Factors Affecting Nonfunctioning Small Pancreatic Neuroendocrine Neoplasms and Proposed New Treatment Strategies.

BACKGROUND & AIMS: Despite previously reported treatment strategies for nonfunctioning small (≤20 mm) pancreatic neuroendocrine neoplasms (pNENs), uncertainties persist. We aimed to evaluate the surgically resected cases of nonfunctioning small pNENs (NF-spNENs) in a large Japanese cohort to elucidate an optimal treatment strategy for NF-spNENs. METHODS: In this Japanese multicenter study, data were retrospectively collected from patients who underwent pancreatectomy between January 1996 and December 2019, were pathologically diagnosed with pNEN, and were treated according to the World Health Organization 2019 classification. Overall, 1490 patients met the eligibility criteria, and 1014 were included in the analysis cohort. RESULTS: In the analysis cohort, 606 patients (59.8%) had NF-spNENs, with 82% classified as grade 1 (NET-G1) and 18% as grade 2 (NET-G2) or higher. The incidence of lymph node metastasis (N1) by grade was significantly higher in NET-G2 (G1: 3.1% vs G2: 15.0%). Independent factors contributing to N1 were NET-G2 or higher and tumor diameter ≥15 mm. The predictive ability of tumor size for N1 was high. Independent factors contributing to recurrence included multiple lesions, NET-G2 or higher, tumor diameter ≥15 mm, and N1. However, the independent factor contributing to survival was tumor grade (NET-G2 or higher). The appropriate timing for surgical resection of NET-G1 and NET-G2 or higher was when tumors were >20 and >10 mm, respectively. For neoplasms with unknown preoperative grades, tumor size >15 mm was considered appropriate. CONCLUSIONS: NF-spNENs are heterogeneous with varying levels of malignancy. Therefore, treatment strategies based on tumor size alone can be unreliable; personalized treatment strategies that consider tumor grading are preferable.

A multi-institutional randomized phase III study comparing minimally invasive distal pancreatectomy versus open distal pancreatectomy for pancreatic cancer; Japan Clinical Oncology Group study JCOG2202 (LAPAN study).

BACKGROUND: Minimally invasive distal pancreatectomy (MIDP), including laparoscopic and robotic distal pancreatectomy, has gained widespread acceptance over the last decade owing to its favorable short-term outcomes. However, evidence regarding its oncologic safety is insufficient. In March 2023, a randomized phase III study was launched in Japan to confirm the non-inferiority of overall survival in patients with resectable pancreatic cancer undergoing MIDP compared with that of patients undergoing open distal pancreatectomy (ODP). METHODS: This is a multi-institutional, randomized, phase III study. A total of 370 patients will be enrolled from 40 institutions within 4 years. The primary endpoint of this study is overall survival, and the secondary endpoints include relapse-free survival, proportion of patients undergoing radical resection, proportion of patients undergoing complete laparoscopic surgery, incidence of adverse surgical events, and length of postoperative hospital stay. Only a credentialed surgeon is eligible to perform both ODP and MIDP. All ODP and MIDP procedures will undergo centralized review using intraoperative photographs. The non-inferiority of MIDP to ODP in terms of overall survival will be statistically analyzed. Only if non-inferiority is confirmed will the analysis assess the superiority of MIDP over ODP. DISCUSSION: If our study demonstrates the non-inferiority of MIDP in terms of overall survival, it would validate its short-term advantages and establish its long-term clinical efficacy. TRIAL REGISTRATION: This trial is registered with the Japan Registry of Clinical Trials as jRCT 1,031,220,705 [ https://jrct.niph.go.jp/en-latest-detail/jRCT1031220705 ].

FBXW7 regulates the sensitivity of imatinib in gastrointestinal stromal tumors by targeting MCL1.

