Chemotherapy-free treatment targeting fusions and driver mutations in KRAS wild-type pancreatic ductal adenocarcinoma, a case series.

Background: KRAS wild-type (WT) pancreatic ductal adenocarcinoma (PDAC) represents a distinct entity with unique biology. The therapeutic impact of matched targeted therapy in these patients in a real-world setting, to date, is less established. Objectives: The aim of our study was to review our institutional database to identify the prevalence of actionable genomic alterations in patients with KRAS-WT tumors and to evaluate the therapeutic impact of matched targeted therapy in these patients. Design: We reviewed electronic medical records of patients with KRAS-WT PDAC and advanced disease (n = 14) who underwent clinical-grade tissue ± liquid next-generation sequencing (315-648 genes for tissue) between years 2015 and 2021. Methods: Demographic and disease characteristics were summarized using descriptive parameters. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Results: Of 236 PDAC patients, 14 had advanced/metastatic disease with KRAS-WT tumors. Median age at diagnosis was 66 years. There was a high frequency of potentially actionable genomic alterations, including three (21%) with BRAF alterations, two (14%) with fusions [RET-PCM1 and FGFR2-POC1B (N = 1 each)]; and one with a druggable EGFR (EGFR E746_A755delISERD) variant; two other patients had an STK11 and a MUTYH alteration. Five patients were treated with matched targeted therapy, with three having durable benefit: (i) erlotinib for EGFR-altered tumor, followed by osimertinib/capmatinib when MET amplification emerged (first-line therapy); (ii) pralsetinib for RET fusion (fifth line); and (iii) dabrafenib/trametinib for BRAF N486_P490del (third line). Duration of time on chemotherapy-free matched targeted therapy for these patients was 17+, 11, and 18+ months, respectively. Conclusion: Sustained therapeutic benefit can be achieved in a real-world setting in a subset of patients with advanced/metastatic KRAS-WT PDAC treated with chemotherapy-free matched targeted agents. Prospective studies are warranted.

Median arcuate ligament release at the time of pancreaticoduodenectomy or total pancreatectomy.

BACKGROUND: Celiac artery compression can complicate the performance of pancreaticoduodenectomy or total pancreatectomy due to the need for ligation of the gastroduodenal artery. Median arcuate ligament release restores normal arterial flow to the liver, spleen, and stomach and may avoid complications related to poor perfusion of the foregut. METHODS: All patients who underwent median arcuate ligament release for celiac artery compression at the time of pancreatectomy between 2009 and 2023 were reviewed. Pre- and postoperative computed tomography was used to categorize celiac artery compression by the extent of compression (types A [<50%], B [50%-80%], and C [>80%]). RESULTS: Of 695 patients who underwent pancreatectomy, 22 (3%) had celiac artery compression, and a majority (17) were identified on preoperative imaging. Median celiac artery compression was 52% (interquartile range = 18); 8 (36%) patients had type A and 14 (64%) had type B compression with a median celiac artery compression of 39% (interquartile range = 18) and 59% (interquartile range = 14), respectively (P < .001). Postoperative imaging was available for 20 (90%) patients, and a reduction in the median celiac artery compression occurred in all patients: type A, 14%, and type B, 31%. Complications included 1 (5%) death after hospital discharge, 1 (5%) pancreatic fistula, 1 (5%) delayed gastric emptying, and 4 (18%) readmissions. No patient had evidence of a biliary leak or liver dysfunction. CONCLUSION: Preoperative computed tomography allows accurate identification of celiac artery compression. Ligation of the gastroduodenal artery during pancreaticoduodenectomy or total pancreatectomy in the setting of celiac artery compression requires median arcuate ligament release to restore normal arterial flow to the foregut and avoid preventable complications.

Transcriptomic-Based Microenvironment Classification Reveals Precision Medicine Strategies for Pancreatic Ductal Adenocarcinoma.

