a diagnosis of acute cholecystitis, and severe intra- and extrahepatic bile duct dilatation with inner air density was noted. No papilla of Vater was present in the descending duodenum, and 2 small holes were present in the pyloric ring. Bile excretion from one of the small holes was observed under forward-viewing endoscope. It was considered that the pancreatic and bile ducts separately opened into the pyloric ring. Based on these findings, malformation of the pancreaticobiliary duct was diagnosed. She did not wish treatment, but the obstruction associated with duodenal stenosis was noted after 2 years. Pancreatoduodenectomy was performed as curative treatment for duodenal stenosis and retrograde biliary infection through the bile duct opening in the pyloric ring. The ventral pancreas encompassed almost the entire circumference of the pyloric ring, suggesting a subtype of annular pancreas. Generally, lesions are present in the descending part of the duodenum in an annular pancreas, and the pancreatic and bile ducts join in the papillary region. However, in this patient, (1) the pancreas encompassed the pyloric ring, (2) the pancreatic and bile ducts opened separately, and (3) the openings of the pancreatic and bile ducts were present in the pyloric ring. The pancreas and biliary tract develop through a complex process, which may cause various types of malformation of the pancreaticobiliary system, but no similar case report was found on a literature search. This case was very rare and could not be classified in any type of congenital anomaly of the pancreas. We would classify it as a subtype of annular pancreas with separate ectopic opening of the pancreatic and bile ducts into the pyloric ring.

Background/Aims. In early endoscopic retrograde cholangiopancreatography (ERCP) for acute cholangitis due to choledocholithiasis, it is unclear that single-session stone removal can be safely performed. We examined the efficacy and safety of early single-session stone removal for mild-to-moderate acute cholangitis associated with choledocholithiasis. Methods. Among patients with mild-to-moderate acute cholangitis associated with choledocholithiasis who underwent early ERCP (n = 167), we retrospectively compared the removal group (patients who underwent single-session stone removal; n = 78) with the drainage group (patients who underwent biliary drainage alone; n = 89) and examined the effectiveness and safety of single-session stone removal by early ERCP. Results. The patients in the removal group had significantly fewer and smaller stones compared with those in the drainage group. The single-session complete stone removal rate was 85.9% in the removal group. The complication rate in early ERCP was 11.5% in the removal group and 10.1% in the drainage group, with no significant difference (P = 0.963). On comparing patients who underwent early endoscopic sphincterotomy (EST) with those who underwent elective EST after cholangitis had improved, the post-EST bleeding rates were 6.8% and 2.7%, respectively, with no significant difference (P = 0.600). The mean duration of hospitalization was 11.9 days for the removal group and 19.9 days for the drainage group, indicating a shorter stay for the removal group (P < 0.001). In multiple linear regression analysis, stone removal in early ERCP, number of stones, and C-reactive protein level were significant predictors of hospitalization period. Conclusions. Single-session stone removal for mild-to-moderate acute cholangitis can be safely performed. It is useful from the perspective of shorter hospital stay.

Interval appendectomy (IA) for appendiceal abscesses is useful for avoiding extended surgery and preventing postoperative complications. However, IA has problems in that it takes time before an abscess is reduced in size in some cases and in that elective surgery may result in a delay in treatment in patients with a malignant tumor of the appendix. In order to rule out malignancy, we performed colonoscopy on three patients with an appendiceal abscess that did not decrease in size 5 or more days after IA. After malignancy had been ruled out by examination of the area of the appendiceal orifice, the appendiceal orifice was compressed with a colonoscope, and a catheter was inserted through the orifice. Then, drainage of pus was observed from the appendiceal orifice into the cecal lumen. Computed tomography performed 3 days after colonoscopy revealed a marked reduction in abscess size in all patients. No endoscopy-related complication was noted. Colonoscopy in patients with an appendiceal abscess may not only differentiate malignant tumors, but also accelerate reduction in abscess size.