BACKGROUND: Imatinib contributes to improving prognosis of high-risk or unresectable gastrointestinal stromal tumors (GISTs). As therapeutic efficacy is limited by imatinib resistance and toxicity, the exploration of predictive markers of imatinib therapeutic efficacy that enables patients to utilize more effective therapeutic strategies remains urgent. METHODS: The correlation between FBXW7 and imatinib resistance via FBXW7-MCL1 axis was evaluated in vitro and in vivo experiments. The significance of FBXW7 as a predictor of imatinib treatment efficacy was examined in 140 high-risk patients with GISTs. RESULTS: The ability of FBXW7 to predict therapeutic efficacy of adjuvant imatinib in high-risk GIST patients was determined through 5-year recurrence-free survival (RFS) rates analysis and multivariate analysis. FBXW7 affects imatinib sensitivity by regulating apoptosis in GIST-T1 cells. FBXW7 targets MCL1 to regulate apoptosis. MCL1 involves in the regulation of imatinib sensitivity through inhibiting apoptosis in GIST-T1 cells. FBXW7 regulates imatinib sensitivity by down-regulating MCL1 to enhance imatinib-induced apoptosis in vitro. FBXW7 regulates imatinib sensitivity of GIST cells by targeting MCL1 to predict efficacy of imatinib treatment in vivo. CONCLUSIONS: FBXW7 regulates imatinib sensitivity by inhibiting MCL1 to enhance imatinib-induced apoptosis in GIST, and predicts efficacy of imatinib treatment in high-risk GIST patients treated with imatinib.

Predictive risk factors for resection surface-related complications after laparoscopic simultaneous resection of primary colorectal tumor and synchronous liver metastases: a single-center retrospective study.

BACKGROUND: Laparoscopic simultaneous resection (LSR) of primary colorectal tumors and synchronous colorectal liver metastases (sCRLM) has been recently performed. This study aimed to evaluate the postoperative outcomes after LSR and determine the risk factors for resection surface-related complications (RSRC), such as postoperative biliary fistula and liver-transection surface abscess. METHODS: Between 2009 and 2022, consecutive patients with sCRLM who underwent LSR were included. We retrospectively analyzed clinicopathological data, including intraoperative factors and postoperative outcomes. The difficulty level of all liver resections was classified according to the IWATE difficulty scoring system (DSS). We then performed univariate and multivariate analyses to identify the risk factors for RSRC. RESULTS: Of the 112 patients, 94 (83.9%) underwent partial hepatectomy and colorectal surgery. The median DSS score was 5 points (1-11), with 12 (10.7%) patients scoring ≥ 7 points. Postoperative complications were observed in 41 (36.6%) patients, of whom 16 (14.3%) experienced severe complications classified as Clavien-Dindo grade IIIa or higher. There was no postoperative mortality. The most common complication was RSRC (19 patients, 17.0%). Multivariate analysis identified American Society of Anesthesiologists (ASA) classification ≥ 3 [odds ratio (OR) 10.3, 95% confidence interval (CI) 1.37-77.8; P = 0.023], DSS score ≥ 7 points (OR 5.08, 95% CI 1.17-20.0; P = 0.030), and right-sided colectomy (OR 4.67, 95% CI 1.46-15.0; P = 0.009) as independent risk factors for RSRC. Postoperative hospital stays were significantly longer for patients with RSRC than for those without RSRC (22 days vs. 11 days; P < 0.001). CONCLUSION: Short-term outcomes of LSR for patients with sCRLM were acceptable in an experienced center. RSRC was the most common complication, and high-difficulty hepatectomy, right-sided colectomy, and ASA classification ≥ 3 were independent risk factors for RSRC.

Intraoperative artificial intelligence system identifying liver vessels in laparoscopic liver resection: a retrospective experimental study.