BACKGROUND & AIMS: The complex tumor microenvironment (TME) of pancreatic ductal adenocarcinoma (PDAC) has hindered the development of reliable predictive biomarkers for targeted therapy and immunomodulatory strategies. A comprehensive characterization of the TME is necessary to advance precision therapeutics in PDAC. METHODS: A transcriptomic profiling platform for TME classification based on functional gene signatures was applied to 14 publicly available PDAC datasets (n = 1657) and validated in a clinically annotated independent cohort of patients with PDAC (n = 79). Four distinct subtypes were identified using unsupervised clustering and assessed to evaluate predictive and prognostic utility. RESULTS: TME classification using transcriptomic profiling identified 4 biologically distinct subtypes based on their TME immune composition: immune enriched (IE); immune enriched, fibrotic (IE/F); fibrotic (F); and immune depleted (D). The IE and IE/F subtypes demonstrated a more favorable prognosis and potential for response to immunotherapy compared with the F and D subtypes. Most lung metastases and liver metastases were subtypes IE and D, respectively, indicating the role of clonal phenotype and immune milieu in developing personalized therapeutic strategies. In addition, distinct TMEs with potential therapeutic implications were identified in treatment-naive primary tumors compared with tumors that underwent neoadjuvant therapy. CONCLUSIONS: This novel approach defines a distinct subgroup of PADC patients that may benefit from immunotherapeutic strategies based on their TME subtype and provides a framework to select patients for prospective clinical trials investigating precision immunotherapy in PDAC. Further, the predictive utility and real-world clinical applicability espoused by this transcriptomic-based TME classification approach will accelerate the advancement of precision medicine in PDAC.

Characterization of an oligometastatic state in patients with metastatic pancreatic adenocarcinoma undergoing systemic chemotherapy.

PURPOSE/OBJECTIVES: Most patients with pancreatic adenocarcinoma (PDAC) will present with distant metastatic disease at diagnosis. We sought to identify clinical characteristics associated with prolonged overall survival (OS) in patients presenting with metastatic PDAC. MATERIALS/METHODS: Patients presenting with metastatic PDAC that received treatment at our institution with FOLFIRINOX or gemcitabine-based chemotherapies between August 1, 2011 and September 1, 2017 were included in the study. Metastatic disease burden was comprehensively characterized radiologically via individual diagnostic imaging segmentation. Landmark analysis was performed at 18 months, and survival curves were estimated using the Kaplan-Meier method and compared between groups via the log-rank test. ECOG and Charlson Comorbidity Index (CCI) were calculated for all patients. RESULTS: 121 patients were included with a median age of 62 years (37-86), 40% were female, 25% had ECOG 0 at presentation. Of the 121 patients included, 33% (n = 41) were alive at 12 months and 25% (n = 31) were alive at 18 months. Landmark analysis demonstrated a significant difference between patients surviving <18 months and ≥18 months regarding the presence of lung only metastases (36% vs. 16%, p = 0.04), number of organs with metastases (≥2 vs. 1, p = 0.04), and disease volume (mean of 19.1 cc vs. 1.4 cc, p = 0.04). At Year 1, predictors for improved OS included ECOG status at diagnosis (ECOG 0 vs. ECOG 1, p = 0.04), metastatic disease volume at diagnosis (≤0.1 cc vs. >60 cc, p = 0.004), metastasis only in the liver (p = 0.04), and normalization of CA 19-9 (p < 0.001). At Year 2, the only predictor of improved OS was normalization of the CA 19-9 (p = 0.03). In those patients that normalized their CA 19-9, median overall survival was 16 months. CONCLUSIONS: In this exploratory analysis normalization of CA-19-9 or volumetric metastatic disease burden less than 0.2 cc demonstrated a remarkable OS, similar to that of patients with non-metastatic disease. These metrics are useful for counseling patients and identifying cohorts that may be optimal for trials exploring metastatic and/or local tumor-directed interventions.

Automated machine learning (AutoML) can predict 90-day mortality after gastrectomy for cancer.

