IDH1 inhibition potentiates chemotherapy efficacy in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is associated with a five-year overall survival rate of just 13%, and development of chemotherapy resistance is nearly universal. PDAC cells overexpress wild-type IDH1 that can enable them to overcome metabolic stress, suggesting it could represent a therapeutic target in PDAC. Here, we found that anti-IDH1 therapy enhanced the efficacy of conventional chemotherapeutics. Chemotherapy treatment induced ROS and increased TCA cycle activity in PDAC cells, along with the induction of wild-type IDH1 expression as a key resistance factor. IDH1 facilitated PDAC survival following chemotherapy treatment by supporting mitochondrial function and antioxidant defense to neutralize reactive oxygen species through the generation of alpha-ketoglutarate and NADPH, respectively. Pharmacologic inhibition of wild-type IDH1 with ivosidenib synergized with conventional chemotherapeutics in vitro and potentiated the efficacy of sub-therapeutic doses of these drugs in vivo in murine PDAC models. This promising treatment approach is translatable through available and safe oral inhibitors and provides the basis of an open and accruing clinical trial testing this combination (NCT05209074).

Outcomes of Hepatic Artery-Based Therapies and Systemic Multiagent Chemotherapy in Unresectable Colorectal Liver Metastases: A Systematic Review and Meta-analysis.

BACKGROUND: Treatment of unresectable colorectal liver metastases (UCRLM) includes locoregional and systemic therapy. A comprehensive analysis capturing long-term outcomes of these treatment options has not been performed. OBJECTIVE: A systematic review and meta-analysis was performed to calculate pooled outcomes of hepatic artery infusion with systemic chemotherapy (HAI-S), transarterial chemoembolization with systemic chemotherapy (TACE-S), transarterial radioembolization with systemic chemotherapy (TARE-S), doublet (FOLFOX, FOLFIRI), and triplet chemotherapy (FOLFOXIRI). METHODS: Outcomes included overall survival (OS), progression-free survival (PFS), rate of conversion to resection (CTR), and response rate (RR). RESULTS: A total of 32, 7, 9, and 14 publications were included in the HAI-S, TACE-S, and TARE-S chemotherapy arms. The 6/12/24/36-month OS estimates for HAI-S, TACE-S, TARE-S, FOLFOX, FOLFIRI, and FOLFOXIRI were 97%/80%/54%/35%, 100%/83%/40%/14%, 82%/61%/34%/21%, 96%/83%/53%/36%, and 96%/93%/72%/55%. Similarly, the 6/12/24/36-month PFS estimates were 74%/44%/19%/14%, 66%/20%/9%/3%, 57%/23%/10%/3%, 69%/30%/12%/7%, and 88%/55%/18%/11%. The corresponding CTR and RR rates were 31, 20%, unmeasurable (TARE-S), 35, 53; and 49, 45, 45, 50, 80%, respectively. The majority of chemotherapy studies included first-line therapy and liver-only metastases, whereas most HAI-S studies were pretreated. On subgroup analysis in first-line setting with liver-only metastases, the HAI-S arm had comparable outcomes to FOLFOXIRI and outperformed doublet chemotherapy regimens. Although triplet chemotherapy appeared to outperform other arms, high toxicity and inclusion of potentially resectable patients must be considered while interpreting results. CONCLUSIONS: HAI-S and multiagent chemotherapy are effective therapies for UCRLM. To make definitive conclusions, a randomized trial with comparable patient characteristics and line of therapy will be required. The upcoming EA2222 PUMP trial may help to address this question.