BACKGROUND: The precise recognition of liver vessels during liver parenchymal dissection is the crucial technique for laparoscopic liver resection (LLR). This retrospective feasibility study aimed to develop artificial intelligence (AI) models to recognize liver vessels in LLR, and to evaluate their accuracy and real-time performance. METHODS: Images from LLR videos were extracted, and the hepatic veins and Glissonean pedicles were labeled separately. Two AI models were developed to recognize liver vessels: the "2-class model" which recognized both hepatic veins and Glissonean pedicles as equivalent vessels and distinguished them from the background class, and the "3-class model" which recognized them all separately. The Feature Pyramid Network was used as a neural network architecture for both models in their semantic segmentation tasks. The models were evaluated using fivefold cross-validation tests, and the Dice coefficient (DC) was used as an evaluation metric. Ten gastroenterological surgeons also evaluated the models qualitatively through rubric. RESULTS: In total, 2421 frames from 48 video clips were extracted. The mean DC value of the 2-class model was 0.789, with a processing speed of 0.094 s. The mean DC values for the hepatic vein and the Glissonean pedicle in the 3-class model were 0.631 and 0.482, respectively. The average processing time for the 3-class model was 0.097 s. Qualitative evaluation by surgeons revealed that false-negative and false-positive ratings in the 2-class model averaged 4.40 and 3.46, respectively, on a five-point scale, while the false-negative, false-positive, and vessel differentiation ratings in the 3-class model averaged 4.36, 3.44, and 3.28, respectively, on a five-point scale. CONCLUSION: We successfully developed deep-learning models that recognize liver vessels in LLR with high accuracy and sufficient processing speed. These findings suggest the potential of a new real-time automated navigation system for LLR.

Explainable artificial intelligence prediction-based model in laparoscopic liver surgery for segments 7 and 8: an international multicenter study.

BACKGROUND: Artificial intelligence (AI) is becoming more useful as a decision-making and outcomes predictor tool. We have developed AI models to predict surgical complexity and the postoperative course in laparoscopic liver surgery for segments 7 and 8. METHODS: We included patients with lesions located in segments 7 and 8 operated by minimally invasive liver surgery from an international multi-institutional database. We have employed AI models to predict surgical complexity and postoperative outcomes. Furthermore, we have applied SHapley Additive exPlanations (SHAP) to make the AI models interpretable. Finally, we analyzed the surgeries not converted to open versus those converted to open. RESULTS: Overall, 585 patients and 22 variables were included. Multi-layer Perceptron (MLP) showed the highest performance for predicting surgery complexity and Random Forest (RF) for predicting postoperative outcomes. SHAP detected that MLP and RF gave the highest relevance to the variables "resection type" and "largest tumor size" for predicting surgery complexity and postoperative outcomes. In addition, we explored between surgeries converted to open and non-converted, finding statistically significant differences in the variables "tumor location," "blood loss," "complications," and "operation time." CONCLUSION: We have observed how the application of SHAP allows us to understand the predictions of AI models in surgical complexity and the postoperative outcomes of laparoscopic liver surgery in segments 7 and 8.

Common clinicopathological and immunological features of sarcomatoid carcinoma across organs: A histomorphology-based cross-organ study.

Sarcomatoid carcinoma (SC), which can occur in any organ, is a rare disease. To elucidate common characteristics of SC beyond organs, we evaluated clinicopathological and immunological features of SC defined by the single histological criterion beyond organs compared to randomly matched conventional carcinoma (non-SC) adjusted for the disease stage. Immunological features were assessed by multiplex immunohistochemistry, comparing immune cell density in tumor tissues and tumor programmed death-ligand 1 (PD-L1) expression. A total of 101 patients with SC or non-SC (31 lung, 19 esophagus, 22 pancreas, 15 liver, 4 bile duct, 6 kidney, 2 uterus and 2 ovary) were identified among 7197 patients who underwent surgery at our institute (1997-2020). SC was significantly associated with worse survival (HR: 1.571; 95% CI: 1.084-2.277; P = .017). The frequency of postoperative progression within 6 months was significantly higher for SC patients (54% vs 28%; P = .002). The immune profiling revealed the densities of CD8+ T cells (130 vs 72 cells/mm2 ; P = .004) and tumor-associated macrophages (566 vs 413 cells/mm2 ; P < .0001) and the tumor PD-L1 expression score (40% vs 5%; P < .0001) were significantly higher in SCs than in non-SCs. Among 73 SC patients with postoperative progression, multivariate Cox regression analysis showed that immunotherapy tended to be associated with favorable survival (HR: 0.256; 95% CI: 0.062-1.057; P = .060). Collectively, SCs shared clinicopathological and immunological features across organs. Our study can initiate to standardize the pathological definition of SC and provide a rationale for the investigation and development for this rare disease in a cross-organ manner.

