Adjuvant chemotherapy for adenocarcinoma arising from intraductal papillary mucinous neoplasia: multicentre ADENO-IPMN study

BACKGROUND

The clinical impact of adjuvant chemotherapy after resection for adenocarcinoma arising from intraductal papillary mucinous neoplasia is unclear. The aim of this study was to identify factors related to receipt of adjuvant chemotherapy and its impact on recurrence and survival.

METHODS

This was a multicentre retrospective study of patients undergoing pancreatic resection for adenocarcinoma arising from intraductal papillary mucinous neoplasia between January 2010 and December 2020 at 18 centres. Recurrence and survival outcomes for patients who did and did not receive adjuvant chemotherapy were compared using propensity score matching.

RESULTS

Of 459 patients who underwent pancreatic resection, 275 (59.9%) received adjuvant chemotherapy (gemcitabine 51.3%, gemcitabine-capecitabine 21.8%, FOLFIRINOX 8.0%, other 18.9%). Median follow-up was 78 months. The overall recurrence rate was 45.5% and the median time to recurrence was 33 months. In univariable analysis in the matched cohort, adjuvant chemotherapy was not associated with reduced overall (P = 0.713), locoregional (P = 0.283) or systemic (P = 0.592) recurrence, disease-free survival (P = 0.284) or overall survival (P = 0.455). Adjuvant chemotherapy was not associated with reduced site-specific recurrence. In multivariable analysis, there was no association between adjuvant chemotherapy and overall recurrence (HR 0.89, 95% c.i. 0.57 to 1.40), disease-free survival (HR 0.86, 0.59 to 1.30) or overall survival (HR 0.77, 0.50 to 1.20). Adjuvant chemotherapy was not associated with reduced recurrence in any high-risk subgroup (for example, lymph node-positive, higher AJCC stage, poor differentiation). No particular chemotherapy regimen resulted in superior outcomes.

CONCLUSION

Chemotherapy following resection of adenocarcinoma arising from intraductal papillary mucinous neoplasia does not appear to influence recurrence rates, recurrence patterns or survival.

Long-term Outcomes following Resection of Adenocarcinoma Arising from Intraductal Papillary Mucinous Neoplasm (A-IPMN) versus Pancreatic Ductal Adenocarcinoma (PDAC): A Propensity-score Matched Analysis

OBJECTIVE

The aim of the present study was to compare long-term post-resection oncological outcomes between A-IPMN and PDAC.

SUMMARY BACKGROUND DATA

Knowledge of long term oncological outcomes (e.g recurrence and survival data) comparing between adenocarcinoma arising from intraductal papillary mucinous neoplasms (A-IPMN) and pancreatic ductal adenocarcinoma (PDAC) is scarce.

METHODS

Patients undergoing pancreatic resection (2010-2020) for A-IPMN were identified retrospectively from 18 academic pancreatic centres and compared with PDAC patients from the same time-period. Propensity-score matching (PSM) was performed and survival and recurrence were compared between A-IPMN and PDAC.

RESULTS

459 A-IPMN patients (median age,70; M:F,250:209) were compared with 476 PDAC patients (median age,69; M:F,262:214). A-IPMN patients had lower T-stage, lymphovascular invasion (51.4%vs. 75.6%), perineural invasion (55.8%vs. 71.2%), lymph node positivity (47.3vs. 72.3%) and R1 resection (38.6%vs. 56.3%) compared to PDAC(P<0.001). The median survival and time-to-recurrence for A-IPMN versus PDAC were 39.0 versus19.5months (P<0.001) and 33.1 versus 14.8months (P<0.001), respectively (median follow-up,78 vs.73 months). Ten-year overall survival for A-IPMN was 34.6%(27/78) and PDAC was 9%(6/67). A-IPMN had higher rates of peritoneal (23.0 vs. 9.1%, P<0.001) and lung recurrence (27.8% vs. 15.6%, P<0.001) but lower rates of locoregional recurrence (39.7% vs. 57.8%; P<0.001). Matched analysis demonstrated inferior overall survival (P=0.005), inferior disease-free survival (P=0.003) and higher locoregional recurrence (P<0.001) in PDAC compared to A-IPMN but no significant difference in systemic recurrence rates (P=0.695).

CONCLUSIONS

PDACs have inferior survival and higher recurrence rates compared to A-IPMN in matched cohorts. Locoregional recurrence is higher in PDAC but systemic recurrence rates are comparable and constituted by their own distinctive site-specific recurrence patterns.

Clinical usefulness of routinely performed drain fluid cultures after pancreaticoduodenectomy. A new ally to predict patients' outcomes?

BACKGROUND

Previous studies showed that bacterial contamination of surgical drains was associated with higher morbidity and mortality following pancreaticoduodenectomy (PD). However, there is still no agreement on the routine use of fluid drainage cultures in the management of patients underwent PD. Therefore, we aimed to clarify the role of surgical drain bacterial contamination in predicting patients' postoperative course.

METHOD

Single-centre study including patients underwent PD at Humanitas Research Hospital (2010-2021). Preoperative, intraoperative and postoperative data were collected. Routinely performed fluid drain cultures on postoperative day (POD) 5 were analyzed and compared among patients throughout the cohort.

RESULTS

A total of 825 patients were analyzed. Bacterial contamination of surgical drains was observed in 420 (50.9 %) patients and it was found to be associated with a higher rate of B/C grade pancreatic fistula (POPF) (P < 0.001), Clavien-Dindo≥3 (P < 0.001), 30-day mortality (P = 0.011), wound infection (P < 0.001), relaparotomies (P = 0.003) and greater length of hospital stay (LOS) (P < 0.001). Also, E. coli surgical drain contamination was demonstrated to double the risk of B/C grade POPF development (OR = 1.628, 95 % IC = 1.009-2.625, P = 0.046). Finally, preoperative biliary drainage (OR = 2.474, 95 % IC = 1.855-3.298, P < 0.001), age ≥75 years old (OR = 1.492, 95 % IC = 1.077-2.067, P = 0.016) and isolated Roux-en-Y pancreaticojejunostomy (OR = 1.639, 95 % IC = 1.229-2.188, P < 0.001) were identified as risk factors for surgical drains bacterial contamination.

