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Pancreatic cancer has an extremely poor prognosis, even after curative resection. Treatment options for pancreatic cancer remain limited, therefore new therapeutic targets are urgently needed. We searched for genes predictive of poor prognosis in pancreatic cancer using a public database and validated the survival impact of the selected gene in a patient cohort. We used a public database to search for genes associated with early pancreatic cancer recurrence. As a validation cohort, 201 patients who underwent radical resection in our institution were enrolled. Expression of the target gene was evaluated using immunohistochemistry (IHC). We evaluated growth and invasiveness using small interfering RNAs, then performed pathway analysis using gene set enrichment analysis. We extracted ARHGEF2 from GSE21501 as a gene with a high hazard ratio (HR) for early recurrence within 1 year. The high ARHGEF2 expression group had significantly poorer recurrence-free survival (RFS) and poorer overall survival (OS) than the low ARHGEF2 expression group. Multivariate analysis demonstrated that high ARHGEF2 expression was an independent poor prognostic factor for RFS (HR 1.92) and OS (HR 1.63). In vitro, ARHGEF2 suppression resulted in reduced cell growth and invasiveness. Bioinformatic analysis revealed that ARHGEF2 expression was associated with MYC, G2M, E2F, and CDC25A expression, suggesting that c-Myc and cell cycle genes are associated with high ARHGEF2 expression. IHC revealed a positive correlation between ARHGEF2 and c-Myc expression. High ARHGEF2 expression is associated with cell cycle progression, and predicts early recurrence and poor survival in patients with pancreatic cancer.

Background The predictive significance of programmed death ligand 1 (PD-L1) for programmed death 1 (PD-1) inhibitors remains unclear in gastric cancer (GC) due to the dynamic alteration by treatments. We aimed to elucidate the effects of trastuzumab (Tmab) on PD-L1 expression in GC. Methods PD-L1 expression was evaluated by multicolour flow cytometry analysis after co-culturing GG cell lines and immune cells with Tmab. IFN-γ in the co-culture experiments was quantified. Immunohistochemistry (IHC) for PD-L1 expression using clinical samples was also performed to confirm PD-L1 alteration by Tmab. Results PD-L1 expression was significantly upregulated by Tmab in HER2-amplified GC cell lines co-cultured with peripheral blood mononuclear cells (PBMCs). PD-L1 upregulation by Tmab was also observed in the GC cells co-cultured with NK cells in time-dependent manner, but not with monocytes. IFN-γ concentration in conditioned media from co-cultured PBMCs and NK cells with Tmab was significantly higher and anti-IFN-γ significantly suppress the Tmab-induced PD-L1 upregulation. IHC also suggested PD-L1 upregulation after Tmab treatment. Conclusions Tmab can upregulate PD-L1 expression on GC cells through interaction with NK cells. These results suggest clinical implications in the assessment of the predictive significance of PD-L1 expression for PD-1 inhibitors.

Background An accurate diagnosis of the primary cancer or metastatic tumor is quite important because misdiagnosis may lead to the selection of incorrect adjuvant therapy and worse long-term outcomes after surgery. Here, we present a rare case with an unusual metastatic pattern mimicking a hilar cholangiocarcinoma originated from colon cancer Case presentation A 69-year-old man was referred to our hospital because of an upper bile duct stenosis. He had the past history of the sigmoidectomy for the primary colon cancer and the partial hepatectomy with radiofrequency ablation (RFA) for synchronous liver metastases 4 years ago. After 2 years from the initial operation, he had experienced the local recurrence of post-RFA lesion and had undergone a partial hepatectomy. According to the radiological findings of the bile duct stenosis, we diagnosed a hilar cholangiocarcinoma (Bismuth type II), and then he underwent the extended right hepatectomy with extrahepatic bile duct resection. Histological findings including the immune-histochemical examinations (CK7−, CK20+, CDX2+ and SATB2+) uncovered the metastatic tumor into extrahepatic bile duct originated from the primary colon cancer. Conclusion We experienced an extremely rare case with a colon cancer metastasis mimicking a hilar cholangiocarcinoma. In this case with a past history of colon cancer, an immunohistochemical staining led us to distinguish the primary hilar cholangiocarcinoma and the mimicking tumor.