Relationships between physical and immunological tumor microenvironment in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is physically palpated as a hard tumor with an unfavorable prognosis. Assessing physical features and their association with pathological features could help to elucidate the mechanism of physical abnormalities in cancer tissues. A total of 93 patients who underwent radical surgery for pancreatic and bile duct cancers at a single center hospital during a 28-month period were recruited for this study that aimed to estimate the stiffness of PDAC tissues compared to the other neoplasms and assess relationships between tumor stiffness and pathological features. Physical alterations and pathological features of PDAC, with or without preoperative therapy, were analyzed. The immunological tumor microenvironment was evaluated using multiplexed fluorescent immunohistochemistry. The stiffness of PDAC correlated with the ratio of Azan-Mallory staining, α-smooth muscle actin, and collagen I-positive areas of the tumors. Densities of CD8+ T cells and CD204+ macrophages were associated with tumor stiffness in cases without preoperative therapy. Pancreatic ductal adenocarcinoma treated with preoperative therapy was softer than that without, and the association between tumor stiffness and immune cell infiltration was not shown after preoperative therapy. We observed the relationship between tumor stiffness and immunological features in human PDAC for the first time. Immune cell densities in the tumor center were smaller in hard tumors than in soft tumors without preoperative therapies. Preoperative therapy could alter physical and immunological aspects, warranting further study. Understanding of the correlations between physical and immunological aspects could lead to the development of new therapies.

Machine learning-based Automatic Evaluation of Tissue Handling Skills in Laparoscopic Colorectal Surgery: A Retrospective Experimental Study.

OBJECTIVE: To develop a machine learning model that automatically quantifies the spread of blood in the surgical field using intraoperative videos of laparoscopic colorectal surgery and evaluate whether the index measured with the developed model can be used to assess tissue handling skill. BACKGROUND: Although skill evaluation is crucial in laparoscopic surgery, existing evaluation systems suffer from evaluator subjectivity and are labor-intensive. Therefore, automatic evaluation using machine learning is potentially useful. MATERIALS AND METHODS: In this retrospective experimental study, we used training data with annotated labels of blood or non-blood pixels on intraoperative images to develop a machine learning model to classify pixel RGB values into blood and non-blood. The blood pixel count per frame (the total number of blood pixels throughout a surgery divided by the number of frames) was compared among groups of surgeons with different tissue handling skills. RESULTS: The overall accuracy of the machine learning model for the blood classification task was 85.7%. The high tissue handling skill group had the lowest blood pixel count per frame, and the novice surgeon group had the highest count (mean [SD]: high tissue handling skill group 20972.23 [19287.05] vs. low tissue handling skill group 34473.42 [28144.29] vs. novice surgeon group 50630.04 [42427.76], P <0.01). The difference between any 2 groups was significant. CONCLUSIONS: We developed a machine learning model to measure blood pixels in laparoscopic colorectal surgery images using RGB information. The blood pixel count per frame measured with this model significantly correlated with surgeons' tissue handling skills.

A novel predictive model for postoperative delirium using multiple geriatric screening factors.