Abstract Rheumatoid arthritis (RA) is a chronic inflammatory synovitis that leads to the destruction of bone and cartilage. The receptor for advanced glycation end products (RAGE) is a multiligand membrane-bound receptor for high-mobility group box-1 (HMGB1) associated with development of RA by inducing production of proinflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1 and IL-6. We developed a bone-targeting therapeutic agent by tagging acidic oligopeptide to a nonmem-brane-bound form of RAGE (endogenous secretory RAGE [esRAGE]) functioning as a decoy receptor. We assessed its tissue distribution and therapeutic effectiveness in a murine model of collagen-induced arthritis (CIA). Acidic oligopeptide-tagged esRAGE (D6-esRAGE) was localized to mineralized region in bone, resulting in the prolonged retention of more than 1 wk. Weekly administration of D6-esRAGE with a dose of 1 mg/kg to RA model mice significantly ameliorated inflammatory arthritis, synovial hyperplasia, cartilage destruction and bone destruction, while untagged esRAGE showed little effectiveness. Moreover, D6-esRAGE reduced plasma levels of proinflammatory cytokines including TNF-α, IL-1 and IL-6, while esRAGE reduced the levels of IL-1 and IL-6 to a lesser extent, suggesting that production of IL-1 and IL-6 reduced along the blockade of HMGB1 receptor downstream signals by D6-esRAGE could be attributed to remission of CIA. These findings indicate that D6-esRAGE enhances drug delivery to bone, leading to rescue of clinical and pathological lesions in murine CIA.

Aims. To evaluate the need for endoscopic sphincterotomy (EST) before covered self-expandable metal stent (CSEMS) deployment for malignant lower biliary stricture with pancreatic duct obstruction. Methods. This study included 79 patients who underwent CSEMS deployment for unresectable malignant lower biliary stricture with pancreatic duct obstruction. Treatment outcomes and complications were compared between 38 patients with EST before CSEMS deployment (EST group) and 41 without EST (non-EST group). Results. The technical success rates were 100% in both the EST and the non-EST group. The incidence of pancreatitis was 2.6% in the EST, and 2.4% in the non-EST group (). The incidences of overall complications were 18.4% and 14.6%, respectively, (). Within the non-EST groups, the incidence of pancreatitis was 0% in patients with fully covered stent deployment and 3.6% in those with partially covered stent deployment (). In the multivariate analysis, younger age (, OR 12) and nonpancreatic cancer (, OR 24) were significant risk factors for overall complications after CSEMS deployment. EST was not identified as a risk factor. Conclusions. EST did not reduce the incidence of pancreatitis after CSEMS deployment in patients of unresectable distal malignant obstruction with pancreatic duct obstruction.

Background and study aims: Many reports have demonstrated the efficacy of endoscopic transpapillary gallbladder stenting (EGBS) for acute cholecystitis (AC), most of which have traditionally used a 7-Fr plastic stent. The study aim was to evaluate the efficacy of a novel 5-Fr plastic stent in EGBS for AC. Patients and methods: We designed a retrospective study that compared the outcomes between 7-Fr and 5-Fr stents in patients undergoing EGBS. Among 147 patients who underwent endoscopic transpapillary gallbladder drainage for AC between January 2019 and July 2023, 104 who underwent EGBS using a 7-Fr (n = 53) or 5-Fr (n = 51) plastic stent were included in the analysis. Results: The technical success rate of EGBS, clinical success rate for AC, and early adverse events (AEs) rate in the 7-Fr and 5-Fr groups were 92.5% vs 100%, 100% vs 98.0%, and 5.7% vs 3.9%, respectively, with no significant differences. However, only in the 7-Fr group, 4 patients failed stent insertion and 3 patients developed postprocedural pancreatitis. Furthermore, the incidence of hyperamylasemia was lower in the 5-Fr group (24.5% vs 9.8%, P = 0.047). The late AE rate did not differ significantly between the 7-Fr and 5-Fr group (14.3% vs 10.0%). The median time to late AE was 238 days for the 7-Fr group and 187 days for the 5-Fr group, with no significant difference. Conclusions: A 5-Fr stent can provide outcomes comparable to those of a 7-Fr stent and help prevent hyperamylasemia.