CONCLUSION

Bacterial contamination of surgical drains predicts the development of B/C grade POPF and other major complications after PD. Therefore, we suggest the routine use of fluid drain cultures following PD.

The role of intraoperative pancreatoscopy in the surgical management of intraductal papillary mucinous neoplasms of the pancreas: a systematic scoping review

BACKGROUND

The type and the extent of surgery is still debatable for intraductal papillary mucinous neoplasm (IPMN). Intraoperative pancreatoscopy (IOP) allows the visualization of the main pancreatic duct (MPD) in its entire length and could help determine the extent of MPD involvement and the type and extent of pancreatic resection. However, current guidelines do not advise its routine use as there is a lack of evidence supporting its safety and feasibility. The present study aims to perform a scoping review of published evidence on the safety and feasibility of IOP in IPMN surgical management.

METHODS

We systematically searched PubMed, Cochrane, Medline and EMbase to identify studies reporting the use of IOP in IPMN surgical management. The research was completed in June 2023. Data extracted included patient selection criteria, demographics, safety of the procedure, intraoperative findings, impact on surgical strategy, histology results and postoperative outcomes.

RESULTS

Four retrospective and one prospective study were included in this scoping review. A total of 142 patients had IOP. The selection criteria for inclusion were heterogenous, with one out of five studies including branch duct (BD), main duct (MD) and mixed type IPMN. Indications for IOP and surgical resection were only reported in two studies. A median of seven outcomes (range 5-8) was described, including the type of surgical resection, additional lesions and change of surgical plan, and complications after IOP. IOP showed additional lesions in 48 patients (34%) and a change of surgical plan in 48(34%). No IOP-related complications were reported.

CONCLUSIONS

This scoping review suggests IOP is safe and identifies additional lesions impacting the surgical strategy for IPMN. However, the included studies were small and heterogeneous regarding IPMN definition and indications for surgery and IOP. There is a need for a large multi-centre prospective study to determine the role of IOP and its impact on surgical strategy for IPMN.

Anticoagulation after pancreatic surgery with venous resection (TIGRESS): What should we do? Results from an international survey

Backgrounds/Aims

Patients who undergo pancreatic surgery with venous resection have high rates of morbidity/mortality. Also, they are high-risk for postoperative venous thromboembolism. Whether this group should be routinely anticoagulated is unknown. This study aimed to establish current anticoagulation practices.

Methods

A survey (https://form.jotform.com/220242489107048) was sent out to pancreatic surgeons. Questions covered center volume, venous resection/reconstruction techniques and anticoagulation policies.

Results

Sixty-five centers from 17 countries responded. Following a "side-bite" venous resection with a patch repair, 40% used an autologous vein patch, 27% used peritoneum, and 27% used a bovine patch. After formally resecting a segment of vein, 17% of centers used an interposition graft (IG). Left renal vein (41%) and polytetrafluoroethylene (73%) grafts were the most commonly used autologous and prosthetic IGs, respectively. Following a prosthetic IG, an autologous IG, and a "side-bite" resection, 59%, 28%, and 19% of centers provided therapeutic anticoagulation, respectively (66% used low molecular-weight heparin). The duration of therapy provided varied from inpatient stay only (14%) to six months (32%).

Conclusions

Our global survey indicates that anticoagulation practices are highly variable. Centers do not agree on when to anticoagulate, how to anticoagulate, or the duration of therapy. A robust trial is required to provide clarity.

Risk of Recurrence after Surgical Resection for Adenocarcinoma Arising from Intraductal Papillary Mucinous Neoplasia (IPMN) with Patterns of Distribution and Treatment: An International, Multicentre, Observational Study

OBJECTIVE

This international multicentre cohort study aims to identify recurrence patterns and treatment of first and second recurrence in a large cohort of patients after pancreatic resection for adenocarcinoma arising from IPMN.

SUMMARY BACKGROUND DATA

Recurrence patterns and treatment of recurrence post resection of adenocarcinoma arising from IPMN are poorly explored.

METHOD

Patients undergoing pancreatic resection for adenocarcinoma from IPMN between January 2010 to December 2020 at 18 pancreatic centres were identified. Survival analysis was performed by the Kaplan-Meier log rank test and multivariable logistic regression by Cox-Proportional Hazards modelling. Endpoints were recurrence (time-to, location, and pattern of recurrence) and survival (overall survival and adjusted for treatment provided).

RESULTS

Four hundred and fifty-nine patients were included (median, 70 y; IQR, 64-76; male, 54 percent) with a median follow-up of 26.3 months (IQR, 13.0-48.1 mo). Recurrence occurred in 209 patients (45.5 percent; median time to recurrence, 32.8 months, early recurrence [within 1 y], 23.2 percent). Eighty-three (18.1 percent) patients experienced a local regional recurrence and 164 (35.7 percent) patients experienced distant recurrence. Adjuvant chemotherapy was not associated with reduction in recurrence (HR 1.09;P=0.669) One hundred and twenty patients with recurrence received further treatment. The median survival with and without additional treatment was 27.0 and 14.6 months (P<0.001), with no significant difference between treatment modalities. There was no significant difference in survival between location of recurrence (P=0.401).

CONCLUSION

Recurrence after pancreatic resection for adenocarcinoma arising from IPMN is frequent with a quarter of patients recurring within 12 months. Treatment of recurrence is associated with improved overall survival and should be considered.

Successful Development of a Natural Language Processing Algorithm for Pancreatic Neoplasms and Associated Histologic Features

OBJECTIVES

Natural language processing (NLP) algorithms can interpret unstructured text for commonly used terms and phrases. Pancreatic pathologies are diverse and include benign and malignant entities with associated histologic features. Creating a pancreas NLP algorithm can aid in electronic health record coding as well as large database creation and curation.

