Impact of COVID-19 on gastric cancer treatment in Japanese high-volume centers: a JCOG stomach cancer study group survey.

PURPOSES: The spread of coronavirus disease 2019 (COVID-19) has affected socioeconomic and healthcare systems in many countries. Accordingly, many individuals may have canceled their annual health-check programs, including esophagogastroduodenoscopy, which would have resulted in lower numbers of newly diagnosed patients with gastric cancer in comparison to other times. METHODS: Questionnaires were distributed to 62 hospitals every week from May 2020 to August 2020 (total 744) through mailing lists of the Stomach Cancer Study Group of the Japan Clinical Oncology Group. The number of patients with gastric cancer and hospital systems during the COVID-19 pandemic were surveyed. RESULTS: In total, 74% (551 out of 744) of the questionnaires were answered and analyzed. In early May, approximately 50% of hospitals had to restrict surgical slots due to the COVID-19 pandemic. However, they gradually loosened the restrictions thereafter. The number of gastrectomies was < 80% that of the same period in the previous year, and hospitals in Tokyo were seriously affected by a 50% decrease in the number of gastrectomies. CONCLUSIONS: The number of gastrectomies was lower than that in the previous year. Further multi-center follow-up studies are required to evaluate the long-term effects of COVID-19 on the clinical outcomes of patients with gastric cancer.

[Hepatic Portal Vein Gas during Chemotherapy for Esophageal Cancer-A Report of Four Cases].

Case 1, a man in his 70s, was admitted because of a bleeding gastric ulcer during DCF therapy for esophageal cancer(EC). Three days after endoscopic hemostasis, abdominal pain and vomiting occurred.CT revealed hepatic portal venous gas (HPVG).No intestinal necrosis was observed on contrast-enhanced CT.Therefore, we selected a conservative treatment and found improvement.Case 2, a man in his 70s, developed frequent diarrhea during DCF therapy for EC.Case 3, a man in his 80s, developed hematochezie during DCF therapy for EC.Both cases 2 and 3 were diagnosed as HPVG using abdominal ultrasonography.The symptoms were mild, so we selected a conservative treatment and found improvement.Case 4, a man in his 60s, noticed sudden severe abdominal pain during DGS therapy for EC.Plain CT detected HPVG and gas in the small intestinal wall.We suspected intestinal necrosis due to HPVG with peritoneal irritation and performed emergency small intestine resection.We encountered 4 patients who developed HPVG during chemotherapy.The presence of HPVG is a poor prognostic sign, suggestive of intestinal necrosis, but some patients show improvement with conservative treatments.We also discuss previous reviews and reports.

The inhibition of thymidine phosphorylase can reverse acquired 5FU-resistance in gastric cancer cells.

BACKGROUND: 5FU can be converted to its active metabolite fluoro-deoxyuridine monophosphate (FdUMP) through two pathways: the orotate phosphoribosyl transferase-ribonucleotide reductase (OPRT-RR) pathway and the thymidine phosphorylase-thymidine kinase (TP-TK) pathway. We investigated the mechanism underlying 5FU-resistance, focusing on the changes in the 5FU metabolisms. METHODS: MKN45 and 5FU-resistant MKN45/F2R cells were treated with 5FU or fluoro-deoxyuridine (FdU) in combination with hydroxyurea (HU) or tipiracil (TPI). The amount of FdUMP was determined by the density of the upper band of thymidylate synthase on Western blotting. RESULTS: The MKN45/F2R cells exhibited 5FU resistance (37.1-fold) and showed decreased OPRT and increased TP levels. In both cells, the FdUMP after treatment with 5FU was decreased when RR was inhibited by HU but not when TP was inhibited by TPI. A metabolome analysis revealed the loss of intracellular deoxyribose 1-phosphate (dR1P) in both cells, indicating that FdUMP was synthesized from 5FU only through the OPRT-RR pathway because of the loss of dR1P. After the knockdown of TK, the FdUMP after treatment with FdU was decreased in MKN45 cells. However, it was not changed in MKN45/F2R cells. Furthermore, TP inhibition caused an increase in FdUMP after treatment with 5FU or FdU and reversed the 5FU resistance in MKN45/F2R cells, indicating that FdUMP was reduced through the TP-TK pathway in MKN45/F2R cells. CONCLUSIONS: In MKN45/F2R cells, the reduction of FdUMP through the TP-TK pathway caused 5FU resistance, and the inhibition of TP reversed the resistance to 5FU, suggesting that the combination of 5FU and TPI is a promising cancer therapy.