Risk factors of developing nonalcoholic fatty liver disease after pancreatic resection: a systematic review and meta-analysis.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) occurs in 10% to 40% of patients after pancreatic resection. Pancreatic exocrine insufficiency (PEI) is thought to be closely associated with NAFLD; however, the mechanism of NAFLD is not clearly understood. We perform a systematic review and meta-analysis to better understand the risk factors of NAFLD. METHODS: A systematic literature search was performed in the MEDLINE database. Studies focused on the risk factors associated with NAFLD in patients undergoing pancreatectomy. The odds ratios (ORs) denoting the association of risk factors with NAFLD after resection were curated. RESULTS: Of 814 published articles, 26 studies met the inclusion criteria. Combined, these studies included clinical data on 4055 patients. The pooled incidence of NAFLD was 29% (23%-35%). Among the various risk factors analyzed, the following had a significant likelihood of NAFLD on forest plot analysis: female gender (OR, 2.44), pancreatic ductal adenocarcinoma (OR, 2.11), portal vein or superior mesenteric vein resection (OR, 1.99), dissection of nerve plexus around the superior mesenteric artery (OR, 1.93), and adjuvant chemotherapy (OR, 1.58). Only 2 studies investigated 2 different measurements of quantitative PEI, which could not be used for analysis. Owing to heterogeneity of studies, pancreatic remanent volume, which is considered a marker for PEI could not be evaluated. Pancreatic enzyme replacement therapy (PERT) was not associated with NAFLD. CONCLUSION: Numerous factors are associated with NAFLD after pancreatectomy. Previous research shows that PEI may be associated with NAFLD; however, this could not be compared in our meta-analysis. Further research is required to study the role of PERT in NAFLD.

Understanding surgical attrition for "resectable" pancreatic cancer.

OBJECTIVES: We used a novel combined analysis to evaluate various factors associated with failure to undergo surgery in non-metastatic pancreatic cancer. METHODS: We identified rates of surgery and reasons for surgical attrition from clinical trials, which studied neoadjuvant therapy in resectable pancreatic cancer. Next, we queried the National Cancer Database (NCDB) for Stage I-III, T1-3 pancreatic adenocarcinoma patients. We investigated the rates and factors associated with the receipt of surgery. Finally, we evaluated variable importance predicting the receipt of surgery. RESULTS: In clinical trials, 25-30 % of patients did not undergo surgery, mostly due to disease progression. In the NCDB, the overall surgical rate was only 49 %, but increased to 67 % in a curated cohort meant to mirror clinical trial patients. Patients treated at low-volume institutions (OR = 0.64, 95 % CI: 0.61-0.67) and who were uninsured (OR = 0.56, 95 % CI: 0.52-0.62) and Medicaid-insured (OR = 0.67, 95 % CI: 0.64-0.71) were less likely to receive potentially curative surgery. CONCLUSION: We have identified a realistic target surgery rate of 70%-75 % in potentially-resectable pancreatic cancer. While attrition to pancreatic cancer surgery is mostly due to tumor biology, our study identified the most important non-medical barriers, such as facility volume and insurance, affecting pancreatic cancer surgery.

Extended antibiotic therapy is associated with a lower rate of clinically relevant postoperative pancreatic fistula after pancreatoduodenectomy in intermediate- and high-risk patients: A single-institution analysis.

BACKGROUND: Clinically relevant postoperative pancreatic fistula remains a common complication after pancreatoduodenectomy. The fistula risk score is a validated tool to predict the risk of clinically relevant postoperative pancreatic fistula. To mitigate complications, we have implemented an extended antibiotic pathway for patients at increased risk of clinically relevant postoperative pancreatic fistula (fistula risk score ≥3). We report outcomes after pancreatoduodenectomy in patients at increased risk for clinically relevant postoperative pancreatic fistula who received extended antibiotic therapy compared to those who received standard perioperative antibiotics (single dose before incision). METHODS: Single-institution analysis of 87 patients who underwent elective pancreatoduodenectomy (2018-2022) with soft gland texture and fistula risk score ≥3 and were treated with (n = 34) or without (n = 53) 10 days of broad-spectrum antibiotics (piperacillin/tazobactam converted to amoxicillin/clavulanic acid at discharge) after surgery. Associations between extended antibiotics and postoperative outcomes were analyzed. RESULTS: Baseline clinicodemographic factors were similar between cohorts. Patients who received extended antibiotics had shorter index days (6 vs 8 days, P = .004) and 90-day composite length of stay (8.5 vs 12 days, P = .018). Patients who received extended antibiotics had lower rates of clinically relevant postoperative pancreatic fistula (11.8% vs 37.7%; odds ratio = 0.17, 95% confidence interval: 0.04-0.68), wound infections (8.8% vs 30.2%; odds ratio = 0.08, 95% confidence interval: 0.01-0.50), organ space infections (14.7% vs 43.4%; odds ratio = 0.15, 95% confidence interval: 0.04-0.52), and image-guided drain placement (8.8% vs 34.0%; odds ratio = 0.15, 95% confidence interval: 0.04-0.62). There were no Clostridium difficile infections in the extended antibiotic group. CONCLUSION: Extended antibiotic therapy is associated with a lower rate of clinically relevant postoperative pancreatic fistula and associated complications after pancreatoduodenectomy in patients with a fistula risk score ≥3. These results form the basis of a randomized controlled trial (NCT05753735).