METHODS

Text-based pancreatic anatomic and cytopathologic reports for pancreatic cancer, pancreatic ductal adenocarcinoma, neuroendocrine tumor, intraductal papillary neoplasm, tumor dysplasia, and suspicious findings were collected. This dataset was split 80/20 for model training and development. A separate set was held out for testing purposes. We trained using convolutional neural network to predict each heading.

RESULTS

Over 14,000 reports were obtained from the Mass General Brigham Healthcare System electronic record. Of these, 1252 reports were used for algorithm development. Final accuracy and F1 scores relative to the test set ranged from 95% and 98% for each queried pathology. To understand the dependence of our results to training set size, we also generated learning curves. Scoring metrics improved as more reports were submitted for training; however, some queries had high index performance.

CONCLUSIONS

Natural language processing algorithms can be used for pancreatic pathologies. Increased training volume, nonoverlapping terminology, and conserved text structure improve NLP algorithm performance.

Progression from biochemical leak to pancreatic fistula after distal pancreatectomy. Don't cry over spilt amylase

BACKGROUND

Postoperative pancreatic fistula (POPF) is a frequent complication after distal pancreatectomy (DP), but its upgrading from biochemical leak (BL) still represents an unexplored phenomenon. This study aims at identifying risk factors of the clinical evolution from BL to grade-B POPF after DP.

METHODS

Patients who underwent DP between 2015 and 2019 and who developed either BL (n = 89,56%) or BL upgraded to late B fistula (LB) after postoperative day 5 (n = 71,44%) were included. Preoperative, surgical, postoperative predictors were compared between the two groups.

RESULTS

Patients with LB were significantly older (61 vs 56 years, P < 0.025) and received neoadjuvant chemotherapy more frequently (22.5% vs 8.5%,P = 0.017). Extended lymphadenectomy (52.8% vs 31.0%,P = 0.006), longer operative times (OT) (307 vs 250 min,P = 0.002), greater estimated blood loss (250 vs 150 ml, P = 0.021), and the appearance of purulent fluid in surgical drains (58.4% vs 21.1%; P < 0.001) were more frequently observed in LB group. Only purulent fluid in surgical drains and longer OT were confirmed as independent predictors of BL clinical progression.

CONCLUSIONS

Purulent fluid from surgical drains should be suspicious of BL upgrading. Frail patients undergoing longer interventions may represent key targets of mitigation strategies to minimize the magnitude of an incipient fistula and its increase in morbidity.

Single-nucleus and spatial transcriptome profiling of pancreatic cancer identifies multicellular dynamics associated with neoadjuvant treatment

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal and treatment-refractory cancer. Molecular stratification in pancreatic cancer remains rudimentary and does not yet inform clinical management or therapeutic development. Here, we construct a high-resolution molecular landscape of the cellular subtypes and spatial communities that compose PDAC using single-nucleus RNA sequencing and whole-transcriptome digital spatial profiling (DSP) of 43 primary PDAC tumor specimens that either received neoadjuvant therapy or were treatment naive. We uncovered recurrent expression programs across malignant cells and fibroblasts, including a newly identified neural-like progenitor malignant cell program that was enriched after chemotherapy and radiotherapy and associated with poor prognosis in independent cohorts. Integrating spatial and cellular profiles revealed three multicellular communities with distinct contributions from malignant, fibroblast and immune subtypes: classical, squamoid-basaloid and treatment enriched. Our refined molecular and cellular taxonomy can provide a framework for stratification in clinical trials and serve as a roadmap for therapeutic targeting of specific cellular phenotypes and multicellular interactions.

Abstract 94: Multi-compartment reprogramming and spatially-resolved interactions in frozen pancreatic cancer with and without neoadjuvant chemotherapy and radiotherapy at single-cell resolution

A molecular classification of pancreatic ductal adenocarcinoma (PDAC) that informs clinical management remains elusive. Previously identified bulk expression subtypes in the untreated setting were influenced by contaminating stroma whereas single cell RNA-seq (scRNA-seq) of fresh tumors under-represented key cell types. Two consensus subtypes have arisen from these prior efforts: (1) classical-like, and (2) basal-like. Basal-like tumors were associated with worse survival in the metastatic setting but attempts to refine this binary classification have failed to further stratify patient survival. Here, we developed a robust single-nucleus RNA-seq (snRNA-seq) technique for banked frozen PDAC specimens and studied a cohort of untreated resected primary tumors (n ~ 20). Gene expression programs learned across malignant cell and cancer-associated fibroblast (CAF) profiles uncovered a clinically-relevant molecular taxonomy with improved prognostic stratification compared to prior classifications. Digital spatial profiling revealed an association between malignant cells expressing basal-like programs and greater immune infiltration with relatively fewer macrophages, whereas those exhibiting classical-like programs were linked to inflammatory CAFs and macrophage-predominant microniches. Recent clinical trials have supported the increasing adoption of neoadjuvant therapy to aggressively address the risk of micro-metastatic spread and to circumvent concerns of treatment tolerance in the postoperative setting. There is an urgent need to understand how preoperative treatment impacts residual tumor cells and their interactions with other cell types in the tumor microenvironment to identify additional therapeutic vulnerabilities that can be exploited. Towards this end, we performed snRNA-seq on an unmatched cohort of neoadjuvant-treated resected primary tumors (n ~ 25) with most cases involving FOLFIRINOX chemotherapy followed by chemoradiation. Remarkably, the quality of single-nucleus mRNA profiles was comparable between heavily pre-treated and untreated specimens. We identified differentially expressed genes between treated and untreated samples to infer cell-type specific reprogramming in the residual tumor. This analysis revealed that in the neoadjuvant treatment context, there was lower expression of classical-like phenotypes in malignant cells in favor of basal-like phenotypes associated with TNF-NFkB and interferon signaling as well as the presence of novel acinar and neuroendocrine classical-like states. Our refined molecular taxonomy and spatial resolution may help advance precision oncology in PDAC through informative stratification in clinical trials and insights into compartment-specific therapies.