Questionnaire survey on adjuvant chemotherapy for elderly patients after gastrectomy indicates their vulnelabilities.

BACKGROUND: In Japan, S-1 adjuvant chemotherapy for 1 year is the standard of care for the treatment of stage II and III patients under 80 years old with gastric cancer after curative operation. However, the feasibility of S-1 chemotherapy in patients over 80 years old has not yet been elucidated. METHODS: To clarify the current treatment situation and feasibility of S-1 treatment in patients over 80 years old, a questionnaire survey of the patients treated from January 2011 to December 2012 was conducted at 58 member institutions of the Stomach Cancer Study Group of the JCOG (Japan Clinical Oncology Group). RESULTS: Gastrectomy was performed in 15,573 patients of all ages, and 1,660 (10.7%) patients were over 80 years of age. Of these elderly patients, 661 (4.2%) were diagnosed as stage II and III. While S-1 adjuvant chemotherapy was recommended to 248 (37.5%) of the stageII/III patients, only 99 (15.0%) of them actually received S-1. Interestingly, the creatinine clearance rate was between 30 and 80 mL/min in 87 (87.9%) of the patients suggesting that S-1 dose modification should be considered. Moreover, S-1 compliance was poor in patients with more than 15% body weight loss. CONCLUSION: In general practice, surgery alone can be regarded as the standard of care for stage II and III gastric cancer patients over 80 years old. The feasibility and efficacy of S-1 adjuvant chemotherapy should be elucidated in a randomized control trial considering the vulnerabilities of the elderly.

Single-incision laparoscopic ileocecal resection in a 10-year-old child with appendiceal neuroendocrine tumor.

BACKGROUND: In Japan, the majority of gastrointestinal tract neuroendocrine tumors (NETs) have been reported to originate from the rectum, and appendiceal NETs are relatively rare. Preoperative diagnosis is very difficult and it is diagnosed after appendectomy. Pediatric appendiceal NET is a disease with a good prognosis. However, in rare cases, lymph node metastasis could occur and additional resection is required. CASE PRESENTATION: A 10-year-old boy complained of right lower quadrant abdominal pain and underwent an appendectomy under a diagnosis of acute appendicitis in previous hospital. The final diagnosis was appendiceal NET, so he was referred to our department for additional resection. The tumor was found in the base of the appendix and invasively reached the subserosal layer with obvious vascular invasion. His Ki-67 index was 1 to 2%, so we classified it as appendiceal NET G1 according to the WHO 2015 classification. We considered the possibility of a tumor remnant or lymph node metastasis, so we performed single-incision laparoscopy with D3 lymph node dissection. The pathological diagnosis revealed no tumor remnant but metastasis to one lymph node. He was discharged on the 9th postoperative day. There has been no recurrence at 3 years and 7 months after surgery. CONCLUSION: When the tumor size is 10-20 mm, the frequency of lymph node metastasis in some reports is variable, and there is no consensus yet on the indications for additional resection. However, there are definitely a certain number of cases with lymph node metastasis that require additional resection. In the present patient, long-term survival can be obtained by additional resection. At present, factors such as the presence of vascular or lymph node invasion and the malignancy grade and tumor's location must be considered on a case-by-case basis. Although the incidence rate of appendiceal NET is rare, the diagnosis can be made only during postoperative pathological examination; thus, reliable histopathological examination is required.

The long-term survival of stage IV gastric cancer patients with conversion therapy.