Early postoperative mortality risk prediction is crucial for clinical management of gastric cancer. This study aims to predict 90-day mortality in gastric cancer patients undergoing gastrectomy using automated machine learning (AutoML), optimize models for preoperative prediction, and identify factors influential in prediction. National Cancer Database was used to identify stage I-III gastric cancer patients undergoing gastrectomy between 2004 and 2016. 26 features were used to train predictive models using H2O.ai AutoML. Performance on validation cohort was measured. In 39,108 patients, 90-day mortality rate was 8.8%. The highest performing model was an ensemble (AUC = 0.77); older age, nodal ratio, and length of inpatient stay (LOS) following surgery were most influential for prediction. Removing the latter two parameters decreased model performance (AUC 0.71). For optimizing models for preoperative use, models were developed to first predict node ratio or LOS, and these predicted values were inputted for 90-day mortality prediction (AUC of 0.73-0.74). AutoML performed well in predicting 90-day mortality in a larger cohort of gastric cancer patients that underwent gastrectomy. These models can be implemented preoperatively to inform prognostication and patient selection for surgery. Our study supports broader evaluation and application of AutoML to guide surgical oncologic care.

Patterns of Unnecessary Insurer Prior Authorization Denials in a Complex Surgical Oncology Practice.

INTRODUCTION: Insurance prior authorization (PA) is a determination of need, required by a health insurer for an ordered test/procedure. If the test/procedure is denied, a peer-to-peer (P2P) discussion between ordering provider and payer is used to appeal the decision. The objective of this study was to measure the number and patterns of unnecessary PA denials. METHODS: This was a retrospective review at a quaternary cancer center from October 2021 to March 2022. Included were all patients with outpatient imaging orders for surgical planning or surveillance of gastrointestinal, endocrine, or skin cancer. Primary outcome was unnecessary initial denial (UID) defined as an order that required preauthorization, was initially denied by the insurer, and subsequently overturned by P2P. RESULTS: Nine hundred fifty seven orders were placed and 419 required PA (44%). Of tests requiring authorization, 55/419 (13.1%) were denied. Variability in the likelihood of initial denial was seen across insurers, ranging from 0% to 57%. Following P2P, 32/55 were overturned (58.2% UID). The insurers most likely to have a UID were Aetna (100%), Anthem (77.8%), and Cigna (50.0%). UID was most common for gastrointestinal (58.9%) and endocrine (58.3%) cancers. Average P2P was 33.5 min (interquartile range 28-40). CONCLUSIONS: The majority of imaging studies initially denied were overturned after P2P. If all UIDs were eliminated, this would represent 108 less P2P discussions with an estimated time-savings of 60.3 h annually within a high-volume surgical oncology practice. Combined personnel costs to the health systems and stress on patients with cancer due to image-associated PAs and P2P appear hard to justify.

Biliary Adverse Events During Neoadjuvant Therapy for Pancreatic Cancer.

OBJECTIVE: To describe a high-volume experience with biliary drainage before neoadjuvant therapy (NAT) for patients with operable pancreatic cancer (PC) and characterize the association between biliary adverse events (BAEs) and patient outcome. BACKGROUND: Patients with PC presenting with biliary obstruction require durable decompression before NAT. METHODS: Patients with operable PC and tumor-associated biliary obstruction were examined and grouped by the presence or absence of a BAE during NAT. The incidence, timing, and management of BAEs are described, and outcomes, including the completion of all treatment and overall survival (OS), were compared. RESULTS: Of 426 patients who received pretreatment biliary decompression, 92 (22%) experienced at least 1 BAE during NAT, and 56 (13%) required repeat intervention on their biliary stent. The median duration of NAT was 161 days for all patients and was not different in the group that experienced BAEs. The median time from initial stent placement to BAE was 64 days. An interruption in the delivery of NAT (median 7 days) occurred in 25 (6%) of 426 patients. Among 426 patients, 290 (68%) completed all NAT, including surgery: 60 (65%) of 92 patients with BAE and 230 (69%) of 334 patients without BAE ( P =0.51). Among 290 patients who completed NAT and surgery, the median OS was 39 months, 26 months for the 60 patients with BAE, and 43 months for the 230 patients without BAE ( P =0.02). CONCLUSIONS: During extended multimodal NAT for PC, 22% of patients experienced a BAE. Although BAEs were not associated with a significant interruption of treatment, patients who experienced a BAE had worse OS.