The prediction of prognostic outcomes can provide the most suitable strategy for patients with pancreatic ductal adenocarcinoma (PDAC). This study aimed to evaluate the clinical value of the preoperative tumor marker index (pre-TI) in predicting prognostic outcomes after resection for PDAC. For 183 patients who underwent pancreatic resection of PDAC, adjusted carbohydrate antigen 19-9 (CA19-9), carcinoembryonic antigen (CEA), pancreatic cancer-associated antigen-2 (DUpan-2), and s-pancreas-1 antigen (SPan-1) were retrospectively evaluated, and the positive number of these markers was scored as the pre-TI. A high pre-TI (≥ 2) was significantly associated with a larger tumor and lymph node metastases, and the patients with a high pre-TI had worse prognostic outcomes in terms of both relapse-free survival (RFS) (P

Preoperative biliary drainage (PBD) prior to pancreatoduodenectomy (PD) is controversial. The aim of this study was to clarify how PBD leads to postoperative complications of PD. The subjects of this retrospective study were 230 patients who underwent PD between January, 2008 and January, 2018. We analyzed how PBD was associated with severe postoperative complications (Clavien-Dindo ≥ IIIB) with special reference to its links with bacterial contamination. Preoperative biliary drainage (PBD) was correlated with the contamination of both bile juice collected at surgery (p

Programmed death ligand 1 (PD-L1) is a key target for the treatment of several malignancies. The present study was conducted to clarify the role of serum PD-L1 in hepatocellular carcinoma (HCC). Serum PD-L1 (sPD-L1) was examined by an enzyme-linked immunosorbent assay in 153 patients with HCC who underwent curative hepatectomy at Kumamoto University in 2011–2016. The expression of PD-L1 in tissue (tPD-L1) was investigated by immunohistochemistry. The clinical roles of the PD-L1 expression in both serum and tissue were examined. The sPD-L1 was significantly elevated in HCC patients compared to patients without any malignant or inflammatory disease (234 vs. 93 pg/mL, p

INTRODUCTION The aim of this study was to evaluate the safety and efficacy of interval laparoscopic appendectomy after antibiotic therapy in elderly patients with appendiceal abscess. METHODS We retrospectively analyzed data for 50 patients with appendiceal abscess aged ≥18 years who had initially planned to undergo interval laparoscopic appendectomy after antibiotic therapy and 50 patients with appendicitis aged ≥70 years who had undergone early laparoscopic appendectomy. All patients were treated at the National Hospital Organization Kumamoto Medical Center between 2012 and 2018. We compared perioperative outcomes after interval appendectomy between patients aged

Whether perioperative allogeneic blood transfusion (PABT) negatively influences patient survival after hepatectomy (HR) for hepatocellular carcinoma (HCC) remains controversial. Five hundred two patients who underwent HR for initial HCC between 1994 and 2015 were enrolled in this study. All patients were divided into two groups: the PABT group and the non-PABT group. Differences of clinicopathological factors, overall survival (OS), recurrence-free survival (RFS), and the recurrence pattern between the two groups were evaluated. Using propensity score matching for tumor-related factors, liver functions, and surgical factors (total 11 factors), the survival impact of PABT was also analyzed. In the entire cohort, 78 patients (15.5%) received PABT such as red cell concentrate, fresh-frozen plasma, or platelets. OS (5-year OS: 55% vs. 76%; p = 0.0005) and RFS (2-year RFS: 47% vs. 56%; p = 0.0131) were significantly worse in the PABT group. The extrahepatic recurrence happened more frequently in the PABT group (15% vs. 5.4%; p = 0.0039). There were many significant clinicopathological differences between the two groups: more advanced tumor stage (tumor diameter, stage III or IV, microvascular invasion), worse liver functions (albumin, indocyanine green retention rate at 15 min), and more surgical stress (blood loss, operation time) in the PABT group. After propensity score matching, 43 pairs of patients were extracted. In this matched cohort, the survival curves of the PABT and non-PABT groups almost completely overlapped both in OS (5-year OS: 62% vs. 62%; p = 0.4384) and in RFS (2-year RFS: 49% vs. 47%; p = 0.8195). The significant difference of the extrahepatic recurrence rate disappeared in the matched cohort (p = 0.5789). Using propensity score matching, we found that PABT does not influence patient survival after HR for HCC.