Citation Format: William L. Hwang, Karthik A. Jagadeesh, Jimmy A. Guo, Hannah I. Hoffman, Payman Yadollahpour, Jason Reeves, Eugene Drokhlyansky, Nicholas Van Wittenberghe, Samouil Farhi, Denis Schapiro, George Eng, Jason M. Schenkel, William A. Freed-Pastor, Orr Ashenberg, Clifton Rodrigues, Domenic Abbondanza, Toni Delorey, Devan Phillips, Jorge Roldan, Debora Ciprani, Marina Kern, Jaimie L. Barth, Daniel R. Zollinger, Kit Fuhrman, Robin Fropf, Joseph Beechem, Colin Weekes, Cristina R. Ferrone, Jennifer Y. Wo, Theodore S. Hong, Orit Rozenblatt-Rosen, Andrew J. Aguirre, Mari Mino-Kenudson, Carlos Fernandez-del- Castillo, Andrew S. Liss, David T. Ting, Tyler Jacks, Aviv Regev. Multi-compartment reprogramming and spatially-resolved interactions in frozen pancreatic cancer with and without neoadjuvant chemotherapy and radiotherapy at single-cell resolution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 94.

Influence of Klebsiella pneumoniae and quinolone treatment on prognosis in patients with pancreatic cancer

BACKGROUND

An increasing body of evidence suggests that microbiota may promote progression of pancreatic ductal adenocarcinoma (PDAC). It was hypothesized that gammaproteobacteria (such as Klebsiella pneumoniae) influence survival in PDAC, and that quinolone treatment may attenuate this effect.

METHODS

This was a retrospective study of patients from the Massachusetts General Hospital (USA) and Ludwig-Maximilians-University (Germany) who underwent preoperative treatment and pancreatoduodenectomy for locally advanced or borderline resectable PDAC between January 2007 and December 2017, and for whom a bile culture was available. Associations between tumour characteristics, survival data, antibiotic use and results of intraoperative bile cultures were investigated. Survival was analysed using Kaplan-Meier curves and Cox regression analysis.

RESULTS

Analysis of a total of 211 patients revealed that an increasing number of pathogen species found in intraoperative bile cultures was associated with a decrease in progression-free survival (PFS) (-1·9 (95 per cent c.i. -3·3 to -0·5) months per species; P = 0·009). Adjuvant treatment with gemcitabine improved PFS in patients who were negative for K. pneumoniae (26·2 versus 15·3 months; P = 0·039), but not in those who tested positive (19·5 versus 13·2 months; P = 0·137). Quinolone treatment was associated with improved median overall survival (OS) independent of K. pneumoniae status (48·8 versus 26·2 months; P = 0·006) and among those who tested positive for K. pneumoniae (median not reached versus 18·8 months; P = 0·028). Patients with quinolone-resistant K. pneumoniae had shorter PFS than those with quinolone-sensitive K. pneumoniae (9·1 versus 18·8 months; P = 0·001).

CONCLUSION

K. pneumoniae may promote chemoresistance to adjuvant gemcitabine, and quinolone treatment is associated with improved survival.

Pancreatic surgery is a safe teaching model for tutoring residents in the setting of a high-volume academic hospital: a retrospective analysis of surgical and pathological outcomes

BACKGROUND

Academic hospitals must train future surgeons, but whether residents could negatively affect the outcomes of major procedures is a matter of concern. The aim of this study is to assess if pancreatic surgery is a safe teaching model.

METHODS

Outcomes of 1230 major pancreatic resections performed at a high-volume pancreatic teaching hospital between 2015 and 2018 were compared according to the first surgeon type, attending vs resident.

RESULTS

Residents performed a selection of 132 (16%) pancreaticoduodenectomies (PD) and 46 (11%) distal pancreatectomies (DP). For PD, pancreatic fistula (25% vs 0, p < 0.001), biliary fistula (7.1% vs 3.5%, p = 0.04) and operative time (400 vs 390 min, p < 0.001) were lower for residents but post-pancreatectomy hemorrhage was higher (20.5% vs 13% p = 0.024). For DP, pancreatic fistula rate was lower for residents (31.7% vs 17.5% p = 0.046). There was no difference in terms of lymph nodes retrieval both for PDs and DPs, while the R1 resections were more frequent among PDs performed by attending surgeons (31.5% vs 15.7%, p = 0.023).

CONCLUSION

The active participation of residents does not negatively affect outcomes of major pancreatic resections in a high-volume center. By means of case selection and continuous tutoring, pancreatic surgery represents a safe and valid teaching model.

Extracellular Vesicle Analysis Allows for Identification of Invasive IPMN

BACKGROUND AND AIMS

Advances in cross-sectional imaging have resulted in increased detection of intraductal papillary mucinous neoplasms (IPMNs), and their management remains controversial. At present, there is no reliable noninvasive method to distinguish between indolent and high risk IPMNs. We performed extracellular vesicle (EV) analysis to identify markers of malignancy in an attempt to better stratify these lesions.

METHODS

Using a novel ultrasensitive digital extracellular vesicle screening technique (DEST), we measured putative biomarkers of malignancy (MUC1, MUC2, MUC4, MUC5AC, MUC6, Das-1, STMN1, TSP1, TSP2, EGFR, EpCAM, GPC1, WNT-2, EphA2, S100A4, PSCA, MUC13, ZEB1, PLEC1, HOOK1, PTPN6, and FBN1) in EV from patient-derived cell lines and then on circulating EV obtained from peripheral blood drawn from patients with IPMNs. We enrolled a total of 133 patients in two separate cohorts: a clinical discovery cohort (n = 86) and a validation cohort (n = 47).

RESULTS

From 16 validated EV proteins in plasma samples collected from the discovery cohort, only MUC5AC showed significantly higher levels in high-grade lesions. Of the 11 patients with invasive IPMN (inv/HG), 9 had high MUC5AC expression in plasma EV of the 11 patients with high-grade dysplasia alone, only 1 had high MUC5AC expression (sensitivity of 82%, specificity of 100%). These findings were corroborated in a separate validation cohort. The addition of MUC5AC as a biomarker to imaging and high-riskstigmata allowed detection of all cases requiring surgery, whereas imaging and high-risk stigmata alone would have missed 5 of 14 cases (36%).