Surgical Resection Alone is Associated With Higher Long-Term Survival Than Multiagent Chemotherapy Alone for Patients With Localized Biliary Tract Cancers.

INTRODUCTION: We compared long-term survival of patients with localized biliary tract cancers (BTCs) treated with either surgical resection or multiagent chemotherapy. METHODS: Patients with localized BTC [gallbladder adenocarcinoma, extrahepatic cholangiocarcinoma, intrahepatic cholangiocarcinoma] were identified within the National Cancer Database (2010-2017). Piecewise-constant hazard modeling was used to estimate hazard ratios (HRs) at prespecified intervals: 0-30 d, 31-60 d, 61-90 d, and >90 d post-treatment. RESULTS: A total of 5988 patients with localized BTC were identified: 2697 (45.0%) received multiagent chemotherapy and 3291 (55.0%) underwent surgical resection. Patients with gallbladder adenocarcinoma or extrahepatic cholangiocarcinoma who were treated with surgical resection had an associated decline in overall survival (OS) as compared to those treated with multiagent chemotherapy within 0-30 d of treatment initiation (gallbladder adenocarcinoma [adjusted HR = 3.94, 95% confidence interval [CI]: 1.77-8.80]; extrahepatic cholangiocarcinoma [adjusted HR = 4.88, 95% CI: 2.76-8.61]). However, there was an associated improvement in OS for patients treated with surgical resection after 90 d from treatment initiation (gallbladder adenocarcinoma [adjusted HR = 0.36, 95% CI: 0.28-0.46]; extrahepatic cholangiocarcinoma [adjusted HR = 0.27, 95% CI: 0.24-0.32]). Among patients with intrahepatic cholangiocarcinoma, those who underwent surgical resection had an associated improvement in OS at 31-60 d (adjusted HR = 0.63, 95% CI: 0.40-0.99) and a further associated increase in OS at 61-90 d (adjusted HR = 0.34, 95% CI: 0.21-0.54) and after 90 d (HR = 0.23, 95% CI: 0.21-0.27) of treatment initiation. CONCLUSIONS: For patients with localized BTC, surgical resection alone is associated with improved long-term survival outcomes compared to multiagent chemotherapy alone.

Differences in the surgical management of early-stage hepatocellular carcinoma at minority versus non-minority-serving hospitals.

BACKGROUND: We examined differences in surgical intervention at minority-serving hospitals versus non-minority-serving hospitals among patients with early-stage hepatocellular carcinoma. We also investigated associations between surgical management and overall survival, stratified by minority-serving hospital status. METHODS: Patients with early-stage hepatocellular carcinoma, defined as cT1, were identified within the National Cancer Database (2004-2018). The primary outcome was surgical intervention (resection, ablation, or transplantation). The proportion of minority (non-Hispanic Black or Hispanic) patients treated at each facility was determined, and hospitals in the top decile were considered minority-serving hospitals. RESULTS: A total of 46,703 patients with early-stage hepatocellular carcinoma were identified, of whom 4,214 (9.0%) were treated at minority-serving hospitals. Patients treated at minority-serving hospitals were less likely to undergo surgical intervention than patients treated at non-minority-serving hospitals (odds ratio = 0.87, 95% confidence interval: 0.81-0.94). Minority patients treated at non-minority-serving hospitals were less likely to undergo surgical intervention than White patients (odds ratio = 0.86, 95% confidence interval: 0.82-0.90) and had a further associated decrease in the likelihood of surgical intervention when treated at minority-serving hospitals (odds ratio = 0.81, 95% confidence interval: 0.69-0.94). Regardless of minority-serving hospital status, surgery was associated with improved overall survival. There were no clinically meaningful differences in overall survival between White and minority patients who underwent surgery either at minority-serving hospitals or non-minority-serving hospitals. CONCLUSIONS: Patients with early-stage hepatocellular carcinoma had an associated decrease in the likelihood of surgical intervention when treated at minority-serving hospitals. Minority patients treated at minority-serving hospitals had an associated decrease in the likelihood of surgery, but to a lesser extent when treated at non-minority-serving hospitals. Surgery was associated with improved overall survival regardless of minority or minority-serving hospital status.