PURPOSE: A retrospective study was performed to clarify the role of conversion therapy (surgery with a prospect of R0 resection performed in initially unresectable metastatic cancer that responded to the chemotherapy) in stage IV gastric cancer (GC). PATIENTS AND METHODS: We treated 259 stage IV GC patients with systemic chemotherapy at Gifu and Hiroshima University Hospitals between 2001-2013. Of these, 84 patients who were subsequently treated by surgery were classified into four categories according to our previously published classification of stage IV GC, and short- and long-term outcomes were analyzed. RESULTS: Surgery was performed in 84 patients, of which 7 were performed following the neoadjuvant chemotherapy, whereas the other 77 that excluded neoadjuvant chemotherapy cases were considered the conversion therapy. The postoperative mortality and morbidity were comparable with those reported clinical trials. The MSTs of the patients with/without surgery for each category were 28.3/5.8 months for category 1, 30.5/11.0 months for category 2, 31.0/18.5 months for category 3 and 24.7/10.0 months for category 4. The MST of the R0 resected patients (41.3 months) was far better than that of the R1-2 resected patients (21.2 months). The MSTs of the patients with R0/R1-2 resection were 56.2/16.3 months for category 2, 33.3/29.6 months for category 3 and 40.7/17.8 months for category 4. CONCLUSION: There were long-term survivors who underwent conversion therapy for stage IV GC. Adequate selection of stage IV GC patients for conversion therapy may be an important role for the surgical oncologist in the new era.

[A Case of Metastatic Colorectal Cancer with Brain Metastasis Treated with Combined TFTD and Bevacizumab Therapy].

A woman in her 70s was confirmed as presenting with multiple liver and lung metastases from transverse colon cancer. After undergoing resection of the primary lesion, partial response(PR)was achieved after undergoing the first regimen (sLV5FU2 and bevacizumab[Bmab]); therefore, partial hepatectomy was performed. Adjuvant chemotherapy was administered for 7 months, but liver metastasis recurrence, multiple lung metastases, and brain metastasis were confirmed. As the brain metastasis was a single lesion and was accompanied by symptoms, resection of the lesion was performed. Treatment with regorafenib was initiated, but Grade 3 severe erythema multiforme was detected, and the treatment had to be discontinued. Therefore, combined TFTD and Bmab therapy was initiated as the third regimen. Liver and lung metastases were maintained as stable disease(SD), and the treatment was continued for approximately 1 year together with stereotaxic radiation therapy for the newbrain metastatic lesion. The utility of combined TFTD and Bmab therapy has been reported in a phase II trial, and it has also been indicated that Bmab is effective for reducing brain edema. As this treatment was effective in this case, we will report on it together with a discussion of the literature.

[Experience with Nivolumab in the Treatment of Metastatic Gastric Cancer].

Immunological checkpoint inhibitors have effects on various advancedcancers. Nivolumab was approvedfor advanced gastric cancer after third-line treatment in 2017. In our hospital, 10 patients were treatedwith nivolumab from October 2017 to March 2018. Thus, we retrospectively examinedthe clinical background, treatment outcomes, andad verse events of those patients. The median age was 70 years; male-to-female ratio was 6:4; recurrence sites were peritoneal dissemination, liver, lymph nodes, brain, ovaries, and bone(8, 2, 2, 1, 1, and1 , respectively); andtreatment lines were third, fourth, andfifth(in 6, 3, and1 patients, respectively). The minimum number of cycles was 1 course, while the maximum was 11 courses. The best tumor response evaluation was SD, andthe adverse event was an itching sensation in only one patient. It was suggestedthat long-term SD couldbe maintainedwhen the nivolumab treatment was initiatedin a patient with goodPS. In the future, biomarker analysis is expectedto identify effective cases.

[A Case of Stage IV Gastric Cancer Curative Resection by Conversion Therapy].

We experienced a case of curative resection as a multidisciplinary treatment for unresectable gastric cancer that attributed to peritoneal disseminations and direct invasion to other organs.Two courses of triplet chemotherapy(DCS therapy)were performed under enteral stent placement and nasoenteral nutrition for direct infiltration into the transverse colon with entire circumference stenosis.Distal gastrectomy and right hemicolectomy were performed as conversion therapy, and R0 resection was achieved.After the operation, S-1 as adjuvant chemotherapy was performed and there has been no relapse survival for 13 months since the operation.From this case, it seems that conversion therapy plays an important role in prognosis extension as a treatment strategy for Stage IV gastric cancer.

The technical outcomes of delta-shaped anastomosis in laparoscopic distal gastrectomy: a single-center safety and feasibility study.