Background/aim Identifying malignancy in intraductal papillary mucinous neoplasm (IPMN) of the pancreas remains challenging. This study aimed to evaluate the usefulness of 18-fluorodeoxyglucose positron emission tomography/computed tomography (18-FDG PET/CT) in distinguishing malignant from benign IPMN of the pancreas. Patients and methods The cases of 79 patients with IPMN of the pancreas who underwent surgical resections between 1996 and 2016 at our Institution were enrolled in the present retrospective analysis of predictors for malignancy in IPMN of the pancreas. 18-FDG PET/CT evaluations were performed in 38 patients, and the usefulness of 18-FDG PET/CT for detecting malignancy in IPMN of the pancreas was evaluated. Results Three factors were significantly related to malignancy in IPMN; the diameter of the main pancreatic duct, the serum value of carcinoembryonic antigen (CEA), and the neutrophil-to-lymphocyte ratio (NLR). 18-FDG PET accumulation was significantly related to malignancy in IPMN; sensitivity 0.82 and specificity 0.71. Independent predictors for malignancy in IPMN were as follows: 18-FDG PET accumulation, CEA >1.0 ng/ml, and NLR >2.63. Conclusion 18-FDG PET accumulation is a potent new marker for distinguishing malignant from benign IPMNs of the pancreas.

Background Hepatic inflammatory pseudotumor (IPT) is a rare, benign, tumor-like lesion. Because there are no characteristic laboratory markers or radiological features, hepatic IPT is often misdiagnosed as a malignant neoplasm such as hepatocellular carcinoma (HCC). Case presentation A 68-year-old man with liver dysfunction due to chronic hepatitis C virus infection and alcoholic liver disease presented with hepatic tumors in segments III and VIII. The levels of serum alpha-fetoprotein (AFP) and its Lens culinaris agglutinin-reactive fraction, AFP lectin 3 (AFP-L3), were elevated to 822.8 ng/ml and 75.2%, respectively. The tumor showed contrast enhancement on contrast-enhanced computed tomography and various accumulation on positron emission tomography. Based on these biological and imaging features, HCC was suspected, and we performed laparoscopic partial hepatectomy for these two tumors. Pathological diagnosis revealed that both tumors were hepatic IPTs with no malignant characteristics. After hepatectomy, the serum AFP and AFP-L3 levels decreased to the normal range. Conclusion We report a very rare case of hepatic IPT with elevated serum AFP and AFP-L3, mimicking HCC. Clinicians should include this rare neoplasm in the differential diagnoses of hepatic tumors even when the serum markers for HCC are elevated.

Background Postoperative complications after pancreaticoduodenectomy (PD) is still a major concern. The aim of this study was to propose how to choose antibiotics, based on bacterial sensitivity profiling involved in postoperative complications after PD. Methods Two hundred and thirty patients underwent PD between 2008 and 2018 at Kumamoto University Hospital. We enrolled 121 patients who had both intraoperative bile culture and drain culture on postoperative day (POD) 3. The clinical impact of the bacterial profile on postoperative outcome was retrospectively analyzed. Results Multivariate regression analysis revealed that intraperitoneal contamination on POD3 was independently associated with postoperative complications (odds ratio 2.62, P =0.02). The bacteria in intraperitoneal drain on POD3 showed 94.9% similarity with those in bile collected during surgery. The major species were Enterococcus (44.6%) and Enterobacter (38.5%). Enterobacter species caused a higher rate of postoperative complications than others (83% vs 54%, P =0.04). Three out of five Enterococcus faecium were resistant to carbapenems that were active against all Gram-negative rods. Conclusions Intraperitoneal contamination on POD3, which had similar bacterial species as bile collected during surgery, was correlated with postoperative complications. The bacterial antibiotic sensitivity profile may help selecting optimal antibiotics against infectious postoperative complications in PD.