OBJECTIVES: The purpose of this study was to develop a new composite score to accurately predict postoperative delirium (POD) after major urological cancer surgery. METHODS: Our retrospective analysis included, in total, 449 consecutive patients who experienced major urological cancer surgery and a preoperative geriatric functional assessment at our institution (development cohort). Geriatric functional assessments included Geriatric 8, Instrumental Activities of Daily Living, and mini-cognitive assessment instrument (Mini-Cog). Multivariate analysis was used to identify factors related to POD and combined to create a predictive score. The composite score was externally validated using a cohort of 92 consecutive pancreatic cancer patients who underwent pancreaticoduodenectomy and a preoperative geriatric functional assessment (validation cohort). The predictive accuracy and performance of the composite score were evaluated using the area under the receiver operating characteristic curves (AUC) and calibration plots. RESULTS: In multivariate analysis of a development cohort, the following factors were significantly associated with POD: a Mini-Cog score of <3 (odds ratio [OR] = 9.5; p < 0.001), disability in the responsibility for medication (OR = 4.1; p = 0.03), and the preoperative use of benzodiazepine (OR = 6.4; p < 0.001). The composite score of these three factors showed excellent discrimination in predicting POD, with AUC values of 0.819 and 0.804 in development and validation cohorts, respectively. Calibration plots showing predicted probability and actual observation in both cohorts showed good agreement. CONCLUSIONS: A combined model of Mini-Cog, a disability in the responsibility for medication, and preoperative benzodiazepine use showed excellent discriminative power in predicting POD.

Adjuvant and neoadjuvant chemotherapy for biliary tract cancer: a review of randomized controlled trials.

The first randomized controlled trial of adjuvant chemotherapy for biliary tract cancer was reported in 2002. Since then, studies have continued, with efficacy reported for capecitabine in 2018 and S-1 in 2023. Oral fluoropyrimidines have become established as the standard of care. This article reviews the evidence from the randomized controlled trials reported to date and those that are ongoing or from which results have not yet been reported.

Liver functional assessment using time-associated change in the liver-to-spleen signal intensity ratio on enhanced magnetic resonance imaging: a retrospective study.

BACKGROUND: Liver-to-spleen signal intensity ratio (LSR) is evaluated by magnetic resonance imaging (MRI) in the hepatobiliary phase and has been reported as a useful radiological assessment of regional liver function. However, LSR is a passive (non-time-associated) assessment of liver function, not a dynamic (time-associated) assessment. Moreover, LSR shows limitations such as a dose bias of contrast medium and a timing bias of imaging. Previous studies have reported the advantages of time-associated liver functional assessment as a precise assessment of liver function. For instance, the indocyanine green (ICG) disappearance rate, which is calculated from serum ICG concentrations at multiple time points, reflects a precise preoperative liver function for predicting post-hepatectomy liver failure without the dose bias of ICG or the timing bias of blood sampling. The aim of this study was to develop a novel time-associated radiological liver functional assessment and verify its correlation with traditional liver functional parameters. METHODS: A total of 279 pancreatic cancer patients were evaluated to clarify fundamental time-associated changes to LSR in normal liver. We defined the time-associated radiological assessment of liver function, calculated using information on LSR from four time points, as the "LSR increasing rate" (LSRi). We then investigated correlations between LSRi and previous liver functional parameters. Furthermore, we evaluated how timing bias and protocol bias affect LSRi. RESULTS: Significant correlations were observed between LSRi and previous liver functional parameters such as total bilirubin, Child-Pugh grade, and albumin-bilirubin grade (P < 0.001 each). Moreover, considerably high correlations were observed between LSRi calculated using four time points and that calculated using three time points (r > 0.973 each), indicating that the timing bias of imaging was minimal. CONCLUSIONS: This study propose a novel time-associated radiological assessment, and revealed that the LSRi correlated significantly with traditional liver functional parameters. Changes in LSR over time may provide a superior preoperative assessment of regional liver function that is better for predicting post-hepatectomy liver failure than LSR using the hepatobiliary phase alone.

Component with abundant immune-related cells in combined hepatocellular cholangiocarcinoma identified by cluster analysis.