BACKGROUND: The indications for laparoscopic gastrectomy for early stomach cancer have spread worldwide, and the short-term outcomes have been favorable. Intraabdominal delta-shaped gastroduodenostomy using endoscopic linear staplers, a technique which was developed by Kanaya et al. is one of the feasible reconstructive procedures. Pure laparoscopic surgery is reported to be associated with several intraoperative and postoperative advantages in comparison with laparoscopy-assisted surgery. However, the clinical results remain uncertain. The present study aimed to evaluate both the technical feasibility and safety of delta-shaped anastomosis with LDG according to the short-term outcomes. METHODS: The study group was composed of 229 patients who underwent delta-shaped anastomosis with LDG at Gifu University School of Medicine from December 2004 to December 2014. RESULTS: The median total operative blood loss and operative time were 20 ml and 277 min, respectively. Postoperative complications were detected in 20 (8.7 %) patients. The complications included: anastomotic stenosis, n = 3 (1.3 %); anastomotic leakage, n = 3 (1.3 %); pancreatic injury, n = 8 (3.5 %); anastomotic ulcer, n = 1 (0.4 %); bowel obstruction, n = 1 (0.4 %); abdominal abscess, n = 1 (0.4 %); lymphorrhea, n = 1 (0.4 %); cardiac failure, n = 1 (0.4 %); and infection, n = 1 (0.4 %). The complications were classified as grade 2, n = 4 (1.7 %); grade 3a, n = 12 (5.2 %); grade 3b, n = 4 (1.7 %); and grade 4 and 5, n = 0 (0 %). CONCLUSION: The findings of the present study indicate the safety of Kanaya's procedure and that it should provide better outcomes in patients who undergo intracorporeal gastroduodenostomy after laparoscopic distal gastrectomy.

[A Case Report of Neuroendocrine Carcinoma of the Esophagus Treated with Multidisciplinary Therapy].

A 72-year-old man was referred to our department because of esophageal tumor. Immunohistochemical findings were CD56-positive, synaptophysin-positive, chromogranin A-positive, Ki-67(labeling index)≥90%. The diagnosis was esophageal neuroendocrine carcinoma, categorized as cT4b(106recR-main bronchus), cN1(106recR), cM0, cStage III C. We had initiated irinotecan plus cisplatin(IP)as neoadjuvant chemotherapy(NAC). Biopsy specimens of primary lesion after 1 course chemotherapy showed a change to squamous cell carcinoma(SCC). The target lesion exhibited partial response(PR)after 2 courses of chemotherapy, and the primary lesion was reduced, but was still present. We performed subtotal esophagectomy and subtotal stomach reconstruction with lymphadenectomy(R0, Cur A). The histopathological findings showed the primary lesion was SCC, metastatic lymph nodes(106recR)was NEC. The final diagnosis was SCC plus NEC, categorized as CT-pT1a (MM), pN1(106recR), M0, fStage II B. After that, we selected treatment regimen considering tissue type, and performed surgery and chemotherapy for 2 times of recurrences. At a follow-up examination 1 year and 2 months after the start of first chemotherapy, the patient is alive without recurrence. Esophageal neuroendocrine carcinoma is relatively rare and the prognosis is poor, but there is as yet no standard therapy. We experienced a case of neuroendocrine carcinoma of the esophagus treated with multidisciplinary therapy.

Combination therapy with zoledronic acid and cetuximab effectively suppresses growth of colorectal cancer cells regardless of KRAS status.

Targeted molecular therapy is an effective anticancer strategy. Anti-EGFR monoclonal antibodies such as cetuximab (CTX) have been approved for the treatment of various malignancies, including colorectal cancer (CRC) with wild-type KRAS. However, their efficacy in patients with KRAS mutations has not been established. Therefore, we investigated whether CTX treatment was effective as a single agent or in combination with zoledronic acid (ZOL) in human CRC cell lines with different KRAS status. CRC cell lines SW48 (wild-type KRAS) and LS174T (mutant KRAS) were treated with ZOL, CTX and a combination of both drugs. Cytotoxicity was measured using the MTT assay. Changes in the levels of intracellular signaling proteins were evaluated using western blot analysis. Finally, we evaluated the efficacy of the combination treatment in an in vivo xenograft model. We observed that ZOL apparently inhibited growth in both cell lines, whereas CTX showed little effect. ZOL also increased the levels of unprenylated RAS. Combined ZOL and CTX treatment was synergistic in both cell lines and was associated with inhibition of the RAS-MAPK and AKT-mTOR signaling pathways. Furthermore, the combination treatment was more effective in suppressing the growth of xenografts derived from both SW48 and LS174T cells; this effect was associated with increased apoptosis. These results demonstrate that ZOL inhibits the growth of colon cancer cells regardless of KRAS status, and combination therapy using ZOL and CTX enhances this growth suppression. These findings suggest a novel strategy for the treatment of CRC independent of KRAS mutational status.