MicroRNA (miRNA) expression abnormalities are implicated in tumor progression. Previous reports have indicated that microRNA-25 (miR-25) acts as a tumor suppressor or oncogene in diverse cancers. However, its molecular mechanisms in hepatocellular carcinoma (HCC) are still unclear. F-box and WD repeat domain 7 (Fbxw7) is a critical tumor suppressor and is one of the most important deregulated proteins of the ubiquitin–proteasome system in cancer. Our objective was to elucidate the role of miR-25 and Fbxw7 in HCC and to clarify the mechanism by which Fbxw7 is regulated. Fbxw7 expression was estimated in 210 fixed paraffin-embedded HCC samples by immunohistochemistry, and miR-25 expression was evaluated in 142 frozen HCC tissue samples by quantitative real-time PCR. Oncogenic functions of miR-25 and its role in the regulation of Fbxw7 expression were assayed in vitro. miR-25 was overexpressed in HCC tissue compared with adjacent normal tissue and significantly correlated with a poorer prognosis. Moreover, it was inversely correlated with Fbxw7 expression in HCC tissues. Furthermore, miR-25 inhibition significantly reduced the proliferation, migration, and invasion of HCC cells in vitro. miR-25 may promote tumor progression in HCC patients by repression of Fbxw7 and could serve as a promising molecular target for HCC treatment.

Highlights • Neuroendocrine carcinoma of the esophagus is a rare and highly aggressive disease. • A case of large-cell neuroendocrine carcinoma of the esophagus in a 73-year-old male patient with aggressive surgical treatment. • We performed subtotal esophagectomy, partial hepatectomy, radiotherapy and chemotherapy using cisplatin and irinotecan. • We believe that aggressive treatment can become one treatment option with the aim of extending survival., Introduction Neuroendocrine carcinoma of the esophagus is a rare and highly aggressive disease, and the biological features are poorly understood. Presentation of case We report a case of large-cell neuroendocrine carcinoma of the esophagus in a 73-year-old male patient with aggressive surgical treatment. Upper gastrointestinal endoscopy revealed an esophageal large mass. Histological examination of biopsy specimens indicated a neuroendocrine carcinoma. First, we performed subtotal esophagectomy with lymphadenectomy, but he experienced metastasis at the liver and rib 5 months later. Next, we performed partial hepatectomy and radiotherapy for rib metastasis, but he experienced metastasis at the left pulmonary hilar lymph node and sacral bone. Finally, we performed chemotherapy using cisplatin and irinotecan. Discussion The therapeutic strategy for large-cell NEC of the esophagus is unestablished. Thus, accumulating the therapeutic results garnered from various treatment tools is considerably important. Conclusion Aggressive multimodal treatments including surgery have a possibility to gain better survival in patients with large-cell NEC of the esophagus.