Combined hepatocellular cholangiocarcinoma (cHCC-CCA) is a heterogeneous tumor sharing histological features with hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA). The tumor immune microenvironment (TIME) of cHCC-CCA is unclear. We compared the TIME of cHCC-CCA with that of HCC and iCCA. Twenty-three patients with cHCC-CCA after hepatectomy were evaluated in this study. Twenty-three patients with iCCA and HCC were also included. iCCA was matched for size, and HCC was matched for size and hepatitis virus infection with cHCC-CCA. Immune-related cells among the iCCA-component of cHCC-CCA (C-com), HCC-component of cHCC-CCA (H-com), iCCA, and HCC were assessed using multiplex fluorescence immunohistochemistry. Among C-com, H-com, iCCA, and HCC, multiple comparisons and cluster analysis with k-nearest neighbor algorithms were performed using immunological variables. Although HCC had more T lymphocytes and lower PD-L1 expression than iCCA (P < 0.05), there were no significant differences in immunological variables between C-com and H-com. C-com tended to have more T lymphocytes than iCCA (P = 0.09), and C-com and H-com had fewer macrophages than HCC (P < 0.05). In cluster analysis, all samples were classified into two clusters: one cluster had more immune-related cells than the other, and 12 of 23 H-com and eight of 23 C-com were identified in this cluster. The TIME of C-com and H-com may be similar, and some immunological features in these components were different from those in HCC and some iCCA. Cluster analysis identified components with abundant immune-related cells in cHCC-iCCA.

Early postoperative decrease of skeletal muscle mass predicts recurrence and poor survival after surgical resection for perihilar cholangiocarcinoma.

BACKGROUND: Preoperative sarcopenia is a predictor of poor survival in cancer patients. We hypothesized that sarcopenia could progress as occult metastasis arose, especially after highly invasive surgery for highly aggressive malignancy. This study aimed to evaluate the associations of postoperative changes in skeletal muscle mass volume with survival outcomes in patients who underwent surgery for perihilar cholangiocarcinoma. METHODS: Fifty-six patients who underwent major hepatectomy with extrahepatic bile duct resection for perihilar cholangiocarcinoma were studied. The skeletal muscle index (SMI) at the third lumbar vertebra was calculated from axial computed tomography images taken preoperatively and 3-6 months postoperatively (early postoperative period). The associations of clinicopathological variables, including changes of SMI after surgery, with overall survival and recurrence-free survival were evaluated. Moreover, the associations of decreased SMI and elevated serum carbohydrate antigen 19-9 level with early recurrence and poor survival was compared. RESULTS: Among 56 patients, 26 (46%) had sarcopenia preoperatively and SMI decreased in 29 (52%) in the early postoperative period. During the median follow-up of 57.9 months, 35 patients (63%) developed recurrence and 29 (50%) died. Decreased SMI in the early postoperative period was independently associated with a shorter overall survival (hazard ratio, 2.39; 95% confidence interval, 1.00-6.18; P = 0.049) and a shorter recurrence-free survival (hazard ratio, 2.14; 95% confidence interval, 1.04-4.57; P = 0.039), whereas elevated carbohydrate antigen 19-9 level was not. CONCLUSIONS: Decreased SMI in the early postoperative period may be used as a predictor for recurrence and poor survival in patients undergoing surgery for perihilar cholangiocarcinoma.

Laparoscopic liver resection can be performed safely without intraoperative drain placement.

BACKGROUND: Laparoscopic liver resection (LLR) has become a standardized procedure with advances in surgical techniques and perioperative management in the last decade; however, the necessity of routine drain placement in LLR has not been fully investigated. This study aimed to evaluate the need for intraoperative drain placement (IDP) in LLR. METHODS: A total of 607 patients who underwent LLR for liver tumor at our institution between January 2015 and August 2021 were studied. Clinicopathological data, including intraoperative factors and postoperative outcomes, were compared between patients with and without IDP before and after propensity score matching. Variables shown to be different between the two groups were used for matching. Then, risk analysis for additional drainage procedure after surgery was performed in the original and matched cohorts. RESULTS: Of the 607 patients, 4 (0.7%) and 14 (2.3%) developed incisional and organ/space surgical site infections, respectively, and 9 (1.5%) required additional drainage procedure after surgery. Ninety-three patients (15.3%) underwent IDP. The incidence and severity of postoperative complications were similar between patients with and without IDP in both the original and matched cohorts. In the matched cohort, simultaneous colectomy (odds ratio, 14.051, 95% confidence interval, 1.103-178.987; P = 0.042), rather than IDP (odds ratio, 1.836, 95% confidence interval, 0.157-21.509; P = 0.629), was independently associated with the risk of additional drainage procedure after surgery. CONCLUSIONS: This study demonstrated that LLR could be performed safely without IDP.

