Safety and efficacy of neoadjuvant chemoradiotherapy with moderately hypofractionated intensity-modulated radiotherapy for resectable pancreatic cancer: A prospective, open-label, phase II study.

BACKGROUND: Resectable pancreatic cancer (RPC) is potentially resectable on admission, and the impact of neoadjuvant therapy on these tumors is controversial. Moreover, the safety and efficacy of neoadjuvant chemoradiotherapy with moderately hypofractionated intensity-modulated radiation therapy (NACIMRT) for RPC have not been studied. Here, we conducted a phase II study to evaluate the safety and efficacy of hypofractionated NACIMRT for RPC. METHODS: A total of 54 RPC patients were enrolled and treated according to the study protocol. We used moderately hypofractionated (45 Gy in 15 fractions) IMRT with gemcitabine to shorten the duration of radiotherapy and reduce gastrointestinal toxicity. The primary endpoint was overall survival (OS), and we subsequently analyzed the microscopically margin-negative resection (R0) rate, disease-free survival (DFS), and histologic effects and safety of NACIMRT. RESULTS: Median OS for the cohort was 40.0 months. Forty-two patients (77.8%) underwent pancreatectomy after NACIMRT. Median DFS was 20.3 months. The R0 resection rate was 95.2% (40/42) per protocol and 85.2% (46/54) for the cohort. There were no intervention-related deaths during the study period. Local treatment response, as assessed by the CAP classification, showed no residual tumor in 4.8% of patients. Overall, 23.9% of patients experienced CTCAE grade 3 or 4 during NACIMRT. Adjuvant therapy was initiated in 88% of patients undergoing resection. Postoperative complications grade ≥3b on the Clavien-Dindo scale occurred in 4.8% of patients. CA19-9 level at enrollment was an independent prognostic factor for OS and DFS. CONCLUSIONS: This is the first prospective study of hypofractionated IMRT as neoadjuvant therapy for RPC. Hypofractionated NACIMRT for RPC could be safely introduced with a high induction rate of adjuvant chemotherapy, with an overall survival of 40.0 months.

Preoperative Endoscopic Minor Papilla Sphincterotomy for Pancreas Divisum in a Patient with Pancreatic Cancer Who Underwent Laparoscopic Distal Pancreatectomy.

BACKGROUND: Pancreas divisum (PD) is a congenital anomaly that occurs due to failure of fusion of the dorsal and ventral pancreatic ductal systems.1-3 In PD, pancreatic juice drains mainly through the minor papilla via the dorsal duct, leading to high intraductal pressure, which can cause pancreatitis.1-3 We report a case of PD that underwent preoperative decompression using endoscopic minor papilla sphincterotomy (EMPS) before laparoscopic distal pancreatectomy (LDP) for pancreatic cancer.3 METHODS: The patient was a 74-year-old woman with pancreatic tail cancer, measuring 35 mm in size, in PD with an entirely dilated dorsal duct, implying high, intraductal pressure caused by minor papillary dysfunction. We performed EMPS to prevent postoperative pancreatitis and pancreatic fistula before LDP using a left-posterior approach, as previously described.4 As the pancreatic transection margin was positive for high-grade pancreatic intraepithelial neoplasia on intraoperative pathology, an additional resection of the pancreatic head to the right side of the portal vein was performed after the liberation of the gastroduodenal artery with both the dorsal and ventral pancreatic ducts ligated and divided. RESULTS: The operative time was 421 min, and blood loss was 70 mL. The postoperative course was uneventful, with no evidence of pancreatitis or pancreatic fistula. The patient was discharged on postoperative Day 10. Postoperative computed tomography revealed reduced dilatation of the dorsal duct. CONCLUSIONS: Preoperative EMPS may be effective in preventing pancreatic fistula after LDP in patients with PD.

Mixed acinar-neuroendocrine carcinoma of the pancreas with positive for microsatellite instability: a case report and review of the literature.

