Acid Suspends the Circadian Clock in Hypoxia through Inhibition of mTOR.

Recent reports indicate that hypoxia influences the circadian clock through the transcriptional activities of hypoxia-inducible factors (HIFs) at clock genes. Unexpectedly, we uncover a profound disruption of the circadian clock and diurnal transcriptome when hypoxic cells are permitted to acidify to recapitulate the tumor microenvironment. Buffering against acidification or inhibiting lactic acid production fully rescues circadian oscillation. Acidification of several human and murine cell lines, as well as primary murine T cells, suppresses mechanistic target of rapamycin complex 1 (mTORC1) signaling, a key regulator of translation in response to metabolic status. We find that acid drives peripheral redistribution of normally perinuclear lysosomes away from perinuclear RHEB, thereby inhibiting the activity of lysosome-bound mTOR. Restoring mTORC1 signaling and the translation it governs rescues clock oscillation. Our findings thus reveal a model in which acid produced during the cellular metabolic response to hypoxia suppresses the circadian clock through diminished translation of clock constituents.

Stromal changes in the aged lung induce an emergence from melanoma dormancy.

Disseminated cancer cells from primary tumours can seed in distal tissues, but may take several years to form overt metastases, a phenomenon that is termed tumour dormancy. Despite its importance in metastasis and residual disease, few studies have been able to successfully characterize dormancy within melanoma. Here we show that the aged lung microenvironment facilitates a permissive niche for efficient outgrowth of dormant disseminated cancer cells-in contrast to the aged skin, in which age-related changes suppress melanoma growth but drive dissemination. These microenvironmental complexities can be explained by the phenotype switching model, which argues that melanoma cells switch between a proliferative cell state and a slower-cycling, invasive state1-3. It was previously shown that dermal fibroblasts promote phenotype switching in melanoma during ageing4-8. We now identify WNT5A as an activator of dormancy in melanoma disseminated cancer cells within the lung, which initially enables the efficient dissemination and seeding of melanoma cells in metastatic niches. Age-induced reprogramming of lung fibroblasts increases their secretion of the soluble WNT antagonist sFRP1, which inhibits WNT5A in melanoma cells and thereby enables efficient metastatic outgrowth. We also identify the tyrosine kinase receptors AXL and MER as promoting a dormancy-to-reactivation axis within melanoma cells. Overall, we find that age-induced changes in distal metastatic microenvironments promote the efficient reactivation of dormant melanoma cells in the lung.

Paradoxical Role for Wild-Type p53 in Driving Therapy Resistance in Melanoma.

Metastatic melanoma is an aggressive disease, despite recent improvements in therapy. Eradicating all melanoma cells even in drug-sensitive tumors is unsuccessful in patients because a subset of cells can transition to a slow-cycling state, rendering them resistant to most targeted therapy. It is still unclear what pathways define these subpopulations and promote this resistant phenotype. In the current study, we show that Wnt5A, a non-canonical Wnt ligand that drives a metastatic, therapy-resistant phenotype, stabilizes the half-life of p53 and uses p53 to initiate a slow-cycling state following stress (DNA damage, targeted therapy, and aging). Inhibiting p53 blocks the slow-cycling phenotype and sensitizes melanoma cells to BRAF/MEK inhibition. In vivo, this can be accomplished with a single dose of p53 inhibitor at the commencement of BRAF/MEK inhibitor therapy. These data suggest that taking the paradoxical approach of inhibiting rather than activating wild-type p53 may sensitize previously resistant metastatic melanoma cells to therapy.

Does Hospital Operative Volume Influence the Outcomes of Patients After Heated Intraperitoneal Chemotherapy for Peritoneal Carcinomatosis?

BACKGROUND: For some cancer operations, center volume is associated with improved patient outcomes. Whether this association is true for cytoreductive surgery/heated intraperitoneal chemotherapy (CRS/HIPEC) is unclear. Given the rapidly expanding use of CRS/HIPEC, the aim of this analysis was to determine whether a volume-outcome relationship exists for this strategy. METHODS: The Vizient Clinical Database® was queried for CRS/HIPEC cases from January 2020 through December 2022. Low-, medium-, and high-volume designations were made by sorting hospitals by case volume and creating equal tertiles based on total number of cases. Analysis was performed via one-way ANOVA with post-hoc Tukey test, as indicated. RESULTS: In the 36-month study period, 5165 cases were identified across 149 hospitals. Low- (n = 113), medium- (n = 25), and high-volume (n = 11) centers performed a median of 4, 21, and 47 cases per annum, respectively. Most cases were performed for appendiceal (39.3%) followed by gynecologic neoplasms (20.4%). Groups were similar with respect to age, gender, race, comorbidities, and histology. Low-volume centers were more likely to utilize the ICU post-operatively (59.6% vs. 40.5% vs. 36.3%; p = 0.02). No differences were observed in morbidity (9.4% vs. 7.1% vs. 9.0%, p = 0.71), mortality (0.9% vs. 0.6% vs. 0.7%, p = 0.93), length of stay (9.3 vs. 9.4 vs. 10 days, p = 0.83), 30-day readmissions (5.6% vs. 5.6% vs. 5.6%, p = 1.0), or total cost among groups. CONCLUSIONS: No association was found between CRS/HIPEC hospital volume and post-operative outcomes. These data suggest that in academic medical centers with HIPEC programs, outcomes for commonly treated cancers are not associated with hospital volume.

