Published papers

Human induced pluripotent stem cells (hiPSCs) are a promising cell source for elucidating disease pathology and therapy. The mass supply of hiPSC-derived cells is technically feasible. Carriers that can contain a large number of hiPSC-derived cells and evaluate their functions in vivo-like environments will become increasingly important for understanding disease pathogenesis or treating end-stage organ failure. hiPSC-derived hepatocyte-like cells (hiPSC-HLCs; 5 × 108) were seeded into decellularized organ-derived scaffolds under circumfusion culture. The scaffolds were implanted into immunodeficient microminiature pigs to examine their applicability in vivo. The seeded hiPSC-HLCs demonstrated increased albumin secretion and up-regulated cytochrome P450 activities compared with those in standard two-dimensional culture conditions. Moreover, they showed long-term survival accompanied by neovascularization in vivo. The decellularized organ-derived scaffold is a promising carrier for hiPSC-derived cells for ex vivo and in vivo use and is an essential platform for regenerative medicine and research.

[Case 1] A 54-year-old female presented with severe liver damage. During diagnosis, contrast-enhanced CT enhanced the area of hypoattenuation on unenhanced CT in the arterial phase, after which the enhanced effect was prolonged to the equilibrium phase. Then, we started immunosuppressive therapy based on the results, including corticosteroid administration, and her hepatitis subsided. [Case 2] A 57-year-old female also presented with severe hepatitis. Contrast-enhanced CT findings were similar to those of Case 1. Since hepatic encephalo-pathy developed and worsened to degree IV, a brain-dead liver transplant was conducted on the 21st day. Nev-ertheless, histological diagnosis was challenging in both cases. Therefore, when unenhanced CT shows hetero-geneous hypoattenuation in the liver and contrast-enhanced CT shows a characteristic blood flow disorder, acute-onset autoimmune hepatitis and corticosteroid treatment should be considered, including in complex se-rological or histological case diagnoses.

Background: Outflow control is difficult, and techniques required for effectively handling intraoperative hemorrhage during laparoscopic hepatectomy have not previously been adequately reported. Methods: Sixteen patients underwent surgery, of which 15 underwent laparoscopic left hepatectomy and one underwent laparoscopic partial hepatectomy of the caudate lobe. Encircling and taping of the common trunk of the middle (MHV) and left hepatic veins (LHV) was performed in 12 patients, and that of the LHV alone in four patients. Surgical techniques based on anatomical landmarks and histological findings are presented with videos. Histological confirmation of the anatomical landmarks for these procedures was performed in fresh cadavers to understand the anatomical structures and layers involved. Results: The median procedure duration was 15 (6-25) minutes. All procedures were performed safely with no major bleeding. Histological findings showed fibrous connective tissue between the tunica adventitia of the inferior vena cava (IVC) and the Laennec’s capsule of the liver. The layer of dissection was along the tunica adventitia of the IVC. Conclusions: The surgical techniques for encircling and taping of the common trunk of the MHV and LHV and the LHV alone based on anatomical landmarks were feasible and could allow for efficient outflow control in laparoscopic hepatectomy.

BACKGROUND Evidence has been published on the successful applications of the anti-tumor necrosis factor alpha antibody infliximab, such as induction therapy, salvage treatment for acute cellular rejection, and treatment for chronic ulcerative inflammation, in intestinal transplant recipients. However, the optimal protocol for the effective use of infliximab remains largely undetermined due to scarcity of available clinical data. We report a continuative application of infliximab as maintenance therapy for recurrent chronic ulcerative ileitis in a recipient of isolated intestinal transplantation (ITx). CASE SUMMARY The patient was a 11-year-old boy with intestinal motility disorder classified as a hypogenic type of intestinal dysganglionosis. The patient underwent living-donor related intestinal transplant. His immunosuppression regimen consisted of daclizumab, tacrolimus, and steroids. Although he did not show rejection while on tacrolimus monotherapy, routine screening endoscopy showed several ulcerative lesions in the distal end of the graft 2 years after the intestinal transplant. Endoscopic work up to evaluate the progression of anemia revealed stenosis with ulcerative inflammatory changes and multiple longitudinal ulcers in the graft. Since the endoscopic findings suggested ulcerative lesions in Crohn's disease, infliximab treatment was considered. Treatment with infliximab and a small dose of oral prednisolone afforded successful withdrawal of total parenteral nutrition and maintenance of a well-functioning graft without infectious complications for 5 years since the administration of the first dose of infliximab. CONCLUSION Infliximab is effective as maintenance therapy for recurrent chronic ulcerative ileitis in an isolated ITx patient.