CONCLUSIONS

MUC5AC in circulating EV can predict the presence of invasive carcinoma within IPMN. This approach has the potential to improve the management and follow-up of patients with IPMN including avoiding unnecessary surgery.

Abstract PR-007: Single-nucleus and spatial transcriptomics of archival pancreatic ductal adenocarcinoma reveals multi-compartment reprogramming after neoadjuvant treatment

Molecular subtyping of pancreatic ductal adenocarcinoma (PDAC) remains in its nascent stages and does not currently inform clinical management or therapeutic development. Previously identified bulk expression subtypes in the untreated setting were influenced by contaminating stroma whereas single cell RNA-seq (scRNA-seq) of fresh tumors under-represented key cell types. Two consensus subtypes have arisen from these prior efforts: (1) classical-pancreatic, encompassing a spectrum of pancreatic lineage precursors, and (2) basal-like/squamous/quasi-mesenchymal, characterized by loss of endodermal identity and aberrations in chromatin modifiers. Basal-like tumors were associated with poorer responses to chemotherapy and worse survival in the metastatic setting but attempts to refine this binary classification have failed to further stratify patient survival. Recent clinical trials have supported the increasing adoption of neoadjuvant therapy to aggressively address the risk of micro-metastatic spread and to circumvent concerns of treatment tolerance in the postoperative setting. There is an urgent need to understand how preoperative treatment reprograms residual tumor cells to identify additional therapeutic vulnerabilities that can be exploited in combination with neoadjuvant CRT. Here, we developed a robust single-nucleus RNA-seq (snRNA-seq) technique for frozen archival PDAC specimens and used it to study both untreated tumors (n = 15) and those that received neoadjuvant CRT (n = 11). Gene expression programs learned across malignant cell and fibroblast profiles uncovered a clinically relevant molecular taxonomy with improved prognostic stratification (median survival: 11.2 months in highest risk group to 44.7 months in lowest risk group) compared to prior classifications. Moreover, in the neoadjuvant treatment context, there was lower expression of classical-like phenotypes in malignant cells in favor of basal-like phenotypes associated with TNF-NFkB and interferon signaling as well as the presence of novel acinar and neuroendocrine classical-like states, which may be more resilient to cytotoxic treatment. These results suggest that differentiated endodermal phenotypes are only prevalent enough to be detected under treatment selection pressure and when observed in treatment-naïve bulk studies, may reflect normal cell contamination. Spatially-resolved transcriptomics revealed an association between malignant cells expressing basal-like programs and higher immune infiltration with increased lymphocytic content, whereas those exhibiting classical-like programs were linked to sparser macrophage-predominant microniches, perhaps pointing to distinct therapeutic susceptibilities. Our refined molecular taxonomy and spatial resolution may help advance precision oncology in PDAC through informative stratification in clinical trials and insights into differential therapeutic targeting leveraging the immune system.

Citation Format: William L. Hwang, Karthik A. Jagadeesh, Jimmy A. Guo, Hannah I. Hoffman, Eugene Drokhlyansky, Nicholas Van Wittenberghe, Samouil Farhi, Denis Schapiro, Jason Reeves, Daniel R. Zollinger, George Eng, Jason M. Schenkel, William A. Freed-Pastor, Clifton Rodrigues, Domenic Abbondanza, Debora Ciprani, Jennifer Y. Wo, Theodore S. Hong, Andrew J. Aguirre, Orit Rozenblatt-Rosen, Mari Mino-Kenudson, Carlos Fernandez-del Castillo, Andrew S. Liss, Tyler E. Jacks, Aviv Regev. Single-nucleus and spatial transcriptomics of archival pancreatic ductal adenocarcinoma reveals multi-compartment reprogramming after neoadjuvant treatment [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PR-007.

Risk of malignancy in small pancreatic cysts decreases over time

BACKGROUND

Pancreatic cysts <15 mm without worrisome features have practically no risk of malignancy at the time of diagnosis but this can change over time. Optimal duration of follow-up is a matter of debate. We evaluated predictors of malignancy and attempted to identify a time to safely discontinue surveillance.

METHODS

Bi-centric study utilizing prospectively collected databases of patients with pancreatic cysts measuring <15 mm and without worrisome features who underwent surveillance at the Massachusetts General Hospital (1988-2017) and at the University of Verona Hospital Trust (2000-2016). The risk of malignant transformation was assessed using the Kaplan-Meier method and parametric survival models, and predictors of malignancy were evaluated using Cox regression.

RESULTS

806 patients were identified. Median follow-up was 58 months (6-347). Over time, 58 (7.2%) cysts were resected and of those, 11 had high grade dysplasia (HGD) or invasive cancer. Three additional patients had unresectable cancer for a total rate of malignancy of 1.7%. Predictors of development of malignancy included an increase in size ≥2.5 mm/year (HR = 29.54, 95% CI: 9.39-92.91, P < 0.001) and the development of worrisome features (HR = 9.17, 95% CI: 2.99-28.10, P = 0.001). Comparison of parametric survival models suggested that the risk of malignancy decreased after three years of surveillance and was lower than 0.2% after five years.

CONCLUSIONS

Pancreatic cysts <15  mm at the time of diagnosis have a very low risk of malignant transformation. Our findings indicate the risk decreases over time. Size increase of ≥2.5 mm/year is the strongest predictor of malignancy.

Microscopic size measurements in post-neoadjuvant therapy resections of pancreatic ductal adenocarcinoma (PDAC) predict patient outcomes

AIMS

Pancreatic ductal adenocarcinomas (PDACs) are increasingly being treated with neoadjuvant therapy. However, the American Joint Committee on Cancer (AJCC) 8th edition T staging based on tumour size does not reflect treatment effect, which often results in multiple, small foci of residual tumour in a background of mass-forming fibrosis. Thus, we evaluated the performance of AJCC 8th edition T staging in predicting patient outcomes by the use of a microscopic tumour size measurement method.