BACKGROUND: Mixed acinar-neuroendocrine carcinoma (MANEC) of the pancreas is a rare tumor. We report a case of successful surgical resection of expansively growing MANEC of the pancreas with microsatellite instability (MSI)-high. CASE PRESENTATION: The patient was an asymptomatic 65-year-old male. A computed tomography (CT) scan for a follow-up after treatment of pneumonia incidentally revealed a hypoenhancing 12-cm expansively growing tumor in the pancreatic body. An endoscopic ultrasound-guided fine-needle aspiration of the tumor suggested the diagnosis of MANEC. We performed distal pancreatectomy with combined resection of the spleen, left adrenal gland, transverse colon, small bowel, and stomach. The intraoperative findings showed that the tumor was capsular and was in contact with the SMA, SMV, and CA; however, obvious infiltration of these vessels was not observed..Pathological findings indicated MANEC with MSI-high. Among mismatch repair (MMR) gene proteins, PMS2 was lost and MLH1, MSH2, and MSH6 were retained. The tumor recurred 5 months after surgery. The patient was treated with gemcitabine plus nab-paclitaxel followed by pembrolizumab, which did not show objective response. DISCUSSION: This is the first report investigating MSI and MMR in MANEC. Standard chemotherapy has not been established for MANEC. Detection of MSI-high is essential since PD-1 monoclonal antibodies for MSI-high cases might be one of the good treatment options. Herein, we discuss the various cytomorphologic and clinical features of MANEC and present a brief review of the literatures. CONCLUSIONS: The accumulation of data from additional cases is necessary to further evaluate this type of carcinoma and provide a standardized optimal therapy for MANEC.

Metastatic colorectal adenocarcinoma tumor purity assessment from whole exome sequencing data.

Tumors rich in stroma are associated with advanced stage and poor prognosis in colorectal adenocarcinoma (CRC). Abundance of stromal cells also has implications for genomic analysis of patient tumors as it may prevent detection of somatic mutations. As part of our efforts to interrogate stroma-cancer cell interactions and to identify actionable therapeutic targets in metastatic CRC, we aimed to determine the proportion of stroma embedded in hepatic CRC metastases by performing computational tumor purity analysis based on whole exome sequencing data (WES). Unlike previous studies focusing on histopathologically prescreened samples, we used an unbiased in-house collection of tumor specimens. WES from CRC liver metastasis samples were utilized to evaluate stromal content and to assess the performance of three in silico tumor purity tools, ABSOLUTE, Sequenza and PureCN. Matching tumor derived organoids were analyzed as a high purity control as they are enriched in cancer cells. Computational purity estimates were compared to those from a histopathological assessment conducted by a board-certified pathologist. According to all computational methods, metastatic specimens had a median tumor purity of 30% whereas the organoids were enriched for cancer cells with a median purity estimate of 94%. In line with this, variant allele frequencies (VAFs) of oncogenes and tumor suppressor genes were undetectable or low in most patient tumors, but higher in matching organoid cultures. Positive correlation was observed between VAFs and in silico tumor purity estimates. Sequenza and PureCN produced concordant results whereas ABSOLUTE yielded lower purity estimates for all samples. Our data shows that unbiased sample selection combined with molecular, computational, and histopathological tumor purity assessment is critical to determine the level of stroma embedded in metastatic colorectal adenocarcinoma.

Propensity Score Matching Analysis of the Safety of Completion Total Pancreatectomy for Remnant Pancreatic Tumors Versus that of Initial Total Pancreatectomy for Primary Pancreatic Tumors.

BACKGROUND: The safety and feasibility of completion total pancreatectomy (TP) for remnant pancreatic neoplasms remain controversial and are rarely compared with that of initial TP. Thus, we aimed to compare the safety of these two procedures inducing a pancreatic state. METHODS: Patients who underwent TP for pancreatic neoplasms between 2006 and 2018 at our institution were included in this study. Tumor pathologies were classified into three subgroups according to survival curves. We used 1:1 propensity score matching (PSM) to analyze age, sex, Charlson Comorbidity Index, and tumor stage. Finally, we analyzed the primary outcome Clavien-Dindo classification (CDC) grade, risks of other safety-related outcomes, and the survival rate of patients with invasive cancer. RESULTS: Of 54 patients, 16 underwent completion TP (29.6%) and 38 (70.4%) underwent initial TP. Before PSM analysis, age and Charlson Comorbidity Index were significantly higher, and T category and stage were significantly lower for the completion TP group. Upon PSM analysis, these two groups were equivalent in CDC grade [initial TP vs. completion TP: 71.4% (10/14) vs. 78.6% (11/14); p = 0.678] and other safety-related outcomes. Additionally, while the overall survival and recurrence-free survival of patients with invasive cancer were not significantly different between these two groups, the T category and stage tended to be remarkably severe in the initial TP group. CONCLUSIONS: PSM analysis for prognostic factors showed that completion TP and initial TP have similar safety-related outcomes that can be used as a decision-making reference in the surgery of pancreatic tumors.