Disparities in guideline-compliant care for patients with pancreatic ductal adenocarcinoma at minority-versus non-minority-serving hospitals.

BACKGROUND: We examined disparities in guideline-compliant care at minority-serving hospitals (MSH) versus non-MSH among patients with localized or metastatic pancreatic adenocarcinoma (PDAC). METHODS: Patients with PDAC were identified within the National Cancer Database (2004-2018). Guideline-compliant care was defined as surgery + chemotherapy ± radiation therapy for localized and chemotherapy for metastatic disease. Facilities in the top decile of minority patients treated were considered MSH. RESULTS: A total of 190,950 patients were identified and most (59.6%) had metastatic disease. Overall, 6.4% of patients with localized and 8.2% of patients with metastatic disease were treated at MSH. Patients treated at MSH were less likely to receive guideline-compliant care (localized: OR = 0.78, 95% CI: 0.67-0.91; metastatic: OR = 0.77, 95% CI: 0.67-0.88). Minority patients were less likely to receive guideline-compliant care at non-MSH (localized: OR = 0.71, 95% CI: 0.67-0.75; metastatic: OR = 0.85, 95% CI: 0.82-0.89) or MSH (localized: OR = 0.85, 95% CI: 0.74-0.98; metastatic: OR = 0.91, 95% CI: 0.82-0.99). Patients treated at non-MSH or MSH who received guideline-compliant care were more likely to have higher OS regardless of stage or race. CONCLUSIONS: MSH patients were less likely to receive guideline-compliant care and minority patients were less likely to receive guideline-compliant care regardless of MSH status. Guideline-compliant care was associated with improved OS.

Trends in and Prognostic Significance of Time to Treatment in Pancreatic Cancer: A Population-Based Study.

INTRODUCTION: The association of time to treatment (TTT) with survival remains unclear in pancreatic adenocarcinoma (PDAC). In this study, we evaluate the recent trends in TTT, causes for delay, and its effect on survival. METHODS: We included patients with PDAC of all stages from the National Cancer Database (2004-2020) who underwent either surgery or chemotherapy/radiotherapy (CT/RT). TTT was defined as the duration between tissue diagnosis and first treatment. Linear regression (ß) was used to study the temporal trends in time delay. RESULTS: A total of 239,638 patients were included. The median TTT was 25 days. Using multivariable analysis, we found that increasing age (OR 1.48), female gender (OR 1.04), Black race (OR 1.3), lower educational status (OR 1.2), Medicaid, Medicare insurance, and uninsured (OR 1.2, 1.5, and 1.2, respectively), treatment at academic centers (OR 1.3), higher Charlson-Deyo comorbidity index (OR 1.2), and CT/RT (OR 1.5) were associated with increased TTT. There was a steady rise in median TTT from 21 to 28 days between 2004 and 2020 (ß = 0.3), suggestive of a worsening trend. Concurrently, there was an increasing trend in utilization of neoadjuvant CT/RT between 2004 and 2020 in early-stage PDAC. On Cox regression, TTT delay was associated with poor overall survival in stage I-IV patients (HR 1.1, 1.1, 1.09, and 1.53, respectively). CONCLUSIONS: Delayed treatment approaching 2 months was observed in 10% of the population. The rising temporal trend in TTT may be attributed to the increasing shift toward neoadjuvant CT/RT in early-stage PDAC and/or the increasing use of tissue biopsy prior to surgery.

Increased glucose availability sensitizes pancreatic cancer to chemotherapy.

Pancreatic Ductal Adenocarcinoma (PDAC) is highly resistant to chemotherapy. Effective alternative therapies have yet to emerge, as chemotherapy remains the best available systemic treatment. However, the discovery of safe and available adjuncts to enhance chemotherapeutic efficacy can still improve survival outcomes. We show that a hyperglycemic state substantially enhances the efficacy of conventional single- and multi-agent chemotherapy regimens against PDAC. Molecular analyses of tumors exposed to high glucose levels reveal that the expression of GCLC (glutamate-cysteine ligase catalytic subunit), a key component of glutathione biosynthesis, is diminished, which in turn augments oxidative anti-tumor damage by chemotherapy. Inhibition of GCLC phenocopies the suppressive effect of forced hyperglycemia in mouse models of PDAC, while rescuing this pathway mitigates anti-tumor effects observed with chemotherapy and high glucose.