Phase II trial of neoadjuvant chemotherapy with docetaxel, nedaplatin, and S1 for advanced esophageal squamous cell carcinoma.

Although standard chemotherapy for esophageal cancer patients is fluorouracil and cisplatin, the prognosis is still unsatisfactory. A new therapeutic regimen combining docetaxel, cisplatin, and 5-fluorouracil was recently developed to improve both local and distant tumor control. We developed a new regimen of docetaxel, nedaplatin, and S1 (DGS) and previously reported the recommended dose in a phase I dose-escalation study. We then undertook a phase II study of DGS for advanced esophageal squamous cell carcinoma. Patients with clinical stage IB/II/III disease were eligible. Patients received two courses of chemotherapy: docetaxel 35 mg/m(2) with nedaplatin 40 mg/m(2) on day 8, 80 mg/m(2) S1 on days 1-14, and 2 weeks off. After completion of chemotherapy, patients underwent esophagectomy. The primary endpoint was the completion rate of protocol treatment (completion of two courses of preoperative chemotherapy and R0 surgery [no residual tumor]). We enrolled 32 patients. The completion rate of protocol treatment was 96.9%. During chemotherapy, the most common grade 3 or 4 toxicity was neutropenia (25.0%). No treatment-related deaths were observed, and the incidence of operative morbidity was tolerable. The overall response rate after chemotherapy was 83.3%. This DGS regimen was well tolerated and highly active. This trial is registered with the University Hospital Medical Information Network (UMIN ID: 000014626).

Is conversion therapy possible in stage IV gastric cancer: the proposal of new biological categories of classification.

Conversion therapy for gastric cancer (GC) has been the subject of much recent attention. It is defined as a surgical treatment aiming at an R0 resection after chemotherapy for tumors that were originally unresectable or marginally resectable for technical and/or oncological reasons. However, the indications for resection remain to be clarified. In the present review, we focus on the biology and heterogeneous characteristics of stage IV GC and propose new categories of classification. Stage IV GC patients can be divided based on the absence (categories 1 and 2) or presence (categories 3 and 4) of macroscopically detectable peritoneal dissemination, which has a different biological outcome compared to hematological metastasis. Category 1 is defined oncologically as stage IV but the metastasis is technically resectable. Category 2 includes a marginally resectable metastasis or patients for whom the operation would not necessarily be the best choice. Category 3 includes a potentially unresectable metastasis of peritoneal dissemination that is only macroscopically detectable. Category 4 includes noncurable metastasis with peritoneal and other organ metastasis. The indications for conversion therapy might include the patients from category 2, some patients from category 3 and a very small number of patients from category 4. The longer survival can be expected for patients corresponding to categories 1, 2 and, to a lesser extent, 3, while the treatment of other patients focuses on "care." The provision of conversion therapy for stage IV GC patients might be one of the main roles of surgical oncologists in the near future.

A case report on efficacy of Abound™ for anti-EGFR antibody-associated skin disorder in metastatic colon cancer.

BACKGROUND: Panitumumab is a full human epidermal growth factor receptor (EGFR) monoclonal antibody, an agent for metastatic colorectal cancer therapy. One of the most general adverse events of anti-EGFR monoclonal antibody therapy is skin disorder. At the present time, although prophylaxis of skin disorder is important for continuation of cancer therapy, there are no effective precautionary treatments. CASE PRESENTATION: A 73-year-old male with sigmoid colon cancer and synchronous lung metastasis was treated with panitumumab, an alone anti-EGFR monoclonal antibody as the third-line therapy.During the nine courses of the therapy, the response was stable disease (SD), but skin disorder gradually appeared obviously (CTCAE version 4.0: Grade 2). After 1 month of administration of Abound™, symptoms of the skin disorder improved (CTCAE version 4.0: Grade 1), thus the antibody therapy could be continued. CONCLUSION: We report that Abound™ was apparently effective in the treatment for anti-EGFR antibody-associated skin disorder. In the future, Abound™ could be expected as an agent for skin disorder as one of the side effects of colorectal cancer therapy.

Decreased FANCJ caused by 5FU contributes to the increased sensitivity to oxaliplatin in gastric cancer cells.

