Faculty Bibliography

BACKGROUND:The new T1 pancreatic cancer by the eighth edition of the AJCC staging system discards the concept of "extension beyond the pancreas" and focuses on size only. Furthermore, the new T1 is divided into T1a, T1b, and T1c based on size. The evidence pertaining to these changes has not been evaluated. This is to evaluate the feasibility of the new T1 definition in the pancreas head cancer cohort. METHODS:Data from 540 patients with T1 pancreatic ductal adenocarcinoma as defined by the eighth edition were collected from Korea, Japan, and the USA. Invasive IPMNs were excluded. Survival analyses were performed. RESULTS:Of the 540 patients, 181 patients were T1 according to the seventh edition and 359 were down-staged to T1 from the former T3 because the concept of "extension beyond the pancreas" was discarded. The 5-year survival rate and the median survival of T1 patients were 30.6% and 27 months, respectively. Comparing tumors that extend beyond the pancreas (new T1) and those confined within the pancreas (original T1), the latter showed significantly longer median survival (43 vs. 24 months, p < 0.001). In terms of T1a/b/c, there were no significant differences in survival. Using MaxStat, subdividing into two groups using 1.1 cm as the cut-off value, yielded significantly discrete prognostic groups (p < 0.001). CONCLUSION:The new T1 definition may be more practical, but the implications of the concept of "extension beyond the pancreas" should be re-investigated. Further, the subcategorization of T1a/b/c may not be adequate and may require revision or deletion.

BACKGROUND:Patients with high body mass index are associated with a higher risk of complications after open pancreatectomy. We aimed to investigate the perioperative outcome for patients with high body mass index after robotic pancreatectomy. METHODS:This is a retrospective, propensity-score matched cohort analysis. From our prospectively maintained database, we identified consecutive patients with body mass index >25 who underwent robotic pancreatectomy between January 2016 and December 2018. Propensity score matching with open pancreatectomy was applied in 1:2 fashion based on age, gender, American Society of Anesthesiologists classification, surgery type, histology, neoadjuvant therapy, and body mass index during the same study period. RESULTS:A total of 127 patients were included. The mean age for all patients was 61.7 ± 12.8 years and 65 (51.2%) were male. Median body mass index was 29.9 (interquartile range, 27.0-31.8) for both groups. Propensity score matching provided equally distributed general demographic and clinicopathological factors. Robotic pancreatectomy was associated with decreased blood loss (100 mL vs 300 mL, P < .001) and shorter hospital stay (7 vs 9 days, P = .019). CONCLUSION:Robotic pancreatectomy is associated with decreased blood loss and shorter length of hospital stay in overweight patients. Robotic approach may help alleviate morbidity in overweight patients undergoing pancreatectomy.

BACKGROUND:The objective of this study was to validate and update the Amsterdam prediction model including tumor grade, lymph node ratio, margin status and adjuvant therapy, for prediction of overall survival (OS) after pancreatoduodenectomy for pancreatic cancer. METHODS:We included consecutive patients who underwent pancreatoduodenectomy for pancreatic cancer between 2000 and 2017 at 11 tertiary centers in 8 countries (USA, UK, Germany, Italy, Sweden, the Netherlands, Korea, Australia). Model performance for prediction of OS was evaluated by calibration statistics and Uno's C-statistic for discrimination. Validation followed the TRIPOD statement. RESULTS:Overall, 3081 patients (53% male, median age 66 years) were included with a median OS of 24 months, of whom 38% had N2 disease and 77% received adjuvant chemotherapy. Predictions of 3-year OS were fairly similar to observed OS with a calibration slope of 0.72. Statistical updating of the model resulted in an increase of the C-statistic from 0.63 to 0.65 (95% CI 0.64-0.65), ranging from 0.62 to 0.67 across different countries. The area under the curve for the prediction of 3-year OS was 0.71 after updating. Median OS was 36, 25 and 15 months for the low, intermediate and high risk group, respectively (P < 0.001). CONCLUSIONS:This large international study validated and updated the Amsterdam model for survival prediction after pancreatoduodenectomy for pancreatic cancer. The model incorporates readily available variables with a fairly accurate model performance and robustness across different countries, while novel markers may be added in the future. The risk groups and web-based calculator www.pancreascalculator.com may facilitate use in daily practice and future trials.