Sarcomatoid hepatocellular carcinoma is distinct from ordinary hepatocellular carcinoma: Clinicopathologic, transcriptomic and immunologic analyses.

Sarcomatoid hepatocellular carcinoma (SHCC), which was a rare histological subtype of hepatocellular carcinoma (HCC), is currently subclassified as poorly differentiated HCC because of insufficient evidence to define SHCC as a subtype of HCC. We aimed to assess the feasibility of classifying SHCC as a histological subtype of HCC by comprehensively identifying novel and distinct characteristics of SHCC compared to ordinary HCC (OHCC). Fifteen SHCCs (1.4%) defined as HCC with at least a 10% sarcomatous component, 15 randomly disease-stage-matched OHCCs and 163 consecutive OHCCs were extracted from 1106 HCCs in the Pathology Database (1997-2019) of our hospital. SHCC patients showed poor prognosis, and the tumors could be histologically subclassified into the pleomorphic, spindle and giant cell types according to the subtype of carcinomas with sarcomatoid or undifferentiated morphology in other organs. The transcriptomic analysis revealed distinct characteristics of SHCC featuring the upregulation of genes associated with epithelial-to-mesenchymal transition and inflammatory responses. The fluorescent multiplex immunohistochemistry results revealed prominent programmed death-ligand 1 (PD-L1) expression on sarcomatoid tumor cells and higher infiltration of CD4+ and CD8+ T cells in SHCCs compared to OHCCs. The density of CD8+ T cells in the nonsarcomatous component of SHCCs was also higher than that in OHCCs. In conclusion, the comprehensive analyses in our study demonstrated that SHCC is distinct from OHCC in terms of clinicopathologic, transcriptomic and immunologic characteristics. Therefore, it is reasonable to consider SHCC as a histological subtype of HCC.

The immunological impact of preoperative chemoradiotherapy on the tumor microenvironment of pancreatic cancer.

Several therapeutic regimens, including neoadjuvant chemoradiation therapy (NACRT), have been reported to serve as anticancer immune effectors. However, there remain insufficient data regarding the immune response after NACRT in pancreatic ductal adenocarcinoma (PDAC) patients. Data from 40 PDAC patients that underwent surgical resection after NACRT (NACRT group) and 30 PDAC patients that underwent upfront surgery (US group) were analyzed to examine alterations in immune cell counts/distribution using a multiplexed fluorescent immunohistochemistry system. All immune cells were more abundant in the cancer stroma than in the cancer cell nest regardless of preoperative therapy. Although the stromal counts of CD4+ T cells, CD20+ B cells, and Foxp3+ T cells in the NACRT group were drastically decreased in comparison with those of the US group, counts of these cell types in the cancer cell nest were not significantly different between the two groups. In contrast, CD204+ macrophage counts in the cancer stroma were similar between the NACRT and US groups, while those in the cancer cell nests were significantly reduced in the NACRT group. Following multivariate analysis, only a high CD204+ macrophage count in the cancer cell nest remained an independent predictor of shorter relapse-free survival (odds ratio = 2.37; P = .033). NACRT for PDAC decreased overall immune cell counts, but these changes were heterogeneous within the cancer cell nests and cancer stroma. The CD204+ macrophage count in the cancer cell nest is an independent predictor of early disease recurrence in PDAC patients after NACRT.

Impact of Preoperative Circulating Tumor DNA Status on Survival Outcomes After Hepatectomy for Resectable Colorectal Liver Metastases.