METHODS AND RESULTS

One hundred and six post-neoadjuvant therapy pancreatectomies were reviewed, and all individual tumour foci were measured. T stages based on gross size with microscopic adjustment (GS) and the largest single microscopic focus size (MFS) were examined in association with clinicopathological variables and patient outcomes. Sixty-three of 106 (59%) were locally advanced; 78% received FOLFIRINOX treatment. The average GS and MFS were 25 mm and 11 mm, respectively; nine cases each were classified as T0, 35 and 85 cases as T1, 42 and 12 cases as T2, and 20 and 0 cases as T3, based on the GS and the MFS, respectively. Higher GS-based and MFS-based T stages were significantly associated with higher tumour regression grade, lymphovascular and perineural invasion, and higher N stage. Furthermore, higher MFS-based T stage was significantly associated with shorter disease-free survival (DFS) (P < 0.001) and shorter overall survival (OS) (P = 0.002). GS was significantly associated with OS (P = 0.046), but not with DFS.

CONCLUSIONS

In post-neoadjuvant therapy PDAC resections, MFS-based T staging is superior to GS-based T staging for predicting patient outcomes, suggesting that microscopic measurements have clinical utility beyond the conventional use of GS measurements alone.

Impact of adjuvant therapy in patients with invasive intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

There is limited data on the efficacy of adjuvant therapy (AT) in patients with invasive intraductal papillary mucinous neoplasms of the pancreas (IPMN). This single center retrospective cohort study aims to assess the impact of AT on survival in these patients.

METHODS

Patients undergoing surgery for invasive IPMN between 1993 and 2018 were included in the study. We compared the clinicopathologic features and evaluated overall survival (OS) using multivariate Cox regression adjusting for adjuvant therapy, age, T and N stage, perineural and lymphovascular invasion. We also assessed survival differences between surgery alone and AT in node negative (N0) and node positive (N+) subgroups.

RESULTS

103 patients were included in the study; 69 underwent surgery alone while 34 also received AT. Patients in the AT group were significantly younger, presented at higher T and N stages and had more perineural and lymphovascular invasion. Median OS in the surgery alone group was 134 months and 65 months in the AT group, p = 0.052. On multivariate analysis, AT was not associated with improved OS; hazard ratio (HR) = 1.03 (0.52-2.05). In N0 patients, compared to surgery alone, AT was associated with a worse median OS (65 vs 167 months, p = 0.03), whereas in N+ patients there was a non-significant improvement (50.5 vs 20.4 months, p = 0.315).

CONCLUSION

AT did not improve survival in the overall cohort even after multivariate analysis. N0 patients have excellent survival, and AT should probably be avoided in them, whereas it may be considered in patients with N+ disease.

An elevated CA 19-9 is associated with invasive cancer and worse survival in IPMN

BACKGROUND

Current guidelines for IPMN include an elevated serum carbohydrate antigen (CA) 19-9 among the worrisome features. However, the correlation of CA 19-9 with histological malignant features and survival is unclear. Serum CEA is also currently used for preoperative management of IPMN, although its measurement is not evidence-based. Accordingly, we aimed to assess the role of these tumor markers as predictors of malignancy in IPMN.

METHODS

IPMN resected between 1998 and 2018 at Massachusetts General Hospital were analyzed. Clinical, pathological and survival data were collected and compared to preoperative levels of CA 19-9 and CEA. Receiver operating characteristic (ROC) and Cox regression analyses were performed considering cut-offs of 37 U/ml (CA 19-9) and 5 μg/l (CEA).

RESULTS

Analysis of 594 patients showed that preoperative CA 19-9 levels > 37 U/ml (n = 128) were associated with an increased likelihood of invasive carcinoma when compared to normal levels (45.3% vs. 18.0%, P < 0.001), while there was no difference with respect to high-grade dysplasia (32.9% vs 31.9%, P = 0.88). The proportion of concurrent pancreatic cancer was higher in patients with CA 19-9 > 37 U/ml (17.2% vs 4.9%, P < 0.001). An elevated CA 19-9 was also associated with worse overall and disease-free survival (HR = 1.943, P = 0.007 and HR = 2.484, P < 0.001 respectively). CEA levels did not correlate with malignancy.

CONCLUSION

In patients with IPMN, serum CA19-9 > 37 U/ml is associated with invasive IPMN and concurrent pancreatic cancer as well as worse survival, but not with high-grade dysplasia. Serum CEA appears to have minimal utility in the management of these patients.

Single-nucleus RNA-seq of frozen archival primary pancreatic ductal adenocarcinoma uncovers multi-compartment intratumoral heterogeneity associated with neoadjuvant treatment

4633

Background: Pancreatic ductal adenocarcinoma (PDAC) remains a treatment-refractory disease and existing molecular subtypes do not inform clinical decisions. Previously identified bulk transcriptomic subtypes of PDAC were often unintentionally driven by “contaminating” stroma. RNA extraction from pancreatic tissue is difficult and prior single-cell RNA-seq efforts have been limited by suboptimal dissociation/RNA quality and poor performance in the setting of neoadjuvant treatment. We developed a robust single-nucleus RNA-seq (sNuc-seq) technique compatible with frozen archival PDAC specimens. Methods: Single nuclei suspensions were extracted from frozen primary PDAC specimens (n = 27) derived from patients with (borderline)-resectable PDAC who underwent surgical resection with or without neoadjuvant chemoradiotherapy (CRT). Approximately 170,000 nuclei were processed with the 10x Genomics Single Cell 3’ v3 pipeline and gene expression libraries were sequenced (Illumina HiSeq X). Results: Distinct nuclei clusters with gene expression profiles/inferred copy number variation analysis consistent with neoplastic, acinar, ductal, fibroblast, endothelial, endocrine, lymphocyte, and myeloid populations were identified with proportions similar to corresponding multiplexed ion beam imaging. Non-negative matrix factorization revealed intra-tumoral heterogeneity shared across patients. Neoplastic cells featured eight distinct transcriptional topics characterized by developmental (epithelial, mesenchymal, endoderm progenitor, neural progenitor) and environmental (anabolic, catabolic, cycling, hypoxic) programs. CAFs exhibited four different transcriptional topics (activated/desmoplastic, myofibroblast, neurogenic, osteochondral). Differential gene expression and gene set enrichment analyses demonstrated that CRT was associated with an enrichment in myogenic programs in CAFs, activation pathways in immune cells, and type I/II interferons in malignant cells. CRT was also associated with a depletion in developmental programs within malignant cells. Conclusions: We uncovered significant intratumoral heterogeneity and treatment-associated differences in the malignant, fibroblast, and immune compartments of PDAC using sNuc-seq. Deconvolution of clinically-annotated bulk RNA-seq cohorts and characterization of intercellular interactions with receptor-ligand analysis and spatial transcriptomics are ongoing.