Background: Approximately 8300 hemophiliacs are registered in Japan, but no comprehensive reports on hepatobiliary and pancreatic surgery (HBPS) have been conducted. This report investigates the current status of HPBS in hemophilia patients in Japan. Methods: The subjects were hemophiliac patients seen between January 1 2007, and December 31 2017, at facilities participating in this study among the facilities for performing high-difficulty cases nationwide designated by the Japanese Society for HBPS. A retrospective examination of short-term outcomes in 49 cases was conducted to assess patient background, disease, surgical procedure, and complications. Results: The types of hemophilia were A: 43 cases, B: four cases, and von Willebrand disease: two cases (hemophilia severity: mild 32, moderate seven, severe 10). The target malignant diseases for surgery were hepatocellular carcinoma (HCC) in 20 cases, intrahepatic cholangiocellular carcinoma (CCC) in four cases, combined HCC-CCC in two cases, hilar CCC in two cases, and pancreatic cancer in four cases. As for the surgical procedure, limited resection (subsegmentectomy and partial hepatectomy) was performed in 16 cases of HCC even with normal liver function tests. Pancreaticoduodenectomy and distal pacreatectomy were performed for pancreatic cancers as in the standard procedure. Postoperative complications were postoperative bleeding in two cases after hepatectomy and one after pancreatectomy in one case. When compared with Japanese National Clinical Data base, the complication rates after hepatectomy and pancreatectomy were not conspicuous in hemophilic patients. Conclusions: As long as they are performed in qualified centers, complication rate is not increased in hemophilic patients undergoing HBPS.

Background: The main causes of liver cirrhosis have changed over the past decade. In Japan, the number of deceased donors is increasing but is still insufficient relative to the number of patients awaiting a liver transplant. In the present study we aimed to assess the outcomes of candidates for liver transplantation. Methods: This was a retrospective study of adult patients who visited our department for consultation regarding liver transplantation from January 2009 to December 2020. Of a total of 601 patients, 336 were followed-up. The following data were collected and analyzed: patient's characteristics, liver etiology, Child-Pugh and MELD scores, and the eventual outcome, that is, whether liver transplantation was performed. Results: Only 153 of 336 (45.5%) patients underwent liver transplantation, of which 42 (27.5%) received deceased donor liver transplantation, and 129 (38.4%) died without transplantation. The proportion of patients who underwent liver transplantation was low among patients with nonalcoholic steatohepatitis (NASH) (10.7%) (P <.001). The rate of qualified living donors was the lowest for patients with NASH (28.6%) and that for the other etiologies ranged from 55.6% to 67.4% (P =.050). Conclusion: Patients with liver cirrhosis due to NASH may have a lesser chance of undergoing liver transplantation from both living and deceased donors.

Background: Living donor liver transplantation (LDLT) is the final treatment for children with end-stage liver disease. Congenital biliary atresia (CBA) is the most common disease requiring LDLT in Japan, and a left lateral sector graft is preferably procured owing to its anatomic predictivity and identical graft volume for preschool recipients. Laparoscopic left lateral sectionectomy (L-LLS) for LDLT has been recently established; however, there is no report about the innovative technique in L-LLS. The aim of this study was to introduce our L-LLS using the Glissonean approach and bridging technique for pediatric LDLT. Materials and Methods: From September 2017 to September 2020, 5 cases of L-LLS for pediatric LDLT because of CBA were performed and we performed L-LLS using the original technique on their donors. In this novel procedure, the left Glissonean pedicle was encircled at the parenchymal side of the Laennec capsule after mobilization of the lateral sector and visualization of the left hepatic vein. Then, we passed 2 tapes through the encircled Glissonean pedicle at the hepatic side and the duodenal side, as the caudate lobe branch is enclosed like a bridge. By virtue of this bridging technique, we encircled the caudate lobe branch alone by switching the tape, and we clipped and divided it; this technique secured an adequately long hepatic duct on the graft side to perform a hepaticojejunostomy. The left hepatic duct was divided after indocyanine green fluorescence cholangiography, and the left hepatic artery and portal vein were divided as well. Finally, the left hepatic vein was transected and procured from an extended intraumbilical incision. Results: We achieved L-LLS by using the Glissonean approach and the bridging technique in the 5 donors. The median operating time and blood loss were 282 (268 to 332) minutes and 34 (25 to 75) mL, respectively. There was no conversion to hybrid or open LLS and no postoperative complications. Regarding recipient outcomes, hepatic artery thrombosis occurred on postoperative day 4 in a 5-year-old female. All grafts function well and all recipients are alive after discharge (range of observation period, 3 to 26 mo). Conclusions: We herein present standardized L-LLS using the Glissonean approach and bridging technique for pediatric LDLT. Our technique can secure a longer margin of the left hepatic duct for recipients' hepaticojejunotomy. Our results have demonstrated the advantage in pediatric LDLT, especially in patients with CBA after the Kasai procedure.