Inhibition of dopamine receptor D1 signaling promotes human bile duct cancer progression via WNT signaling.

Bile duct cancer (BDC) frequently invades the nerve fibers, making complete surgical resection difficult. A single tumor mass contains cells of variable malignancy and cell-differentiation states, with cancer stem cells (CSCs) considered responsible for poor clinical outcomes. This study aimed to investigate the contribution of autosynthesized dopamine to CSC-related properties in BDC. Sphere formation assays using 13 commercially available BDC cell lines demonstrated that blocking dopamine receptor D1 (DRD1) signaling promoted CSC-related anchorage-independent growth. Additionally, we newly established four new BDC patient-derived organoids (PDOs) and found that blocking DRD1 increased resistance to chemotherapy and enabled xenotransplantation in vivo. Single-cell analysis revealed that the BDC PDO cells varied in their cell-differentiation states and responses to dopamine signaling. Further, DRD1 inhibition increased WNT7B expression in cells with bile duct-like phenotype, and it induced proliferation of other cell types expressing Wnt receptors and stem cell-like signatures. Reagents that inhibited Wnt function canceled the effect of DRD1 inhibition and reduced cell proliferation in BDC PDOs. In summary, in BDCs, DRD1 is a crucial protein involved in autonomous CSC proliferation through the regulation of endogenous WNT7B. As such, inhibition of the DRD1 feedback signaling may be a potential treatment strategy for BDC.

Evaluation of the direction and extent of ice formation during cryoballoon ablation: an experimental study.

BACKGROUND: The distal hemisphere of a balloon is generally cooled during cryoapplication. However, a wide ablation area can be acquired after cryoballoon ablation. This study aimed to evaluate the extent of ice formation on two types of balloon surfaces through experimental and simulation studies. METHODS: A standard cryoballoon (SCB; Arctic Front Advance Pro, Medtronic) and novel cryoballoon (NCB; POLARx, Boston Scientific) were frozen for 240 s in 36 °C normal saline solution to observe ice formation on the balloon surface. Pieces of porcine tissue were placed between the upper and lower sides of the balloon, and the balloon was frozen in the horizontal direction for 240 s in 20 attempts (10 for SCB and NCB each). The measured areas of ice formation were evaluated and compared between the upper and lower sides of each balloon. RESULTS: Ice formation was greater on the lower side of the balloon than on the upper side. A larger area of ice formation in the tissue slab was observed on the lower side than on the upper side in both balloons, and the ice formation extended to the proximal hemisphere on the lower side of the balloon. The ice formation area in the NCB was significantly larger than that in SCB. CONCLUSIONS: Ice formation was significantly greater on the lower side of the cryoballoon than on the upper side and extended to the proximal hemisphere of the balloon, which might facilitate the acquisition of a wide ablation area on the left atrial posterior wall after cryoballoon ablation. Different ice formation after cryoballoon ablation Greater ice formation on the lower side of cryoballoon and an extensive ice formation in the proximal hemisphere, especially in novel cryoballoon.

Whole genome sequencing reveals the independent clonal origin of multifocal ileal neuroendocrine tumors.

BACKGROUND: Small intestinal neuroendocrine tumors (SI-NETs) are the most common neoplasms of the small bowel. The majority of tumors are located in the distal ileum with a high incidence of multiple synchronous primary tumors. Even though up to 50% of SI-NET patients are diagnosed with multifocal disease, the mechanisms underlying multiple synchronous lesions remain elusive. METHODS: We performed whole genome sequencing of 75 de-identified synchronous primary tumors, 15 metastases, and corresponding normal samples from 13 patients with multifocal ileal NETs to identify recurrent somatic genomic alterations, frequently affected signaling pathways, and shared mutation signatures among multifocal SI-NETs. Additionally, we carried out chromosome mapping of the most recurrent copy-number alterations identified to determine which parental allele had been affected in each tumor and assessed the clonal relationships of the tumors within each patient. RESULTS: Absence of shared somatic variation between the synchronous primary tumors within each patient was observed, indicating that these tumors develop independently. Although recurrent copy-number alterations were identified, additional chromosome mapping revealed that tumors from the same patient can gain or lose different parental alleles. In addition to the previously reported CDKN1B loss-of-function mutations, we observed potential loss-of-function gene alterations in TNRC6B, a candidate tumor suppressor gene in a small subset of ileal NETs. Furthermore, we show that multiple metastases in the same patient can originate from either one or several primary tumors. CONCLUSIONS: Our study demonstrates major genomic diversity among multifocal ileal NETs, highlighting the need to identify and remove all primary tumors, which have the potential to metastasize, and the need for optimized targeted treatments.