Diabetes mellitus is associated with unfavorable pathologic features, increased postoperative mortality, and worse long-term survival in resected pancreatic cancer

BACKGROUND

The risk of pancreatic ductal adenocarcinoma (PDAC) is increased in patients with diabetes mellitus (DM), particularly in those with new-onset DM. However, the impact of DM on outcomes following pancreatic surgery is not fully understood. We sought to explore the effects of DM on post-resection outcomes in patients undergoing either upfront resection or following neoadjuvant treatment (NAT).

METHODS

Resections for PDAC between 2007 and 2016 were identified from a prospectively-maintained database. Data on demographics, pathology, and perioperative outcomes were compared between patients with or without DM. Survival analysis was performed using Kaplan-Meier curves and adjusted for confounders by a Cox-proportional hazards model.

RESULTS

662 patients were identified, of whom 277 (41.8%) had DM. Diabetics were more likely to be male, had higher BMI, and higher ASA-scores. At pathology, DM was associated with larger tumors (30 vs. 26 mm; p = 0.041), higher rates of lymph-node involvement (69% vs. 59%; p = 0.031) and perineural invasion (88% vs. 82%; p = 0.026). Despite having similar rates of complications, diabetics experienced higher 30-day mortality (3.2% vs. 0.8%; p = 0.019). Median overall survival was worse in diabetic patients (18 vs. 34 months; p < 0.001); this effect was more pronounced in patients with NAT (18 vs. 54 months; p < 0.001). At multivariate analysis, DM was confirmed as an independent predictor of post-resection survival.

CONCLUSION

DM is a common comorbidity in PDAC and is associated with unfavorable pathology, as well as worse postoperative and oncologic outcomes. The blunted effect on survival is more pronounced in patients who undergo resection following NAT.

Abstract A22: Molecular subtypes and resistance programs in pancreatic ductal adenocarcinoma elucidated with single-nucleus RNA-seq

Objective: Pancreatic ductal adenocarcinoma (PDAC) remains a treatment-refractory disease as existing molecular subtypes are insufficient and do not currently inform clinical decisions. Rare cell types, including those responsible for resistance, are difficult to detect with bulk transcriptomic profiling. Indeed, several previously identified transcriptomic subtypes of PDAC are unintentionally driven by “contaminating” stromal components. Single-cell transcriptomics provides an unprecedented degree of resolution into the properties of individual cells. However, RNA extraction from RNase- and stroma-rich pancreatic tissue is difficult and prior single-cell efforts have been limited by suboptimal dissociation/RNA quality. We developed a robust single-nucleus RNA-seq (sNuc-seq) technique compatible with frozen archival PDAC specimens and computational techniques to identify the transcriptomic programs driving tumor subtypes and therapeutic resistance.

Methods: Patients with localized PDAC undergoing surgical resection with or without neoadjuvant chemoradiotherapy were consented for this IRB-approved study. Specimens were screened for RNA Integrity Number &gt;6. Single nuclei suspensions were extracted from flash-frozen primary PDAC specimens and organoids. Approximately 8,000 nuclei were loaded on the 10x Genomics Chromium platform per sample to generate and sequence 3’ gene expression libraries (Illumina HiSeq 2500, 125 bp paired-end reads). sNuc-seq derived reads were processed using the 10X CellRanger v3.0.2 pipeline. Unsupervised clustering was utilized to identify different cell populations and known marker genes from literature were used to label cell types.

Results: Both treatment-naïve (n=12) and treatment-resistant (n=11) specimens yielded high-quality sNuc-seq data (&gt;1,000 nuclei per sample, &gt;1,000 median genes per nucleus). In each tumor, distinct clusters with gene expression profiles consistent with ductal, fibroblast, endothelial, endocrine, lymphocyte, and myeloid cell populations were identified. Malignant cells were confirmed by inferred copy number variation analysis (InferCNV v3.9) and segregated into several distinct clusters for each individual patient highlighting intratumoral heterogeneity. While some malignant clusters corresponded to previously identified basal-squamous and classical-progenitor bulk subtypes, others featured expression profiles distinct from known subtypes, including cells with upregulation of hypoxia-associated or cytoskeletal genes.

Conclusions: Applying sNuc-seq to treatment-naïve and pretreated PDAC specimens, we uncovered significant intratumoral heterogeneity in the malignant and stromal compartments and identified malignant cells featuring transcriptomic programs that do not fit previously identified bulk subtypes. Characterization of therapeutic resistance programs, spatial relationships among cell types, and association with clinical outcomes is ongoing.

Citation Format: William L. Hwang, Karthik A. Jagadeesh, Orr Ashenberg, Eugene Drokhlyansky, George Eng, Nicholas Van Wittenberghe, William Freed-Pastor, Clifton Rodriguez, Danielle Dionne, Julia Waldman, Michael Cuoco, Alexander Tsankov, Connor Lambden, Caroline Porter, Jason Schenkel, Laurens Lambert, Debora Ciprani, Andrew J. Aguirre, Mari Mino-Kenudson, Theodore S. Hong, Orit Rozenblatt-Rosen, Carlos Fernandez-del Castillo, Andrew S. Liss, Aviv Regev, Tyler E. Jacks. Molecular subtypes and resistance programs in pancreatic ductal adenocarcinoma elucidated with single-nucleus RNA-seq [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr A22.