Portal vein embolization (PVE) was developed for patients with insufficient future liver remnant volume and function and has gained relevant support worldwide before major hepatectomy. However, the efficacy of preoperative PVE for hepatocellular carcinoma (HCC) patients with impaired liver function remains uncertain. Ninety-seven HCC patients who were scheduled for PVE followed by hepatectomy were enrolled in this study. Their short- and long-term outcomes were investigated, according to the liver damage classification defined by the Liver Cancer Study Group of Japan. Of 97 patients who underwent preoperative PVE, 30 (32.4%) could not undergo subsequent hepatectomy. Dropout rate from treatment strategy was significantly higher in patients with liver damage B (n = 13, 61.5%) than in those with liver damage A (n = 84, 26.2%) (P = 0.014). Among the 67 patients who underwent planned hepatectomy after PVE, 53 were categorized to liver damage A, and 14 were categorized to liver damage B at the point of hepatectomy. Although major complication and mortality rates were comparable between the two groups, the cumulative overall survival (OS) and disease-free survival (DFS) after hepatectomy were markedly worse in patients with liver damage B than in those with liver damage A (5-year OS rate: 23.1% vs 74.6%, P = 0.014, 5-year DFS rate: 7.8% vs 33.5%, P = 0.054, respectively). The treatment strategy of PVE followed by hepatectomy might be a contraindication for HCC patients with impaired liver function categorized as liver damage B because of the higher dropout rate and poorer long-term outcomes after hepatectomy.

Aim Combined hepatocellular cholangiocarcinoma (cHCC-CCA) is a very rare subtype of primary liver carcinoma; therefore, its clinicopathological characteristics have not yet been elucidated in detail. The aim of the study was to reveal the clinicopathological characteristics and prognostic factors of cHCC-CCA after hepatic resection (HR) METHODS: A total of 124 patients who underwent curative HR for cHCC-CCA between 2000 and 2016 were enrolled in this multi-institutional study conducted by the Kyushu Study Group of Liver Surgery. Clinicopathological analysis was performed from the viewpoint of patient prognosis. Results A total of 62 patients (50%) had early recurrence within 1.5 years after HR, including 36 patients (58%) with extrahepatic recurrence. In contrast, just four patients (3%) had late recurrence occurring >3 years after HR. The independent predictors of early recurrence were as follows: des-gamma carboxyprothrombin >40 mAU/mL (odds ratio 26.2, P = 0.0117), carbohydrate antigen 19-9>37 IU/l (odds ratio 18.0, P = 0.0200), and poorly differentiated HCC or CCA (odds ratio 11.2, P = 0.0259). Conclusions Half of the patients with cHCC-CCA had early recurrence after HR. Preoperative elevation of des-gamma carboxyprothrombin or carbohydrate antigen 19-9 and the existence of poorly differentiated components of HCC or CCA in resected specimens are predictors of its early recurrence.

Clinical predictive markers for the malignant potential of pancreatic neuroendocrine tumors (PNETs) are limited without histological investigation. We reported previously that a loss of the regular enhancement pattern in preoperative computed tomography (CT) was correlated with the malignant tumor phenotype. This study aimed to establish whether the metabolic aspect of the tumor evaluated by fludeoxyglucose (18F) positron emission tomography/computed tomography 18F-FDG PET/CT is associated with the tumor imaging characteristics and postoperative oncological outcome. Among 77 patients who underwent surgery with curative intent for a PNET at our institution between 2001 and 2017, 24 who received 18F-FDG PET/CT before surgery were enrolled in this study. The clinical importance of the standardized uptake value (SUVmax) was investigated with regard to tumor progression and prognosis after curative surgery. There were four (16%) patients with insulinoma. The mean tumor size was 17 mm and when the median value of the SUVmax (= 2.0) was measured as the cut-off value, the SUVmax ≥ 2.0 group (n = 12) was associated with large tumor size (p = 0.021), high tumor grade (p = 0.015), and irregular pattern on CT (p = 0.0055). The SUVmax was not correlated with age, gender, whether the tumor was functioning or non-functioning, or lymph node metastasis. The SUVmax ≥ 2.0 group had significantly poorer disease-free survival (median, 3.5 vs 16.2 months; p = 0.023) and poorer overall survival (median, 8.8 vs 16.2 months; p = 0.042). An SUVmax ≥ 2.0 on 18F-FDG PET/CT might be associated with higher malignant potential of PNETs.