BACKGROUND: The optimal perioperative management of patients who undergo hepatectomy for resectable colorectal liver metastases (CRLM) remains unclear due to the lack of reliable methods to stratify the risk of recurrence. METHODS: A single-center retrospective study was performed to investigate the impact of preoperative circulating tumor DNA (ctDNA) on survival outcomes of patients who underwent initial hepatectomy for solitary resectable CRLM between January 2005 and December 2017 using the comprehensive genotyping platform Guardant360®. RESULTS: Of 212 patients who underwent initial hepatectomy for solitary resectable CRLM, 40 patients for whom pre-hepatectomy plasma was available underwent ctDNA analysis. Among them, 32 (80%) had at least 1 somatic alteration in their ctDNA, while the other 8 (20%) had no detectable ctDNA. Among the patients with undetectable ctDNA, only one had recurrence and none died during a median follow-up period of 39.0 months. The recurrence-free survival was significantly shorter in patients who were positive for ctDNA than in those who were negative for ctDNA [median, 12.5 months vs not reached (NR); HR, 7.6; P = 0.02]. The overall survival also tended to be shorter in patients who were positive for ctDNA than those who were negative for ctDNA (median, 78.1 months vs NR; P = 0.14; HR not available). CONCLUSIONS: In patients undergoing hepatectomy for solitary resectable CRLM, the absence of detectable preoperative ctDNA identified patients with a high chance for a cure. Risk stratification according to preoperative ctDNA analysis may be an effective tool that can improve the perioperative management of these patients.

The potential application of PD-1 blockade therapy for early-stage biliary tract cancer.

Biliary tract cancer (BTC) is an aggressive cancer with a poor prognosis partially due to the limited success in developing novel therapies, including molecularly targeted therapies and immunotherapies. Programmed cell death-1 (PD-1) blockade therapy is less effective against BTCs, necessitating further studies to understand the detailed immunological status of the tumor microenvironment (TME) in BTC. Here, we examined the immunological status of the TME in 37 BTCs with early- to late-stage disease, especially focusing on PD-1+CD8+ T cells. PD-1+CD8+ T cells, which are reportedly associated with the clinical response to PD-1 blockade therapy, were frequently observed in early-stage BTC and decreased with disease progression. Imaging mass cytometry for representative PD-1+CD8+TIL-high and -low patients demonstrated that tumor-infiltrating PD-1+CD8+ T cells were localized adjacent to tumor cells, whereas PD-1-CD8+ T cells were detected mainly in the stroma of the TME. In a mouse model, PD-1 expression by tumor-infiltrating CD8+ T cells was higher in smaller tumors and decreased with tumor growth. Consequently, large tumors became resistant to PD-1 blockade, while small tumors containing higher numbers of PD-1+CD8+ T cells were sensitive. We propose the important role of tumor-infiltrating PD-1+CD8+ T cells in anti-tumor immunity and the potential application of PD-1 blockade therapy for early-stage BTC.

Peptide vaccine as an adjuvant therapy for glypican-3-positive hepatocellular carcinoma induces peptide-specific CTLs and improves long prognosis.

There is no established postoperative adjuvant therapy for hepatocellular carcinoma (HCC), and improvement of patient prognosis has been limited. We conducted long-term monitoring of patients within a phase II trial that targeted a cancer antigen, glypican-3 (GPC3), specifically expressed in HCC. We sought to determine if the GPC3 peptide vaccine was an effective adjuvant therapy by monitoring disease-free survival and overall survival. We also tracked GPC3 immunohistochemical (IHC) staining, CTL induction, and postoperative plasma GPC3 for a patient group that was administered the vaccine (n = 35) and an unvaccinated patient group that underwent surgery only (n = 33). The 1-y recurrence rate after surgery was reduced by approximately 15%, and the 5-y and 8-y survival rates were improved by approximately 10% and 30%, respectively, in the vaccinated group compared with the unvaccinated group. Patients who were positive for GPC3 IHC staining were more likely to have induced CTLs, and 60% survived beyond 5 y. Vaccine efficacy had a positive relationship with plasma concentration of GPC3; high concentrations increased the 5-y survival rate to 75%. We thus expect GPC3 vaccination in patients with HCC, who are positive for GPC3 IHC staining and/or plasma GPC3 to induce CTL and have significantly improved long-term prognosis.