BACKGROUND: Oxaliplatin is effective against many types of cancer, and the combination of 5-fluorouracil (5FU) and oxaliplatin is synergistically effective against gastric cancer, as well as colon cancer. The FANCJ protein is one of the Fanconi anemia (FA) gene products, and its interaction with the tumor suppressor BRCA1 is required for DNA double-strand break (DSB) repair. FANCJ also functions in interstrand crosslinks (ICLs) repair by linking to mismatch repair protein complex MLH1-PMS2 (MutLα). While oxaliplatin causes ICLs, 5FU is considered to cause DSBs. Therefore, we investigated the importance of FANCJ in the synergistic effects of oxaliplatin and 5FU in MKN45 gastric cancer cells and the derived 5FU-resistant cell line, MKN45/F2R. METHODS: MKN1, TMK1, MKN45, and MKN45/F2R (5FU-resistant) gastric cancer cells were treated with 5FU and/or oxaliplatin. The signaling pathway was evaluated by a western blotting analysis and reverse transcription polymerase chain reaction (RT-PCR). Drug resistance was evaluated by the 3-(4,5-dimethyl-2-tetrazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay. RESULTS: In MKN45 cells, the combination of 5FU and oxaliplatin had synergistic effects. DSBs appeared when the cells were treated with 5FU. FANCJ was down-regulated, and BRCA1 was induced in a dose- and time-dependent manner. MKN45 cells showed increased sensitivity to oxaliplatin when FANCJ was knocked down by short interfering (si) RNA. However, these findings were not observed in MKN45/F2R 5FU-resistant cells. CONCLUSION: These results strongly suggest that the decrease in FANCJ caused by 5FU treatment leads to an increase in sensitivity to oxaliplatin, thus indicating that the FANCJ protein plays an important role in the synergism of the combination of 5FU and oxaliplatin.

Laparoscopic technique and safety experience with barbed suture closure for pelvic cavity after abdominoperineal resection.

BACKGROUND: Between April 2005 and December 2012, we performed laparoscopic colorectal resection with regional lymph node dissection on 273 cases of colorectal cancer patients. However, Laparoscopic rectal cancer surgery requires a high degree of skill. Any surgeon who is going to embark on these difficult resections should have at a minimum laparoscopic suturing skills in order to be able to close the peritoneal defect. METHODS: In laparoscopic surgery for rectal cancer, the intracorporeal suture technique required to close the pelvic cavity is very difficult. Barbed sutures have recently been proposed to facilitate laparoscopic suturing. Two patients with rectal cancer who underwent laparoscopic abdominoperineal resection (APR) with intracorporeal closure of the pelvic cavity from September to October 2012 were enrolled in this study. RESULTS: We present our initial experience of two consecutive cases of intracorporeal closure of the pelvic cavity by totally laparoscopic APR. After clinical follow-up, the two patients have no complaints and have shown no signs of recurrence. CONCLUSIONS: We hypothesized that barbed sutures could potentially improve the efficiency of intracorporeal closure of the pelvic cavity after laparoscopic APR. Further, we expect that use of the V-Loc™ will reduce intra-operative stress on the endoscopic surgeon.

Retrospective evaluation of the clinical necessity of external biliary drainage after pancreaticoduodenectomy.

BACKGROUND/AIMS: To evaluate the efficacy of internal biliary drainage after pancreaticoduodenectomy (PD), postoperative gastrointestinal function and complications of PD were compared in patients with and without the use of an external drainage stent for hepaticojejunostomy (HJ). METHODOLOGY: Between June 2005 and September 2011, 66 patients who underwent PD, including 40 patients with externally-stented HJ (ES group) and 26 patients with non-stented HJ (NS group), were included in this study, and postoperative bowel movements, oral intake, and complications were assessed. RESULTS: Time to tolerance of water or solid food were comparable between the two groups, and time to first bowel movement was significantly shorter in the NS group than in the ES group (3.2 +/- 1.6 days versus 4.6 +/- 1.7 days; p = 0.002). There were no differences in the incidence and severity of postoperative complications when comparing the two groups, whereas the incidence of postoperative cholangitis was significantly higher in the ES group (25.0%) than in the NS group (3.8%; p = 0.024). CONCLUSIONS: External biliary drainage may have a negative impact on biliary complications after PD, especially on the incidence of postoperative cholangitis.