Background Small hepatocellular carcinomas (HCC ≤3 cm) are generally considered to have low malignant potential; however, some of them display pathological microvascular invasion (MVI). Methods Between 1991 and 2013, 414 patients with a single HCC ≤3 cm underwent curative hepatic resection (HR). Predictors for MVI were identified. Using another cohort (149 patients during 2000‐2014), our predictors for MVI in HCC ≤3 cm were validated. In 428 patients with a single HCC ≤3 cm who had predictors for MVI, survival was compared among anatomical HR (n = 149), partial HR (n = 227), and radiofrequency ablation (RFA) (n = 52). Results The positive rate of MVI reached 40.6% (168/414 patients). Independent predictors for MVI were as follows: tumor diameter ≥2 cm (odds ratio 1.84, P = .0052), alpha‐fetoprotein (AFP) ≥200 ng/mL (odds ratio 1.82, P = .0466), and des‐gamma‐carboxy prothrombin (DCP) ≥40 mAU/mL (odds ratio 1.79, P = .0126). Matching at least one predictor among these three could predict MVI in HCC ≤3 cm well (sensitivity 82.8%, positive predictive value [PPV] 48.7%). This criterion could also predict MVI in HCC ≤3 cm well in another cohort (sensitivity 82.8%, PPV 30.3%). In patients with single HCC ≤3 cm matching our criterion for predicting MVI, anatomical HR led to significantly better survival in both disease‐free (hazard ratio 0.689, P = .0231) and overall (hazard ratio 0.589, P = .0316) survivals. Conclusion Matching at least one factor among three (tumor diameter ≥2 cm, AFP ≥200 ng/mL, or DCP ≥40 mAU/mL) can predict MVI in HCC ≤3 cm. In such patients, anatomical HR would be recommended to improve survival., Matching at least one factor among three (tumor diameter ≥2 cm, AFP ≥200 ng/mL, or DCP ≥40 mAU/mL) can predict MVI in HCC ≤3 cm. In such patients, anatomical HR should be recommended to improve survival.

Background/aim Prognoses of patients with cancer can be predicted on the basis of preoperative nutrition- or inflammation-based scores; however, predicting the prognostic impact of undergoing surgery remains challenging. In this study, we investigated the usefulness of the perioperative C-reactive protein/albumin (CRP/Alb) ratio in patients with intrahepatic cholangiocarcinoma (ICC). Patients and methods We retrospectively investigated 80 patients who had undergone curative resection of primary ICC between April 2002 and December 2017. We identified the time at which perioperative CRP/Alb ratio most influences the prognosis, and investigated the correlations among the perioperative CRP/Alb ratio, clinicopathological features and patient outcomes. Results The only perioperative CRP/Alb ratios significantly associated with shorter overall survival (OS) was a high CRP/Alb ratio on POD14. High CRP/Alb ratio on POD 14 was significantly associated with older age, male sex, and the presence of postoperative complications. Finally, a high CRP/Alb ratio at POD 14 was an independent prognostic factor for poor OS. Conclusion CRP/Alb ratio on POD 14 may be a useful prognostic factor in patients with ICC who have undergone curative resections.

Background Carcinosarcoma is a rare tumor that includes both carcinoma and sarcoma components. It develops commonly in the female reproductive tract, most often in the uterus. However, as there are a small number of similar cases in the English literature, we would like to present a rare case of a carcinosarcoma in Vater’s papilla. Case presentation A 76-year-old female patient was preoperatively diagnosed with a papillary adenocarcinoma in Vater’s papilla by endoscopic biopsy. The patient underwent subtotal stomach-preserving pancreaticoduodenectomy, and postoperative pathological examination diagnosed the carcinosarcoma. The patient received adjuvant chemotherapy with gemcitabine, but multiple liver metastases were found 3 months after the operation. Though chemotherapy with gemcitabine and cisplatin was introduced, she died owing to tumor progression 7 months after the operation. Conclusion Because carcinosarcoma of Vater’s papilla is a rare disease, a suitable treatment strategy has been unclear. We also present a review of the English literature regarding carcinosarcoma of Vater’s papilla.