Purpose: Laparoscopic left lateral sectionectomy (LLLS) is a feasible and safe procedure with a relatively smooth learning curve. However, single-incision LLLS requires extensive surgical experience and advanced techniques. The aim of this study is to report the standardized single-incision plus one-port LLLS (reduced port LLLS, RPLLLS) technique and evaluate its safety, feasibility, and effectiveness for junior surgeons. Methods: Between January 2008 and November 2020, the clinical records of 49 patients who underwent LLLS, divided into the conventional LLLS (n = 37) and the RPLLLS group (n = 12), were retrospectively reviewed. The patient characteristics, pathologic results, and operative outcomes were evaluated. Results: A history of previous abdominal surgery in the RPLLLS group was significantly high (56.8% vs. 91.7%, p = 0.552). Notably, junior surgeons performed 62.2% of the conventional LLLSs and 58.4% of the standardized RPLLLSs. There were no significant differences between the two groups in terms of median operative time (121.0 vs. 113.5, p = 0.387), median blood loss (13.0 vs. 8.5, p = 0.518), median length of hospital stays (7.0 vs. 7.0, p = 0.408), and morbidity rate (2.7% vs. 0%, p = 0.565), respectively. Conclusion: This standardized RPLLLS is a feasible and safe alternative to conventional LLLS and may become the ideal training procedure for both junior surgeons and surgeons aiming to learn more complex procedures.

A 58-year-old woman was admitted to hospital for deceased donor liver transplant. Her liver volume, measured by computed tomography, had reached 22,764 cm3 and she was bedridden with performance status 3 because of abdominal distention. The Model for End-Stage Liver Disease score was 24 with exception points. The final weight of the removed liver after cystic fluid puncture was 14 kg. The patient recovered well after transplant and was discharged on postoperative day 43 with a weight of 41 kg and performance status of 1.

Purpose: Acute liver failure is a life-threatening condition for which ABO-incompatible living donor liver transplantation (ABOi-LDLT) is sometimes the only life-saving treatment option. We reviewed a single-center experience of adult ABOi-LDLT treatment for acute liver failure (ALF). Methods: Preoperative treatment, immune indices (B cell marker, anti-donor blood-type antibody), and postoperative outcomes were compared between ALF and non-ALF groups. Results: There were 5 and 33 patients in the ALF and non-ALF groups, respectively. The ALF group received higher doses of steroids, underwent more rounds of plasma exchange (PE), and underwent transplantation for ALF with a shorter interval following preoperative rituximab (RTx) administration (median: 2 vs 13 days; P < 0.05) than the non-ALF group. Preoperatively, CD19-positive lymphocytes in the peripheral blood were sufficiently depleted in all of the non-ALF group patients, whereas they were poorly depleted in the ALF group. Postoperatively, neither group suffered anti-donor blood-type antibody titer rebound or antibody-mediated rejection. The ALF group had a comparable 5-year survival rate to the non-ALF group (80.0% vs 77.9%). Conclusions: Despite the delayed preoperative administration of RTx, the ALF group showed an uneventful immunological response and acceptable long-term survival rate. Thus, ABOi-LDLT seems a viable treatment option for ALF.