Neoadjuvant chemotherapy for pancreatic cancer: Quality over quantity.

BACKGROUND AND OBJECTIVES: The ideal duration of neoadjuvant chemotherapy (NACT) in patients with localized pancreatic adenocarcinoma (PDAC) treated with curative intent is unclear. We sought to determine the prognostic significance of both duration of NACT and Carbohydrate Antigen 19-9 (CA19-9) normalization to NACT. METHODS: We examined patients with resectable and borderline resectable PDAC treated with NACT and chemoradiation. Patients were compared by NACT duration (2 vs. 4 months) and by CA19-9 normalization after NACT. RESULTS: Among 171 patients, 83 (49%) received 2 months of NACT, and 88 (51%) received 4 months. After NACT completion, 115 (67%) patients had persistently elevated CA19-9, and 56 (33%) had normalized. Of the 125 patients who had successful surgery, 73 (58%) had normalized CA19-9 postoperatively. Duration of NACT was not associated with overall survival (OS) while CA19-9 normalization after NACT (regardless of duration) was associated with improved OS (hazard ratio [HR] 0.56, 95% confidence interval [CI] 0.35-0.89, p = 0.02). Adjuvant chemotherapy was associated with improved OS among patients without CA19-9 normalization after NACT (HR 0.42, CI 0.20-0.86, p = 0.02) but not among those that normalized, independent of duration. CONCLUSIONS: CA19-9 normalization after NACT is a clinically significant endpoint of treatment; patients without CA19-9 normalization may benefit from additional therapy.

CA19-9 Response to First-Line Neoadjuvant FOLFIRINOX and Second-Line Gemcitabine/Nab-Paclitaxel for Patients with Operable Pancreatic Cancer.

BACKGROUND: Response to second-line (2L) neoadjuvant therapy for operable pancreatic cancer (PC) is understudied. This study examined carbohydrate antigen 19-9 (CA19-9) response to first-line (1L) and 2L chemotherapy. METHODS: The study identified patients with operable PC and elevated CA19-9 (≥ 35 U/mL with total bilirubin < 2 mg/dL) who received 1L FOLFIRINOX (FFX). The patients were restaged after 2 months and based on response, received additional FFX or gemcitabine/nab-paclitaxel (GnP) as part of total neoadjuvant therapy. Response was defined as a decrease in tumor size on computed tomography (CT) imaging or a decline in CA19-9 of 50% or more and preserved performance status. RESULTS: For operable PC with an elevated CA19-9, 108 patients received 1L FFX. After 2 months of chemotherapy, the decision was made to continue FFX (FFX ≥ FFX) for 76 (70%) of the 108 patients and switch to GnP (FFX ≥ GnP)) for 32 (30%) of the patients. Of the 32 FFX ≥ GnP patients, 27 had no evidence of radiographic or biochemical (CA19-9) response to 1L FFX. Of these 27 patients, 26 (96%) demonstrated a response to 2L GnP. After 4 months of chemotherapy, 62 (82%) of the 76 FFX ≥ FFX patients had a CA19-9 response compared with 31 (97%) of the 32 FFX ≥ GnP patients (p = 0.04). CONCLUSIONS: Lack of biochemical response to 2 months of 1L FFX may identify a subgroup of patients with a very high rate of response to 2L GnP, emphasizing the importance of assessing treatment response at 2-month intervals.

Updates and new directions in the use of radiation therapy for the treatment of pancreatic adenocarcinoma: dose, sensitization, and novel technology.