Background Portal vein embolization has been used worldwide to induce hypertrophy of the future liver remnant and to reduce the risk of hepatic insufficiency and death after major hepatectomy. However, whether disease progression after portal vein embolization can affect long-term oncologic outcomes in patients with hepatocellular carcinoma is uncertain. Methods From a total of 107 patients who underwent portal vein embolization and subsequent hepatectomy between 2000 and 2016, 57 patients with hepatocellular carcinoma were enrolled. We evaluated their long-term oncologic outcomes and investigated whether the disease progression between portal vein embolization and subsequent hepatectomy affected survival. Results The 5-year overall survival and disease-free survival after hepatectomy were 74.5% and 31.7%, respectively. Multivariate analyses revealed that tumor number before hepatectomy ≥3 (hazard ratio 3.59, P = .019), des-γ-carboxy prothrombin >200 mAU/mL (hazard ratio 3.36, P = .045), and red blood cell transfusion (hazard ratio 11.03, P = .0008) were independent prognostic factors for overall survival. Male sex (hazard ratio 3.74, P = .029), bilobar tumor distribution (hazard ratio 3.65, P = .004), and red blood cell transfusion (hazard ratio 6.22, P = .0026) were independent prognostic factors for disease-free survival. Disease progressions after portal vein embolization, including increases in tumor size, tumor number, α-fetoprotein, lens culinaris agglutinin-reactive fraction of α-fetoprotein, and des-γ-carboxy prothrombin, were observed in 22.8%, 14.0%, 29.8%, 19.3%, and 47.4% of patients, respectively. Only an increase of tumor number significantly decreased the disease-free survival rate after hepatectomy in a univariate analysis, and none of the variables affected overall survival. Conclusion Disease progression after portal vein embolization did not affect long-term survival in patients with hepatocellular carcinoma if the planned subsequent hepatectomy could be completed.

Background The benefit of preoperative chemotherapy for colorectal liver metastases (CRLM) remains uncertain. The aim was to clarify the effect of preoperative chemotherapy on CRLM according to the primary tumor location. Methods Among a total cohort of 163 patients who underwent curative hepatectomy for CRLM, 36 patients had a right-sided and 127 had a left-sided primary tumor. According to the performance of preoperative chemotherapy, survival analysis was conducted and prognostic factors were identified. Results Preoperative chemotherapy was administered to 17 patients (47.2%) with a right-sided and 74 (58.3%) with a left-sided primary tumor (P = 0.24). Among the patients who received preoperative chemotherapy, overall survival (OS) and disease-free survival (DFS) were similar between patients with right- and left-sided primary tumors (P = 0.36 and P = 0.44, respectively). Among the patients who underwent upfront hepatectomy, the OS and DFS of patients with a right-sided primary tumor were worse than those with a left-sided primary tumor (P = 0.02 and P = 0.025, respectively). Among the patients who underwent upfront surgery, the right-sided primary tumor was identified as an independent poor prognostic factor for OS (hazard ratio 3.44, P = 0.021). Conclusion The existence of a right-sided primary tumor may be an indication of preoperative chemotherapy for patients with CRLM.

BACKGROUND/AIM The significance of microvascular invasion (MVI) of hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA) is unknown. PATIENTS AND METHODS We studied 149 patients with solitary small-sized HCC (≤3 cm) who underwent hepatectomy, and developed a predictive model of MVI using independent factors related to the presence of MVI. The predictive model was applied to 159 patients who underwent RFA, and their outcomes were examined. RESULTS A multivariate analysis revealed that α-fetoprotein ≥15 ng/ml (relative risk (RR) 3.05, p=0.02), des-γ-carboxy prothrombin ≥100 mAU/ml (RR 4.19, p=0.003), and tumor size ≥2 cm (RR 3.37, p=0.03) were independent risk factors of MVI. Among the patients who underwent RFA, the survival in patients with risk factors 2-3 was significantly worse, and local recurrence was more frequently obserbed than those with 0-1. CONCLUSION When an HCC tumor is expected to display MVI, RFA may not be suitable in terms of poorer survival and local disease-control rates.