Nationwide registry for patients with neuroendocrine neoplasm of pancreas, gastrointestinal tract, lungs, bronchi, or thymus in Japan.

BACKGROUND: Neuroendocrine neoplasm (NEN) is a comparatively rare tumor that has been considered indolent. Due to these characteristics, detailed epidemiological data have not been analyzed in Japan. To elucidate the present status of NEN diagnosis and treatment in Japan, we started a registry cohort study in January 2015. METHODS: Patients pathologically diagnosed with NENs of the pancreas, gastrointestinal tract, lungs, bronchi, or thymus after January 2012 were enrolled in this registry after the date of ethics review committee approval in each hospital or institute. Follow-up was continued for enrolled patients. RESULTS: During 5 years of enrollment between January 2015 and December 2019, a total of 1526 participants from 63 departments were enrolled in this registry (mean, 305.2 participants/year), covering approximately 5.8% of the annual incidence of NENs in Japan. For pancreatic NEN, 41.9% of patients had metastasis and the dominant metastatic site was the liver, at twice the rate of lymph node metastasis in the current registry. In contrast, the frequency of lymph node metastasis from gastrointestinal (GI)-NEN was similar to that of the liver. The distribution of WHO 2019-based grades varied according to the primary site. Low-to-intermediate grade (G1-G2) was dominant for duodenal, jejunal/ileal, rectal, and pancreatic NENs, whereas high grade (G3 or NEC) was dominant for esophageal, stomach, and colon NENs. For PanNENs, G3 and NEC accounted only for 1.6% and 2.9%, respectively. CONCLUSIONS: These cohort data provide crucial information for clinical research to clarify the characteristics of NENs in Japan.

Preoperative risk stratification of lymph node metastasis for non-functional pancreatic neuroendocrine neoplasm: An international dual-institutional study.

BACKGROUND: /Objectives: Although the presence of lymph node metastasis (LNM) defines malignant potential, preoperative prediction of LNM has not been established for non-functional pancreatic neuroendocrine neoplasm (NF-PNEN). We sought to develop a prediction system using only preoperatively available factors that would stratify the risk of LNM for NF-PNEN. METHODS: We retrospectively reviewed patients who underwent R0/1 resection of NF-PNEN at Kyoto University (2007-2019) and the University of California, San Francisco (2010-2019). Risk stratification of LNM was developed using preoperative factors by the logistic regression analysis. Long-term outcomes were compared across the risk groups. RESULTS: A total of 131 patients were included in this study. Lymph nodes were pathologically examined in 116 patients, 23 (20%) of whom had LNM. Radiological tumor size [1.5-3.5 cm (odds ratio: 13.5, 95% confidence interval: 1.77-398) and >3.5 cm (72.4, 9.06-2257) against ≤1.5 cm], <50% cystic component (8.46 × 10^6, 1.68 × 10^106-), and dilatation of main pancreatic duct ≥5 mm (31.2, 3.94-702) were independently associated with LNM. When patients were classified as the low-risk (43 patients), intermediate-risk (44 patients), and high-risk groups (29 patients), proportions of LNM differed significantly across the groups (0%, 14%, and 59%, respectively). Recurrence-free survival (RFS) of the low- and intermediate-risk groups were significantly better than that of the high-risk group (5-year RFS rates of 92.2%, 85.4%, and 47.1%, respectively). CONCLUSIONS: The prediction system using preoperative radiological factors stratifies the risk of LNM for NF-PNEN. This stratification helps to predict malignant potential and determine the surgical procedure and necessity of regional lymphadenectomy.

Sinusoidal Obstruction Syndrome Promotes Liver Metastatic Seeding of Colorectal Cancer Cells in a Rat Model.