Extent of Resection and Long-Term Outcomes for Appendiceal Adenocarcinoma: a SEER Database Analysis of Mucinous and non-Mucinous Histologies.

BACKGROUND: Mucinous appendiceal adenocarcinomas (MAA) and non-mucinous appendiceal adenocarcinomas (NMAA) demonstrate differences in rates and patterns of recurrence, which may inform the appropriate extent of surgical resection (i.e., appendectomy versus colectomy). The impact of extent of resection on disease-specific survival (DSS) for each histologic subtype was assessed. PATIENTS AND METHODS: Patients with resected, non-metastatic MAA and NMAA were identified in the Surveillance, Epidemiology, and End Results database (2000-2020). Multivariable models were created to examine predictors of colectomy for each histologic subtype. DSS was calculated using Kaplan-Meier estimates and examined using Cox proportional hazards modeling. RESULTS: Among 4674 patients (MAA: n = 1990, 42.6%; NMAA: n = 2684, 57.4%), the majority (67.8%) underwent colectomy. Among colectomy patients, the rate of nodal positivity increased with higher T-stage (MAA: T1: 4.6%, T2: 4.0%, T3: 17.1%, T4: 21.6%, p < 0.001; NMAA: T1: 6.8%, T2: 11.4%, T3: 25.6%, T4: 43.8%, p < 0.001) and higher tumor grade (MAA: well differentiated: 7.7%, moderately differentiated: 19.2%, and poorly differentiated: 31.3%; NMAA: well differentiated: 9.0%, moderately differentiated: 20.5%, and 44.4%; p < 0.001). Nodal positivity was more frequently observed in NMAA (27.6% versus 16.4%, p < 0.001). Utilization of colectomy was associated with improved DSS for NMAA patients with T2 (log rank p = 0.095) and T3 (log rank p = 0.018) tumors as well as moderately differentiated histology (log rank p = 0.006). Utilization of colectomy was not associated with improved DSS for MAA patients, which was confirmed in a multivariable model for T-stage, grade, and use of adjuvant chemotherapy [hazard ratio (HR) 1.00, 95% confidence interval (CI) 0.81-1.22]. CONCLUSIONS: Colectomy was associated with improved DSS for patients with NMAA but not MAA. Colectomy for MAA may not be required.

Segmental Versus Diffuse Main Duct Intraductal Papillary Mucinous Neoplasm: Examination of Main Pancreatic Duct Morphology and Implications for Malignancy Risk and Extent of Surgical Resection.

OBJECTIVE: To determine whether the morphologic features of the main pancreatic duct (MPD) of main-duct-involved-intraductal papillary mucinous neoplasm (IPMN) (ie, main duct or mixed main duct/side branch) have implications for the risk of malignancy and extent of resection. BACKGROUND: International consensus guidelines acknowledge the presence of various MPD morphologies (ie, diffuse vs segmental main-duct-involved-IPMN) without a precise definition of each entity and with limited data to guide treatment strategy. METHODS: All consecutive main-duct-involved-IPMN patients (2005-2019) with a MPD diameter ≥5 mm by cross-sectional imaging were reviewed from a prospective institutional database. Morphologic features of the MPD were correlated with the identification of high-grade dysplasia or pancreatic ductal adenocarcinoma (HGD/PDAC) by logistic regression modeling. In patients who underwent partial pancreatectomy, preoperative MPD morphologic features were correlated with the future development of HGD/PDAC in the pancreatic remnant by Cox hazards modeling. RESULTS: In a cohort of 214 main-duct-involved-IPMN patients, the overall rate of HGD/PDAC was 54.2%. MPD morphologic characteristics associated with HGD/PDAC included: maximal MPD diameter (5-10 mm: 29.8%; 10-14 mm: 59.0%; 15-19 mm: 78.6%; ≥20 mm: 95.8%; P <0.001), segmental extent of maximal dilation (<25%: 28.2%; 25%-49%: 54.9%; 50%-74%: 63.1%; ≥75%: 67.9%; P =0.002), and nonsegmental MPD diameter (<5 mm: 21.5% vs ≥5 mm: 78.5%, P <0.001). Diffuse MPD dilation involving ≥90% extent was rare (5.6%). After a median follow-up of 50 months, 7 (7.2%) patients who underwent partial pancreatectomy for IPMN without associated PDAC developed HGD/PDAC in the pancreatic remnant. Maximal MPD diameter, segmental extent of maximal dilation, or nonsegmental MPD diameter were not associated with the development of HGD/PDAC in the pancreatic remnant. However, a mural nodule on preoperative imaging was associated with the development of HGD/PDAC in the pancreatic remnant. CONCLUSIONS: "Diffuse" involvement with homogenous dilation of the MPD was rare. For the majority of patients with segmental main-duct-involved-IPMN, the MPD morphology conferred malignancy risk. Duct morphology was not predictive for the development of HGD or invasive disease in the pancreatic remnant, implying the safety of limited pancreatic resection for initial surgical management.