Recent studies considered surgery as a treatment option for patients with pancreatic ductal adenocarcinoma (PDAC) and synchronous liver metastases. The aim of this study was to evaluate systematically the literature on the role of surgical resection in this setting as an upfront procedure or following primary chemotherapy. A systematic search was performed of PubMed, Embase and the Cochrane Library in accordance with PRISMA guidelines. Only studies that included patients with synchronous liver metastases published in the era of multiagent chemotherapy (after 2011) were considered, excluding those with lung/peritoneal metastases or metachronous liver metastases. Median overall survival (OS) was the primary outcome. Six studies with 204 patients were analyzed. 63% of patients underwent upfront pancreatic and liver resection, 35% had surgery after primary chemotherapy with strict selection criteria and 2% had an inverse approach (liver surgery first). 38 patients (18.5%) did not undergo any liver resection since metastases disappeared after chemotherapy. Postoperative mortality was low (< 2%). Median OS ranged from 7.6 to 14.5 months after upfront pancreatic/liver resection and from 34 to 56 months in those undergoing preoperative treatment. This systematic review suggests that surgical resection of pancreatic cancer with synchronous liver oligometastases is safe, and it can be associated with improved survival, providing a careful selection of patients after primary chemotherapy.

We report a sensitive PCR-based assay called Repetitive Element AneupLoidy Sequencing System (RealSeqS) that can detect aneuploidy in samples containing as little as 3 pg of DNA. Using a single primer pair, we amplified ∼350,000 amplicons distributed throughout the genome. Aneuploidy was detected in 49% of liquid biopsies from a total of 883 nonmetastatic, clinically detected cancers of the colorectum, esophagus, liver, lung, ovary, pancreas, breast, or stomach. Combining aneuploidy with somatic mutation detection and eight standard protein biomarkers yielded a median sensitivity of 80% in these eight cancer types, while only 1% of 812 healthy controls scored positive.

PURPOSE/OBJECTIVE:We assessed the feasibility and safety of placing a radiopaque hydrogel in the pancreaticoduodenal groove via endoscopic ultrasound guidance in patients with borderline resectable/locally advanced pancreatic cancer (BR/LAPC). METHODS AND MATERIALS/METHODS:Hydrogel injections were done at time of fiducial placement to form blebs in the pancreaticoduodenal groove. Patients subsequently underwent simulation computed tomography (sim-CT) followed by hypofractionated stereotactic body radiotherapy (SBRT; 33 Gy in 5 fractions). Four to 8 weeks after SBRT, patients underwent CT re-evaluation for surgical candidacy and assessment of hydrogel location and size. Hydrogel placement was considered successful if identified in the pancreaticoduodenal groove on sim-CT scan. Stability was evaluated using equivalence testing analyses, with a null hypothesis of the presence of a ≥20% mean percentage change in volume and ≥2 mm change in the median and mean interbleb surface distance with a P value <.05 required to reject the null hypothesis and conclude equivalence. For patients undergoing pancreaticoduodenectomy, hydrogel sites were histologically examined for location and local inflammatory reactions. RESULTS:Hydrogel placement was successful in 6 of the 6 evaluable patients. The average changes in median and mean interbleb distances were -0.43 mm and -0.35 mm, respectively, with P < .05. The average change in volume from sim-CT to post-SBRT CT was -1.0%, with P < .05. One patient experienced grade 3 nausea after fiducial/hydrogel placement, with no other adverse events to date. CONCLUSIONS:These data demonstrate feasibility and safety of injecting a hydrogel marker in the pancreaticoduodenal groove in patients with BR/LAPC and set the stage for a follow-up clinical trial to place hydrogel as a spacer between the pancreatic tumor and dose-limiting, radiosensitive duodenum.