BACKGROUND/AIM: Sinusoidal obstruction syndrome (SOS) after neoadjuvant chemotherapy with oxaliplatin for colorectal liver metastases (CRLM) has been reported to lead to early recurrence. This study investigated the effects of SOS on the development of CRLM in a rat model. MATERIALS AND METHODS: RCN-H4 cells were injected into the spleen or liver of ten monocrotaline-treated (SOS group) and ten untreated (control group) rats. The number and size of liver tumors were compared between the groups. RESULTS: The number of liver tumors in the splenic RCN-H4 injection model was significantly higher in the SOS group than in the control group (332±213 vs. 16±5, p=0.029); however, the largest tumor diameter in the hepatic model was similar between groups (6.2±1.8 vs. 6.4±2.4 mm, p=0.87). CONCLUSION: SOS promotes CRLM development by splenic RCN-H4 cell injection. This might be due to the higher incidence of cancer cell implantation into the liver.

A subcentimeter duodenal neuroendocrine neoplasm with a liver metastasis upgraded to G3: a case report.

BACKGROUND: Although duodenal neuroendocrine neoplasms (DuNENs) usually have indolent phenotypes, some DuNENs exhibit aggressive clinical manifestations. Tumor size > 1 cm, lymph node metastasis, and high grade have been associated with poor prognosis. However, preoperative risk evaluation is often difficult, because Ki-67 index on biopsy is frequently underestimated due to the intratumor heterogeneity. Here, we present a case of a subcentimeter DuNEN with a low Ki-67 index on endoscopic biopsy, who developed lymph node metastasis and high-grade liver metastasis. CASE PRESENTATION: The patient was a 52-year-old female who presented an epigastric pain. Esophagogastroduodenoscopy revealed a duodenal submucosal lesion with a size of 8 mm. The endoscopic biopsy showed DuNEN with a Ki-67 index of 3.3% (G2 categorized by the World Health Organization 2019 classification). We performed an open partial duodenectomy with adjacent lymph node dissection. Pathological examination of the resected specimens revealed a Ki-67 index of 13.5% (G2) in the "hot spot" and lymph node metastasis. A hepatic low-density area detected on preoperative contrast-enhanced computed tomography appeared to be a liver metastasis on postoperative gadoxetic acid-enhanced magnetic resonance imaging. Subsequently, we performed a laparoscopic partial hepatectomy. Pathological examination of the liver specimen showed a metastatic neuroendocrine tumor with a Ki-67 index of 27.5% (NET-G3). The patient has been alive for 14 months since the hepatectomy. CONCLUSIONS: This case shows the possibility of high malignant potential of DuNEN even if the primary lesion is < 1 cm and has a low Ki-67 index on biopsy.

Chloroquine induces apoptosis in pancreatic neuroendocrine neoplasms via endoplasmic reticulum stress.

Although pancreatic neuroendocrine neoplasms (PanNENs) are generally indolent, patients with distant metastasis have a dismal prognosis. Recently, the autophagy inhibitor chloroquine (CQ) has been shown to suppress the tumour growth of PanNENs, but the detailed mechanisms have not been elucidated. Furthermore, these results were obtained from poorly differentiated cell lines rather than well-differentiated cell lines, which is the most prevalent type in this tumour. To explore the mechanism and efficacy of CQ on PanNENs, we applied CQ to cell lines and evaluated the resulting apoptosis and endoplasmic reticulum (ER) stress. CQ treatment induced ER stress, and an unfolded protein response was activated through the PERK-eIF2α-ATF4 pathway, resulting in the expression of the pro-apoptotic protein C/EBP homologous protein (CHOP), which reflects ER-stress-mediated apoptotic cell death. Furthermore, hydroxychloroquine (HCQ) was effective in Men1 heterozygous-deficient (Men1+/ΔN3-8) mice, a mouse PanNEN model that is considered to correspond to human low-grade PanNEN. HCQ administration decreased tumour size in Men1+/ΔN3-8 mice. In the HCQ group, histological analyses revealed that proliferative activity was unchanged, but apoptosis was accelerated, accompanied by CHOP expression. These results suggest that autophagy inhibition by CQ/HCQ could be used for the treatment of PanNEN, including the well-differentiated type.

Awareness of a mesenteric mass as a common manifestation of ileal neuroendocrine tumor.

Omori et al. reported a case of multiple liver metastases originating from synchronous double cancer of "primary mesenteric neuroendocrine tumor" and rectal cancer. However, the "primary mesenteric neuroendocrine tumor" might be a misrecognition of mesenteric metastasis from ileal neuroendocrine tumor. Ileal neuroendocrine tumor is extremely rare in Japan. Herein, we aim to describe the characteristics of ileal neuroendocrine tumor and mesenteric mass as its common manifestation in reference to their reported case.