Purpose: Hepatic veno-occlusive disease (HVOD) after liver transplantation (LT) is almost always a fatal complication. We assessed the outcomes of HVOD in a single institute and analyzed a literature-based cohort. Methods: We reviewed the medical records of recipients of LT performed between 1995 and 2020 at our institute and the literature on HVOD after LT. We then analyzed the clinical features based on a “pooled” cohort of cases identified in our institute and reported in the literature. Results: HVOD was diagnosed in 3 of 331 LT recipients, all of whom died in hospital, on days 164, 12, and 13, respectively. Our comprehensive review of the literature, as well as our cases, identified eight cases of HVOD that developed within 14 days after LT (early-onset type). Early-onset HVOD had a significantly worse prognosis than HVOD that developed beyond 2 weeks after LT (non-early-onset type), which was identified in 22 cases (25.0% vs. 86.1% of the 3-month graft survival rate). The most common causes of early-onset and non-early-onset types were acute cellular rejection (50%) and drug-induced disease (50%), respectively. Conclusion: Early-onset HVOD developing within 14 days after LT has a poor prognosis.

Background/objectives: This study aimed to evaluate the safety, efficacy, and long-term outcomes of S-1-based neoadjuvant chemoradiotherapy (NACRT) in patients with resectable or borderline-resectable pancreatic ductal adenocarcinoma (PDAC). Methods: This retrospective study included patients with PDAC who underwent S-1-based NACRT at our institute between 2010 and 2017. Results: Forty patients were included in the study, including 15 (37.5%) with resectable PDAC and 25 (62.5%) with borderline-resectable PDAC. The NACRT completion and resection rates were 85.0% (n = 34) and 67.5% (n = 27), respectively. Several grade 3 adverse events were observed, including leukopenia (25.0%), anorexia (17.5%), neutropenia (10.0%), thrombocytopenia (7.5%), febrile neutropenia (2.5%), elevated aspartate aminotransferase/alanine aminotransferase (2.5%) levels, and hyponatremia (2.5%). The R0 resection rate was 70.4% (n = 19/27) in patients who underwent pancreatectomy. Grades 1, 2, and 3 according to the College of American Pathologists grading system were observed in 1 (3.7%), 12 (44.4%), and 14 (51.9%) patients, respectively. Over a median follow-up period of 32.9 months (interquartile range, 9.1–68.0), the 1-, 3-, and 5-year OS rates were 81.4%, 45.5%, and 30.3%, respectively, in the intention-to-treat analysis. In the curative-intent surgery cohort (n = 27), the 1-, 3-, and 5-year OS rates were 88.9%, 48.2%, and 37.0%, respectively. Conclusions: S-1-based NACRT is safe and yields acceptable long-term outcomes for patients with resectable or borderline-resectable PDAC.

The excess mortality of coronavirus disease 2019 (COVID-19) solid organ transplant recipients (SOTRs) throughout the pandemic remains unclear. This prospective cohort study based on the Japanese nationwide registry included 1632 SOTRs diagnosed with COVID-19 between February 1, 2020, and July 31, 2022, categorized based on dominant phases of variants of concern (VOCs): Waves 1 to 3 (Beta), 4 (Alpha), 5 (Delta), 6 (Omicron BA.1/BA.2), and 7 (Omicron BA.5). Excess mortality of COVID-19-affected SOTRs was analyzed by calculating standardized mortality ratios (SMRs). Overall, 1632 COVID-19-confirmed SOTRs included 1170 kidney, 408 liver, 25 lung, 20 heart, 1 small intestine, and 8 multiorgan recipients. Although disease severity and all-cause mortality decreased as VOCs transitioned, SMRs of SOTRs were consistently higher than those of the general population throughout the pandemic, showing a U-shaped gap that peaked toward the Omicron BA.5 phase; SMR (95% CI): 6.2 (3.1-12.5), 4.0 (1.5-10.6), 3.0 (1.3-6.7), 8.8 (5.3-14.5), and 21.9 (5.5-87.6) for Waves 1 to 3 (Beta), Wave 4 (Alpha), Wave 5 (Delta), Wave 6 (Omicron BA.1/2), and Wave 7 (Omicron BA.5), respectively. In conclusion, COVID-19 SOTRs had greater SMRs than the general population across the pandemic. Vaccine boosters, immunosuppression optimization, and other protective measures, particularly for older SOTRs, are paramount.