Circulating tumor DNA (ctDNA) measurements can be used to estimate tumor burden, but avoiding false-positive results is challenging. Herein, digital next-generation sequencing (NGS) is evaluated as a ctDNA detection method. Plasma KRAS and GNAS hotspot mutation levels were measured in 140 subjects, including 67 with pancreatic ductal adenocarcinoma and 73 healthy and disease controls. To limit chemical modifications of DNA that yield false-positive mutation calls, plasma DNA was enzymatically pretreated, after which DNA was aliquoted for digital detection of mutations (up to 384 aliquots/sample) by PCR and NGS. A digital NGS score of two SDs above the mean in controls was considered positive. Thirty-seven percent of patients with pancreatic cancer, including 31% of patients with stages I/II disease, had positive KRAS codon 12 ctDNA scores; only one patient had a positive GNAS mutation score. Two disease control patients had positive ctDNA scores. Low-normal-range digital NGS scores at mutation hotspots were found at similar levels in healthy and disease controls, usually at sites of cytosine deamination, and were likely the result of chemical modification of plasma DNA and NGS error rather than true mutations. Digital NGS detects mutated ctDNA in patients with pancreatic cancer with similar yield to other methods. Detection of low-level, true-positive ctDNA is limited by frequent low-level detection of false-positive mutation calls in plasma DNA from controls.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy characterized by extensive local invasion and systemic spread. In this study, we employed a three-dimensional organoid model of human pancreatic cancer to characterize the molecular alterations critical for invasion. Time-lapse microscopy was used to observe invasion in organoids from 25 surgically resected human PDAC samples in collagen I. Subsequent lentiviral modification and small-molecule inhibitors were used to investigate the molecular programs underlying invasion in PDAC organoids. When cultured in collagen I, PDAC organoids exhibited two distinct, morphologically defined invasive phenotypes, mesenchymal and collective. Each individual PDAC gave rise to organoids with a predominant phenotype, and PDAC that generated organoids with predominantly mesenchymal invasion showed a worse prognosis. Collective invasion predominated in organoids from cancers with somatic mutations in the driver gene SMAD4 (or its signaling partner TGFBR2). Reexpression of SMAD4 abrogated the collective invasion phenotype in SMAD4-mutant PDAC organoids, indicating that SMAD4 loss is required for collective invasion in PDAC organoids. Surprisingly, invasion in passaged SMAD4-mutant PDAC organoids required exogenous TGFβ, suggesting that invasion in SMAD4-mutant organoids is mediated through noncanonical TGFβ signaling. The Rho-like GTPases RAC1 and CDC42 acted as potential mediators of TGFβ-stimulated invasion in SMAD4-mutant PDAC organoids, as inhibition of these GTPases suppressed collective invasion in our model. These data suggest that PDAC utilizes different invasion programs depending on SMAD4 status, with collective invasion uniquely present in PDAC with SMAD4 loss. SIGNIFICANCE: Organoid models of PDAC highlight the importance of SMAD4 loss in invasion, demonstrating that invasion programs in SMAD4-mutant and SMAD4 wild-type tumors are different in both morphology and molecular mechanism.

BACKGROUND AND AIMS/OBJECTIVE:Single-cell next-generation sequencing (scNGS) technology has been widely used in genomic profiling, which relies on whole-genome amplification (WGA). However, WGA introduces errors and is especially less accurate when applied to single nucleotide variant (SNV) analysis. Targeted scNGS for SNV without WGA has not been described. We aimed to develop a method to detect circulating tumor cells (CTCs) with DNA SNVs. METHODS:We tested this targeted scNGS method with three driver mutant genes (KRAS/TP53/SMAD4) on one pancreatic cancer cell line AsPC-1 and then applied it to patients with metastatic PDAC for the validation. RESULTS:All single-cell of AsPC-1 and spiked-in AsPC-1 cells in healthy donor blood, which were isolated by the filtration with size or by flow cytometry, were detected by targeted scNGS method. All blood samples from six patients with metastatic PDAC, for the validation of target scNGS method, showed CTCs with SNVs of KRAS/TP53/SMAD4 and the positive confirmation of immunofluorescent stainings with Pan-CK/Vimentin/CD45. Four patients with early stage disease, one patient with benign pancreatic cyst and a healthy control sample all showed concordant results between targeted scNGS and CTC enumeration. CONCLUSIONS:The novel technique of targeted scNGS for SNV analysis, without pre-amplification, is a promising method for identifying and characterizing circulating tumor cells.