Panc reatic ductal adenocarcinoma (PDAC) is a devastating malignancy. There have been few advances that have substantially improved overall survival in the past several years. On its current trajectory, the deaths from PDAC are expected to cross that from all gastrointestinal cancers combined by 2030. Radiation therapy is a technically very complex modality that bridges multiple different treatment strategies. It represents a hybrid among advanced diagnostic imaging, local (often ablative) intervention, and heterogeneous biological mechanisms contributing to normal and oncologic cell kill. In this article, we bring an overview of the several promising strategies that are currently being investigated to improve outcomes using radiation therapy for patients with PDAC.

Pancreaticoduodenectomy and Vascular Reconstruction: Indications and Techniques.

Pancreaticoduodenectomy with vascular resection/reconstruction can be safely completed following 6 standard steps plus basic principles of vascular surgery. Particular attention is paid to the location of the tumor relative to the 2 first-order vein branches, portal vein -splenic vein -superior mesenteric vein confluence, inferior mesenteric vein, and the presence of arterial perineural invasion. Successful resection following neoadjuvant therapy can result in median survival 3 times that of historical controls.

Two-Stage Hepatectomy for Bilateral Colorectal Liver Metastases: A Multi-institutional Analysis.

BACKGROUND: Two-stage hepatectomy (TSH) is an important tool in the management of bilateral colorectal liver metastases (CRLM). This study sought to examine the presentation, management, and outcomes of patients completing TSH in major hepatobiliary centers in the United States (US). METHODS: A retrospective review from five liver centers in the US identified patients who completed a TSH procedure for bilateral CRLM. RESULTS: From December 2000 to March 2016, a total of 196 patients were identified. The majority of procedures were performed using an open technique (n = 194, 99.5%). The median number of tumors was 7 (range 2-33). One-hundred and twenty-eight (65.3%) patients underwent portal vein embolization. More patients received chemotherapy prior to the first stage than chemotherapy administration preceding the second stage (92% vs. 60%, p = 0.308). Median overall survival (OS) was 50 months, with a median follow-up of 28 months (range 2-143). Hepatic artery infusion chemotherapy was administered to 64 (32.7%) patients with similar OS as those managed without an infusion pump (p = 0.848). Postoperative morbidity following the second-stage resection was 47.4%. Chemotherapy prior to the second stage did not demonstrate an increased complication rate (p = 0.202). Readmission following the second stage was 10.3% and was associated with a decrease in disease-free survival (p = 0.003). OS was significantly decreased by positive resection margins and increased estimated blood loss (EBL; p = 0.036 and p = 0.05, respectively). CONCLUSION: This is the largest TSH series in the US and demonstrates evidence of safety and feasibility in the management of bilateral CRLM. Outcomes are influenced by margin status and operative EBL.

Adjuvant therapy rates and overall survival in patients with localized pancreatic cancer from high Area Deprivation Index neighborhoods.

BACKGROUND: Neighborhood adversity's impact on postoperative/adjuvant therapy delivery and overall survival (OS) is poorly described in patients with localized pancreatic cancer (PC). METHODS: Area Deprivation Index (ADI) is a validated measure classifying neighborhood adversity. Higher ADI signifies increasing adversity. The 2013 national ADI scores were obtained from patients who completed preoperative/neoadjuvant therapy and surgery. Patients were categorized as having high (>50%) or low (≤50%) ADI. RESULTS: Of the 224 patients, 163 (73%) had low ADI and 61 (27%) had high ADI. Adjuvant therapy was delivered to 129 (58%) patients, including 62% (101/163) with low ADI and 46% (28/61) with high ADI (p = 0.03). Patients with high ADI had 55% (95%CI 0.23-0.86; p = 0.02) decreased odds of receiving adjuvant therapy, independent of other factors. The median OS was 45 months for 129 patients who received adjuvant therapy and 31 months for 94 patients who did not receive adjuvant therapy (p = 0.03). CONCLUSIONS: Patients with high ADI are less likely to receive adjuvant therapy for localized PC. Future studies should address impediments to care in patients from higher ADI neighborhoods.