Targeting wild-type IDH1 enhances chemosensitivity in pancreatic cancer.

Pancreatic cancer (PC) is one of the most aggressive types of cancer, with a five-year overall survival rate of 11% among all-comers. Current systemic therapeutic options are limited to cytotoxic chemotherapies which have limited clinical efficacy and are often associated with development of drug resistance. Analysis of The Cancer Genome Atlas showed that wild-type isocitrate dehydrogenase (wtIDH1) is overexpressed in pancreatic tumors. In this study, we focus on the potential roles of wtIDH1 in pancreatic cancer chemoresistance. We found that treatment of pancreatic cancer cells with chemotherapy induced expression of wtIDH1, and this serves as a key resistance factor. The enzyme is protective to cancer cells under chemotherapy-induced oxidative stress by producing NADPH and alpha-ketoglutarate to maintain redox balance and mitochondrial function. An FDA-approved mutant IDH1 inhibitor, ivosidenib (AG-120), is actually a potent wtDH1 inhibitor under a nutrient-deprived microenvironment, reflective of the pancreatic cancer microenvironment. Suppression of wtIDH1 impairs redox balance, results in increased ROS levels, and enhances chemotherapy induced apoptosis in pancreatic cancer vis ROS damage in vitro. In vivo experiments further revealed that inhibiting wtIDH1 enhances chemotherapy anti-tumor effects in patient-derived xenografts and murine models of pancreatic cancer. Pharmacologic wtIDH1 inhibition with ivosidenib represents an attractive option for combination therapies with cytotoxic chemotherapy for patients with pancreatic cancer. Based on these data, we have initiated phase Ib trial combining ivosidenib and multi-agent chemotherapy in patients with pancreatic cancer (NCT05209074).

Discordance Between Conventional and Detailed Lymph Node Analysis in Resected, Node-negative Pancreatic or Ampullary Adenocarcinomas and Association With Adverse Survival Outcomes: A Single-institution Analysis.

OBJECTIVE: To assess the frequency of occult metastases (OM) in patients with resected pancreatic ductal adenocarcinoma (PDAC) or ampullary adenocarcinoma (AA) discovered on detailed pathologic examination on lymph nodes (LNs) previously considered negative by conventional analysis and to examine the association between OM and overall survival (OS). BACKGROUND: Poor prognosis of patients with no pathologic evidence of LN metastases may be due to OM that is not detected on conventional LN analysis. METHODS: Patients with LN-negative resected PDAC or AA (2010-2020) were identified from our institutional database. Original hematoxylin and eosin ( H and E ) slides were reanalyzed. In addition, selected LN were analyzed by H and E (3 sections/LN) and pan-cytokeratin (AE1-AE3/PCK26) immunohistochemistry. RESULTS: A total of 598 LNs from 74 LN-negative patients were reexamined. Nineteen patients (25.7%) had OM; 9 (47.4%) were found with immunohistochemistry but not on H and E . The number of positive LNs ranged from 1 to 3. No clinicodemographic, pathologic, or treatment-related factors were associated with OM. On conventional LN analysis, 3/19 patients (15.8%) had stage IA, 9/34 (26.5%) had stage IB, and 7/19 (36.8%) had stage IIA. On detailed LN analysis, 11/19 patients (57.9%) were upstaged to IIB, whereas 8/19 (42.1%) had isolated tumor cells only (N0i+). OM was associated with shorter OS (median OS: 22.3 vs 50.5 months; hazard ratio=3.95, 95% CI: 1.58-9.86). CONCLUSIONS: There is a 26% discordance rate between conventional and detailed LN pathologic analysis in resected PDAC and AA. The presence of OM is associated with shorter OS.

An analysis of time to treatment in patients with pancreatic adenocarcinoma.