Background: In Japan, there has never been a national analysis of pediatric deceased donor liver transplantation (pDDLT) based on donor and recipient factors. We constructed a Japanese nationwide database and assessed outcomes of pDDLT focusing on the pediatric prioritization system introduced in 2018. Methods: We collected data on pDDLTs (<18 years) performed between 1999 and 2021 from the Japan Organ Transplant Network and Japanese Liver Transplantation Society, identified risk factors for graft survival and compared the characteristics and graft survival in pDDLTs conducted before and after the introduction of the pediatric prioritization system. Results: Overall, 112 cases of pDDLT were included, with a 1-year graft survival rate of 86.6%. Four poor prognostic factors were identified: recipient intensive care unit stay, model for end-stage liver disease/pediatric end-stage liver disease score, donor cause of death, and donor total bilirubin. After the introduction of the system, allografts from pediatric donors were more reliably allocated to pediatric recipients and the annual number of pDDLTs increased. The 1-year graft survival rate improved significantly as did pDDLT conditions indicated by the risk factors. Conclusions: Under the revised allocation system, opportunities for pDDLT increased, resulting in favorable recipient and donor conditions and improved survival.

Background: Validating the expanded criteria for living donor liver transplantation for hepatocellular carcinoma using national data is highly significant. The aim of this study was to evaluate the validity of the new Japanese criteria for living donor liver transplantation for hepatocellular carcinoma patients and identify factors associated with a poor prognosis using the Japanese national data set. Methods: The study population comprised patients who underwent living donor liver transplantation for hepatocellular carcinoma at 37 centres in Japan between 2010 and 2018. In a nationwide survey, the overall survival and recurrence-free survival rates were evaluated based on the new Japanese criteria for applying the 5-5-500 rule when extending the indication beyond the Milan criteria. Prognostic factors within the Japanese criteria were determined using the Cox proportional hazards model. Results: Patients within (485 patients) and beyond (31 patients) the Japanese criteria exhibited 5-year overall survival rates of 81% and 58% and 5-year recurrence-free survival rates of 77% and 48% respectively. Patients who met the Milan criteria, but not the 5-5-500 rule, had poorer outcomes. Multivariate analysis for 474 patients identified a neutrophil-to-lymphocyte ratio greater than or equal to 5 and a history of hepatectomy as independent risk factors. Conclusion: This nationwide survey confirms the validity of the Japanese criteria. The poor prognostic factors within the Japanese criteria include a neutrophil-to-lymphocyte ratio greater than or equal to 5 and previous hepatectomy.

Technique: Laparoscopic cholecystectomy (LC), widely performed for gallbladder (GB) diseases poses risks of severe complications. To minimize these risks, Tokyo Guidelines 2018 advocated for “safe steps in LC for acute cholecystitis (AC)” including “maintaining the plane of dissection on the GB surface throughout LC”. Moreover, the dissection along the inner layer of the subserosa (SS-inner) of GB helps surgeons avoid bile duct or vascular injury. This step occasionally becomes challenging when distinguishing the GB surface from adjacent fat. ICG, injected into biliary tract, illuminates in green under Infra-red (IR) mode and facilitates the identification of biliary tract. Otherwise, Yellow Enhance (YE) mode developed by Olympus Corporation, which highlights yellow-colored tissues by converting orange-yellow tissues to a clearer yellow, improves the contrast between anatomical structures. Results: In a case of AC following percutaneous transhepatic gallbladder drainage (PTGBD), we applied both ICG fluorescence and YE mode. The ICG injected from PTGBD illuminated the GB surface in green, while YE mode highlighted the fatty tissue in a clearer yellow, facilitating the distinction between these two tissues and the accurate dissection along the SS-inner. An additional advantage of injecting ICG from PTGBD, or from the cannulation tube intraoperatively inserted to GB, over intravenous administration is that the GB surface can be illuminated in cases of GB stone incarceration. Conclusion: The combination of ICG fluorescence and YE mode encourages surgeons to identify the boundary between the GB surface and the surrounding fatty tissues, which assists the accurate dissection along the SS-inner.

Introduction: Pure laparoscopy for living donor hepatectomy is gaining popularity due to its advantages. However, despite the long-standing application of laparoscopic donor left lateral sectionectomy, the dissection of the Glisson branch, portal vein, and biliary ducts, particularly those of the caudate lobe, remains insufficiently described. Although the Glissonean approach offers easy standardization for hilar dissection, clear landmarks for parenchymal transection, and reduces postoperative bile leakage, it has not been widely adopted in laparoscopic donor hepatectomy. Here, we introduce a modified Glissonean pedicle approach to address the movement restrictions in laparoscopic surgery. Surgical Technique: After liver mobilization, the Glisson of Spiegel lobe (G1L) was divided, followed by encircling the left Glissonean pedicle. A tape for the liver hanging maneuver was placed from the right edge of the left Glissonean pedicle, along the Arantius plate, to the left edge of the left hepatic vein. When the parenchymal transection was completed, the left hepatic vein was automatically taped. The left hepatic artery and left portal vein were exposed, and some branches of P1 were divided to lengthen for anastomosis. The left hepatic duct was taped by removing the left hepatic artery and left hepatic vein from the left Glissonean pedicle. The left hepatic duct was divided under intraoperative cholangiography. Next, the left hepatic artery, left portal vein, and left hepatic vein were sequentially divided, and the graft liver was retrieved. Discussion: Our Glissonean approach can help standardize donor left lateral sectionectomy, minimize the exposure of the left hepatic duct, and clarify B1 branch dissection.