Outcomes of Primary Chemotherapy for Borderline Resectable and Locally Advanced Pancreatic Ductal Adenocarcinoma

Importance

Chemotherapy is the recommended induction strategy in borderline resectable and locally advanced pancreatic ductal adenocarcinoma. However, the associated results on an intention-to-treat basis are poorly understood.

Objective

To investigate pragmatically the treatment compliance, conversion to surgery, and survival outcomes of patients with borderline resectable and locally advanced pancreatic ductal adenocarcinoma undergoing primary chemotherapy.

Design, Setting, and Participants

This prospective study took place in a national referral center for pancreatic diseases in Italy. Consecutive patients with borderline resectable and locally advanced pancreatic ductal adenocarcinoma were enrolled at the time of diagnosis (January 2013 through December 2015) and followed up to June 2018.

Exposures

The chemotherapy regimen, assigned based on multidisciplinary evaluation, was delivered either at a hub center or at spoke centers. By convention, primary chemotherapy was considered completed after 6 months. After restaging, surgical candidates were selected based on radiologic and biochemical response. All surgeries were carried out at the hub center.

Main Outcomes and Measures

Rates of receipt and completion of chemotherapy, rates of conversion to surgery, and disease-specific survival.

Results

Of 680 patients, 267 (39.3%) had borderline resectable and 413 (60.7%) had locally advanced pancreatic ductal adenocarcinoma. Overall, 66 patients (9.7%) were lost to follow-up. The rate of chemotherapy receipt was 92.9% (n = 570). The chemotherapeutic regimens most commonly used included FOLFIRINOX (fluorouracil, leucovorin, oxaliplatin, and irinotecan) (260 [45.6%]) and gemcitabine plus nanoparticle albumin-bound-paclitaxel (123 [21.6%]). Nineteen patients (3.3%) receiving chemotherapy died within 6 months, mainly for disease progression. The treatment completion rate was 71.6% (408 of 570). The overall rate of resection was 15.1% (93 of 614) (borderline resectable, 60 of 249 [24.1%]; locally advanced, 33 of 365 [9%]; resection:exploration ratio, 63.3%). Independent predictors of resection were age, borderline resectable disease, chemotherapy completion, radiologic response, and biochemical response. The median survival for the whole cohort was 12.8 (95% CI, 11.7-13.9) months. Factors independently associated with survival were completion of chemotherapy, receipt of complementary radiation therapy, and resection. In patients who underwent resection, the median survival was 35.4 (95% CI, 27.0-43.7) months for initially borderline resectable and 41.8 (95% CI, 27.5-56.1) months for initially locally advanced disease. No pretreatment and posttreatment factors were associated with survival after pancreatectomy.

Conclusions and Relevance

This pragmatic observational cohort study with an intention-to-treat design provides real-world evidence of outcomes associated with the most current primary chemotherapy regimens used for borderline resectable and locally advanced pancreatic ductal adenocarcinoma.

Impact of preoperative biliary drainage on postoperative outcome after pancreaticoduodenectomy: An analysis of 1500 consecutive cases

BACKGROUND AND AIM

Implications of preoperative biliary drain on morbidity and mortality after pancreatoduodenectomy are still controversial. The present study aims to assess the impact of preoperative biliary drain on postoperative outcome and to define optimal serum bilirubin cut-off to recommend biliary drainage in patients undergoing pancreatoduodenectomy.

METHODS

All consecutive pancreatoduodenectomies carried out at Verona Hospital from 2005 to 2016 were retrospectively analyzed. The study population was divided into three groups: preoperative biliary drained (Stented Group), preoperative jaundice without drainage (Jaundiced Group) and the control group of non-jaundiced, non-stented patients (Control Group).

RESULTS

A total of 1500 patients were included. Seven hundred and fourteen patients (47.6%) received biliary drain (stented group), 258 (17.2%) patients did not (jaundiced group) and 528 (35.2%) patients represented the (control group). Major complications and mortality rates did not differ between groups. Conversely, the risk of developing surgical site infections doubled in the stented group (18.1%) (OR = 2.1, 95% CI = 1.5-2.8). In jaundiced patients, a preoperative bilirubin value greater than 7.5 mg/dL (128 μmol/L) accurately predicted the likelihood of postoperative complications.

CONCLUSION

Preoperative biliary drain does not increase major complications and mortality rates after pancreatoduodenectomy, but it is associated with higher surgical site infection rates. In jaundiced patients, a bilirubin value greater than 7.5 mg/dL (128 μmol/L) should indicate biliary drainage.

Pancreaticoduodenectomy in patients ≥ 75 years of age: Are there any differences with other age ranges in oncological and surgical outcomes? Results from a tertiary referral center

AIM

To compare surgical and oncological outcomes after pancreaticoduodenectomy (PD) in patients ≥ 75 years of age with two younger cohorts of patients.

METHODS

The prospectively maintained Institutional database of pancreatic resection was queried for patients aged ≥ 75 years (late elderly, LE) submitted to PD for any disease from January 2010 to June 2015. We compared clinical, demographic and pathological features and survival outcomes of LE patients with 2 exact matched cohorts of younger patients [≥ 40 to 64 years of age (adults, A) and ≥ 65 to 74 years of age (young elderly, YE)] submitted to PD, according to selected variables.

RESULTS

The final LE population, as well as the control groups, were made of 96 subjects. Up to 71% of patients was operated on for a periampullary malignancy and pancreatic cancer (PDAC) accounted for 79% of them. Intraoperative data (estimated blood loss and duration of surgery) did not differ among the groups. The overall complication rate was 65.6%, 61.5% and 58.3% for LE, YE and A patients, respectively, P = NS). Reoperation and cardiovascular complications were significantly more frequent in LE than in YE and A groups (P = 0.003 and P = 0.019, respectively). When considering either all malignancies and PDAC only, the three groups did not differ in survival. Considering all benign diseases, the estimated mean survival was 58 and 78 mo for ≥ and < 75 years of age (YE + A groups), respectively (P = 0.012).

CONCLUSION

Age is not a contraindication for PD. A careful selection of LE patients allows to obtain good surgical and oncological results.