BACKGROUND: Currently, no guidelines exist regarding the appropriate time from diagnosis to treatment among pancreatic adenocarcinoma patients. Herein, we aim to define the median time to treatment in pancreatic adenocarcinoma, factors associated with treatment delay, and prognostic significance. METHODS: We conducted a retrospective study of pancreatic adenocarcinoma patients, stage I-IV, at a tertiary referral center (2017-2020). We subdivided time to treatment (days) into 4 components: (1) Ti: symptom onset to initial provider evaluation, (2) Tii: initial provider evaluation to diagnosis, (3) Tiii: diagnosis to specialist consultation, (4) Tiv: specialist visit to treatment. RESULTS: In total, 217 patients met the inclusion criteria. The median Ti, Tii, Tiii, and Tiv were 20, 12, 4, and 14 days, respectively. The total time to treatment was 75 days. Patients with weight loss had longer Ti (ß = 108.6). More frequent hospitalizations (ß = 19.5) and misdiagnosis (ß = 33.4) were associated with longer Tii. Patients with a history of malignancy (ß = 15) or active treatment of a second disease (ß = 19.4) had longer Tiii. Poor performance status (ß = 6.2) or private insurance (ß = 50.2) were associated with a longer Tiv. Black patients had longer Ti+ii+iii+iv (ß = 100). Time to treatment was not associated with overall survival (P > .05). CONCLUSION: It takes a median time of less than a month for a patient with pancreatic adenocarcinoma to start treatment, even after they visit a primary provider. The greatest opportunity to shorten the overall time to treatment is by having patients seek medical attention earlier (Ti).

Early Postoperative Vital Signs Predict Subsequent 90-Day Mortality After Pancreaticoduodenectomy.

BACKGROUND: While complication rates after pancreaticoduodenectomy (PD) have improved in recent decades, surgical-related death remains a possibility. Postoperative vital signs offer an untapped opportunity to identify predictors of 90-day mortality. METHODS: We performed a retrospective chart review interrogating postoperative day (POD 0-7) vital sign measurements from patients undergoing a PD at Thomas Jefferson University Hospital, Philadelphia, PA (2009-2014). Five specific vital signs were examined as predictors of mortality: temperature, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure. Statistical analyses and logic algorithms were employed to rank vital sign parameters, with cut-points, to identify those associated with the highest risk of mortality and the most clinical relevance. RESULTS: In our cohort, 11/750 patients (1.5%) died within 30 days of surgery, and 21/750 patients (2.8%) died within 90 days of surgery. Vital sign perturbations associated with the highest risk of mortality included mean SBP < 95 mmHg on POD 7 (odds ratio 51.46) and the mean temperature < 96.9℉ on POD 3 (odds ratio 22.63) with specificities exceeding 99%. The most clinically relevant predictor (i.e., a higher sensitivity) was DBP < 60.5 mmHg on POD 7 (odds ratio 12.45, sensitivity of 75%). These predictors remained statistically significant in a multivariable model. CONCLUSIONS: Vital signs can be more effectively utilized to predict 90-day mortality after pancreaticoduodenectomy. Values beyond an informative threshold can potentially identify patients for more intensive monitoring with a goal of rescuing patients and preventing death.

Why the Treatment Sequence Matters: Interplay Between Chemotherapy Cycles Received, Cumulative Dose Intensity, and Survival in Resected Early-stage Pancreas Cancer.

OBJECTIVE: To define the optimal threshold of perioperative chemotherapy completion and relative dose intensity (RDI) for patients with resected pancreatic ductal adenocarcinoma (PDAC). BACKGROUND: Many patients who undergo pancreatectomy for PDAC fail to initiate or complete recommended perioperative chemotherapy. The association between the amount of perioperative chemotherapy received and overall survival (OS) is not well-defined. METHODS: Single-institution analysis of 225 patients who underwent pancreatectomy for stage I/II PDAC (2010-2021). Associations between OS, chemotherapy cycles completed, and RDI were analyzed. RESULTS: Regardless of treatment sequence, completion of ≥67% of recommended cycles was associated with improved OS compared with no chemotherapy [median OS: 34.5 vs 18.1 months; hazard ratio (HR): 0.43; 95% CI: 0.25-0.74] and <67% of cycles (median OS: 17.9 months; HR: 0.39; 95% CI: 0.24-0.64). A near-linear relationship existed between cycles completed and the RDI received (ß = 0.82). A median RDI of 56% corresponded to the completion of 67% of cycles. Receipt of ≥56% RDI was associated with improved OS compared with no chemotherapy (median OS: 35.5 vs 18.1 months; HR: 0.44; 95% CI: 0.23-0.84) and <56% RDI (median OS: 27.2 months; HR: 0.44; 95% CI: 0.20-0.96). Neoadjuvant chemotherapy is associated with increased odds of receiving ≥67% of recommended cycles (odds ratio: 2.94; 95% CI: 1.45-6.26) and ≥56% RDI (odds ratio: 4.47; 95% CI: 1.72-12.50). CONCLUSIONS: Patients with PDAC who received ≥67% of recommended chemotherapy cycles or ≥56% cumulative RDI had improved OS. Neoadjuvant therapy was associated with increased odds of receiving ≥67% of cycles and ≥56% cumulative RDI and should be considered in all patients with resectable PDAC.