Introduction: Pancreatic cancer (PC) is highly malignant and metastatic; however, bone metastases are rare. Although the effectiveness of conversion surgery for distant metastases of PC has been reported in a few cases, there are no reports on surgical resection for bone metastases. Here, we report a case of long-term survival after resection of bone metastasis from PC. Patient concerns: A 60-year-old woman underwent pancreaticoduodenectomy after neoadjuvant chemoradiotherapy for pancreatic head cancer. At 28 months after surgery, multiple lung metastases from PC were diagnosed, and chemotherapy was administered. After 59 months, chemotherapy was terminated because all target lesions had disappeared on imaging. Diagnosis: At 77 months after the initial surgery, bone metastasis in the left 9thrib was detected by positron emission tomography/computed tomography, which was performed due to elevated carbohydrate antigen 19-9 levels. Interventions: Chemotherapy was readministered as the initial treatment. Subsequently, due to the long-term well-controlled status of the recurrence site and the absence of other metastases, thoracoscopic-assisted partial resection of the left 9thrib was performed 128 months following pancreaticoduodenectomy. Pathological examination revealed adenocarcinoma metastasis from PC. Outcomes: The patient is currently alive without recurrence 44 months after resection for bone metastasis and 172 months after the initial surgery. Conclusion: Surgical resection may be favorable in patients with bone metastasis of PC that is well-controlled with chemotherapy.

Here, we describe a rare case of malignant lymphoma after liver transplantation for liver cirrhosis caused by human immunodeficiency virus (HIV) and hepatitis C virus (HCV) co-infection. A male patient was diagnosed with hemophilia A at 8 months of age. Since then, he had been receiving blood products, which led to HIV and HCV co‐infection. His HIV viral load was suppressed with antiretroviral therapy, and a sustained virologic response was achieved for HCV using direct-acting antivirals. However, his decompensated liver cirrhosis progressed, and deceased donor liver transplantation was performed. A post-transplant lymphoproliferative disorder (PTLD) developed 105 days after liver transplantation, with enlarged para-aortic and hilar lymph nodes, a right renal mass, and masses in the small and large intestines. Histopathological examination confirmed monomorphic PTLD (diffuse large B-cell lymphoma). Against the treatment (reduction of immunosuppression, rituximab, and chemotherapy), the response was poor, and the patient died 94 days after the outbreak of PTLD. Both transplantation and HIV infection are risk factors for lymphoproliferative diseases. To the best of our knowledge, this is one of the very few reports of PTLD in a patient with HIV/HCV co-infection.

Positive peritoneal washing cytology is an indicator of poor prognosis in patients with pancreatic ductal adenocarcinoma (PDAC); however, its sensitivity is relatively low. This study evaluated the performance of peptide nucleic acid (PNA)-directed PCR clamping as a molecular-based peritoneal washing cytology for sensitive detection of KRAS mutation in PDAC. Intraoperative peritoneal washing fluid (IPWF) obtained from patients with PDAC who underwent surgery was analyzed. PNA-directed PCR clamping was performed on DNA extracted from IPWF. Among 54 patients enrolled, threshold cycle (Ct) was significantly lower in patients with positive peritoneal washing cytology than in those with negative peritoneal washing cytology (P < 0.001) and in patients with peritoneal dissemination than in those without peritoneal dissemination (P < 0.01). The optimal Ct cut-off to predict KRAS mutations in IPWF was 36.42 based on a receiver operating characteristic curve. The sensitivity, specificity, and accuracy for molecular diagnosis were 100%, 80.0%, and 85.2%, respectively. Peritoneal dissemination recurrence was significantly more frequent in patients with a positive molecular diagnosis than in those with a negative diagnosis (38.9 vs. 8.0%, P = 0.013). The genomic approach might be clinically valuable for a more precise tumor cell detection in IPWF.