Total Neoadjuvant Therapy for Operable Pancreatic Cancer.

BACKGROUND: Overall survival (OS) for operable pancreatic cancer (PC) is optimized when 4-6 months of nonsurgical therapy is combined with pancreatectomy. Because surgery renders the delivery of postoperative therapy uncertain, total neoadjuvant therapy (TNT) is gaining popularity. METHODS: We performed a retrospective cohort study of patients with operable PC and compared TNT with shorter course neoadjuvant therapy (SNT). Primary outcomes of interest included completion of neoadjuvant therapy (NT) and resection of the primary tumor, receipt of 5 months of nonsurgical therapy, and median OS. RESULTS: We reviewed 541 consecutive patients from 2009 to 2019 including 226 (42%) with resectable PC and 315 (58%) with borderline resectable (BLR) PC. The median age was 66 years (IQR [59, 72]), and 260 (48%) patients were female. TNT was administered to 89 (16%) patients and SNT was administered to 452 (84%). Both groups were equally likely to complete intended NT and surgery (p = 0.90). Patients who received TNT and surgical resection were more likely to have a complete pathologic response (8% vs 4%, p < 0.01) and were more likely to receive at least 5 months of nonsurgical therapy (67% vs 45%, p < 0.01). The median OS was 26 months [IQR (15, 57)]; not reached among patients treated with TNT, and 25 months [IQR (15, 56)] among patients treated with SNT (p = 0.19). CONCLUSIONS: TNT ensures the delivery of intended systemic therapy prior to a complicated operation without decreasing the chance of successful surgery; a window of operability was not lost. Patients who can tolerate SNT will likely benefit from TNT.

Radiographic patterns of first disease recurrence after neoadjuvant therapy and surgery for patients with resectable and borderline resectable pancreatic cancer.

BACKGROUND: More than 70% of patients with localized pancreatic cancer treated with upfront surgery develop disease recurrence. Herein we describe the radiographic patterns and timing of disease recurrence after neoadjuvant therapy and surgery in patients with pancreatic cancer. METHODS: Radiographic patterns of first disease recurrence were examined in patients with localized pancreatic cancer who completed neoadjuvant therapy and surgery. Disease recurrence was classified as local (pancreas, resection bed, or peripancreatic vasculature); regional (peritoneum or abdominal wall); or distant (liver, lung, bone). Progression-free survival was calculated from the date of diagnosis to the date of recurrence. RESULTS: Of 306 consecutive patients who completed neoadjuvant therapy and surgery, 149 (49%) had resectable pancreatic cancer and 157 (51%) had borderline resectable disease. Neoadjuvant therapy consisted of chemoradiation (32%), chemotherapy (14%), or both therapies (54%). Overall, primary therapy (including preoperative and postoperative therapy) consisted of chemoradiation alone in 29 (9%), chemotherapy alone in 14 (5%), and both therapies in 263 (86%) patients. At a median follow-up of 27 months, 186 (61%) of the 306 patients had recurrent pancreatic cancer. Sites of first recurrence were local-only in 29 (9%), regional-only in 19 (6%), distant-only in 87 (28%), and multisite in 51 (17%). The overall median progression-free survival for all patients was 24 months. Neoadjuvant chemoradiation reduced the odds of local-only recurrence (odds ratio: 0.21; 95% confidence interval: 0.06-0.77; P = .02). CONCLUSION: After neoadjuvant therapy and surgery, 9% of patients were found to have local-only recurrence. Treatment sequencing that incorporates neoadjuvant chemoradiation may improve local disease control.

Value of Pretreatment 18F-fluorodeoxyglucose Positron Emission Tomography in Patients With Localized Pancreatic Cancer Treated With Neoadjuvant Therapy.