Understanding Disparities in Receipt of Complex Gastrointestinal Cancer Surgery at a Small Geographic Scale.

OBJECTIVE: To define neighborhood-level disparities in the receipt of complex cancer surgery. BACKGROUND: Little is known about the geographic variation of receipt of surgery among patients with complex gastrointestinal (GI) cancers, especially at a small geographic scale. METHODS: This study included individuals diagnosed with 5 invasive, nonmetastatic, complex GI cancers (esophagus, stomach, pancreas, bile ducts, liver) from the Ohio Cancer Incidence Surveillance System during 2009 and 2018. To preserve patient privacy, we combined US census tracts into the smallest geographic areas that included a minimum number of surgery cases (n=11) using the Max-p-regions method and called these new areas "MaxTracts." Age-adjusted surgery rates were calculated for MaxTracts, and the Hot Spot analysis identified clusters of high and low surgery rates. US Census and CDC PLACES were used to compare neighborhood characteristics between the high- and low-surgery clusters. RESULTS: This study included 33,091 individuals with complex GI cancers located in 1006 MaxTracts throughout Ohio. The proportion in each MaxTract receiving surgery ranged from 20.7% to 92.3% with a median (interquartile range) of 48.9% (42.4-56.3). Low-surgery clusters were mostly in urban cores and the Appalachian region, whereas high-surgery clusters were mostly in suburbs. Low-surgery clusters differed from high-surgery clusters in several ways, including higher rates of poverty (23% vs. 12%), fewer married households (40% vs. 50%), and more tobacco use (25% vs. 19%; all P <0.01). CONCLUSIONS: This improved understanding of neighborhood-level variation in receipt of potentially curative surgery will guide future outreach and community-based interventions to reduce treatment disparities. Similar methods can be used to target other treatment phases and other cancers.

Assessing the use of Extended Venous Thromboembolism Prophylaxis on the Rates of Venous Thromboembolism and Postpancreatectomy Hemorrhage Following Pancreatectomy for Malignancy.

OBJECTIVE: To compare rates of venous thromboembolism (VTE) and postpancreatectomy hemorrhage (PPH) in patients with pancreatic or periampullary malignancy preimplementation and postimplementation of routine extended VTE prophylaxis. BACKGROUND: Guidelines recommend up to 28 days of VTE prophylaxis following major abdominal cancer operations. There is a paucity of data examining rates of VTE and PPH in patients who receive extended VTE prophylaxis following pancreatectomy. METHODS: Single-institution analysis of patients who underwent pancreatectomy for malignancy (2004-2021). VTE and PPH rates within 90 days of discharge were compared based on receipt of extended VTE prophylaxis with enoxaparin. RESULTS: A total of 478 patients were included. Twenty-two (4.6%) patients developed a postoperative VTE, 12 (2.5%) of which occurred postdischarge. Twenty-five (5.2%) patients experienced PPH, 13 (2.7%) of which occurred postdischarge. There was no associated difference in the development of postdischarge VTE between patients who received extended VTE prophylaxis and those who did not (2.3% vs 2.8%, P =0.99). There was no associated difference in the rate of postdischarge PPH between patients who received extended VTE prophylaxis and those who did not (3.4% vs 1.9%, P =0.43). In the subset of patients on antiplatelet agents, the addition of enoxaparin did not appear to be associated with higher VTE (3.9 vs. 0%, P =0.31) or PPH (3.0 vs. 4.5%, P =0.64) rates. CONCLUSIONS: Extended VTE prophylaxis following pancreatectomy for malignancy was not associated with differences in postdischarge VTE and PPH rates. These data suggest extended VTE prophylaxis is safe but may not be necessary for all patients following pancreatectomy.