Background: 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) imaging is not routine in patients with localized pancreatic cancer (PC). We evaluated the prognostic value of PET/CT in patients who received neoadjuvant therapy. Methods: Patients with localized PC underwent pretreatment PET/CT with or without posttreatment (preop) PET/CT. Maximum standardized uptake values (SUV) were classified as high or low based on a cut point of 7.5 at diagnosis (SUVdx) and 3.5 after neoadjuvant therapy (preoperative; SUVpreop). Preop carbohydrate antigen 19-9 (CA19-9) was classified as normal ( ≤ 35 U/mL) or elevated. Results: Pretreatment PET/CT imaging was performed on 201 consecutive patients; SUVdx was high in 98 (49%) and low in 103 (51%). Preop PET/CT was available in 104 (52%) of the 201 patients; SUVpreop was high in 60 (58%) and low in 44 (42%). Following neoadjuvant therapy, preop CA19-9 was normal in 90 (45%) patients and elevated in 111 (55%). Median overall survival (OS) of all patients was 27 months; 33 months for the 103 patients with a low SUVdx and 22 months for the 98 patients with a high SUVdx (p = 0.03). Median OS for patients with low SUVdx/normal preop CA19-9, high SUVdx/normal preop CA19-9, low SUVdx/elevated preop CA19-9, and high SUVdx/elevated preop CA19-9 were 66, 34, 23, and 17 months, respectively (p < 0.0001). OS was 44 months for the 148 (74%) patients who completed all intended neoadjuvant therapy and surgery and 13 months for the 53 (26%) who did not undergo surgery (p < 0.001). Conclusion: Pretreatment PET/CT avidity and preop CA19-9 are clinically significant prognostic markers in patients with PC.

Impact of Neoadjuvant Chemoradiation on Pathologic Response in Patients With Localized Pancreatic Cancer.

Introduction/Background: Multimodal neoadjuvant therapy has resulted in increased rates of histologic response in pancreatic tumors and adjacent lymph nodes. The biologic significance of the collective response in the primary tumor and lymph nodes is not understood. Methods: Patients with localized PC who received neoadjuvant therapy and surgery with histologic assessment of the primary tumor and local-regional lymph nodes were included. Histopathologic response was classified using the modified Ryan score as follows: no viable cancer cells (CR), rare groups of cancer cells (nCR), residual cancer with evident tumor regression (PR), and extensive residual cancer with no evident tumor regression (NR). Nodal status was defined by number of lymph nodes (LN) with tumor metastases: N0 (0 LN), N1 (1-3), N2 (≥4). Results: Of 341 patients with localized PC who received neoadjuvant therapy and surgery, 107 (31%) received chemoradiation alone, 44 (13%) received chemotherapy alone, and 190 (56%) received chemotherapy and chemoradiation. Histopathologic response consisted of 15 (4%) CRs, 59 (17%) nCRs, 188 (55%) PRs, and 79 (23%) NRs. Patients who received chemotherapy alone had the worst responses (n = 21 for NR, 48%) as compared to patients who received chemoradiation alone (n = 25 for NR, 24%) or patients who received both therapies (n = 33 for NR, 17%) (Table 1; p = 0.001). Median overall survival for all 341 patients was 39 months; OS by histopathologic subtype was not reached (CR), 49 months (nCR), 38 months (PR), and 34 months (NR), respectively (p = 0.004). Of the 341 patients, 208 (61%) had N0 disease, 97 (28%) had N1 disease, and 36 (11%) had N2 disease. In an adjusted hazards model, modified Ryan score of PR or NR (HR: 1.71; 95% CI: 1.15-2.54; p = 0.008) and N1 (HR: 1.42; 95% CI: 1.1.02-2.01; p = 0.04), or N2 disease (HR: 2.54, 95% CI: 1.64-3.93; p < 0.001) were associated with increased risk of death. Conclusions: Neoadjuvant chemotherapy alone is associated with lower rates of pathologic response. Patients with CR or nCR have a significantly improved OS as compared to patients with PR or NR. Nodal status is the most important pathologic prognostic factor. Neoadjuvant chemoradiation may be an important driver of pathologic response.