Recurrence-free survival versus overall survival as a primary endpoint for studies of resected colorectal liver metastasis: a retrospective study and meta-analysis.

BACKGROUND: Recurrence-free survival has been used as a surrogate endpoint for overall survival in trials involving patients with resected colorectal liver metastases. We aimed to assess the correlation between recurrence-free survival and overall survival after resection of colorectal liver metastases to determine the adequacy of this surrogate endpoint. METHODS: In this retrospective study and meta-analysis, we compiled an institutional cohort of consecutive patients who had complete resection of colorectal liver metastases from the Memorial Sloan Kettering Cancer Center (New York, NY, USA) prospective database. Patients were eligible for inclusion if they were aged 18 years or older, and underwent hepatectomy, with or without operative ablation, between Jan 1, 1991, and April 30, 2019. We estimated overall survival and recurrence-free survival probabilities at various timepoints using the Kaplan-Meier method, and we assessed pairwise associations between these endpoints using Spearman's rank correlation. We also did a meta-analysis of adjuvant phase 3 clinical trials for colorectal liver metastases to assess the correlation between hazard ratios (HRs) for recurrence-free survival and overall survival. We searched MEDLINE for articles of phase 3 randomised controlled trials analysing adjuvant treatment strategies for resected colorectal metastases from database inception to Jan 1, 2022. The titles and abstracts of identified studies were screened before full-text screening and summary data were either recalculated or extracted manually from the published Kaplan-Meier curves (depending on data availability). FINDINGS: Data were available for 3299 patients in the institutional database, of whom 2983 were eligible for inclusion in our cohort. Median follow-up was 8·4 years (95% CI 7·9-9·1) , during which time there were 1995 (67%) disease recurrences and 1684 (56%) deaths. Median recurrence-free survival was 1·3 years (95% CI 1·3-1·4) and median overall survival was 5·2 years (95% CI 5·0-5·5). 1428 (85%) of 1684 deaths were preceded by recurrence, and median time from recurrence to death was 2·0 years (IQR 1·0-3·4). Pairwise correlations between recurrence-free survival and overall survival were low to moderate, with a correlation estimate ranging from 0·30 (SD 0·17) to 0·56 (0·13). In the meta-analysis of adjuvant clinical trials, the Spearman's correlation coefficient between recurrence-free survival HR and overall survival HR was r=0·20 (p=0·71). INTERPRETATION: We found a minimal correlation between recurrence-free survival and overall survival after resection of colorectal liver metastases. Recurrence-free survival is an inadequate surrogate endpoint for overall survival in this disease setting. FUNDING: US National Cancer Institute.

Genomic Stratification of Resectable Colorectal Liver Metastasis Patients and Implications for Adjuvant Therapy and Survival.

OBJECTIVE: To determine whether genomic risk groups identified by somatic mutation testing of colorectal liver metastasis (CRLM) can be used for "molecularly-guided" selection for adjuvant systemic chemotherapy and hepatic artery infusion of FUDR (SYS+HAI-FUDR). BACKGROUND: Several genomic biomarkers have been associated with clinical phenotype and survival for patients with resectable CRLM. It is unknown whether prognostication afforded by genomic stratification translates into enhanced patient selection for adjuvant hepatic artery infusion therapy. METHODS: Consecutive patients with resected CRLM and available mutational characterization via Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets were reviewed from a prospective institutional database. Patients were stratified into three genomic risk groups based on previously defined alterations in SMAD4, EGFR and the RAS/RAF pathway. The association between SYS+HAI-FUDR and overall survival, relative to adjuvant chemotherapy alone (SYS), was evaluated in each genomic risk group by Cox proportional hazard regression and propensity score matched analyses. RESULTS: A total of 334 patients (SYS+HAI-FUDR 204; SYS 130) were identified; the rates of RAS/RAF alterations and SMAD4 inactivation were 47.4% and 11.7%, respectively. After a median follow-up of 58 months, adjuvant SYS+HAI-FUDR was independently associated with a reduced risk of death (HR 0.50, 95%CI 0.26-0.98, P = 0.045) in the low-risk genomic group, but not in the moderate-risk (HR 1.07, 95%CI 0.5-2.07, P = 0.749) or high-risk (HR 1.62, 95%CI 0.29-9.12, P = 0.537) cohorts. Following propensity score matching, adjuvant SYS+HAI-FUDR remained associated with significant improvements in long-term survival selectively in the low-risk genomic cohort (5-year actuarial survival: 89% vs. 68%, P = 0.019). CONCLUSIONS: Genomic alterations in RAS/RAF, SMAD4, and EGFR may be useful to guide treatment selection in resectable CRLM patients and warrant external validation and integration in future clinical trial design.

The Fistula Risk Score Catalog: Toward Precision Medicine for Pancreatic Fistula After Pancreatoduodenectomy.

OBJECTIVE: This study aims to present a full spectrum of individual patient presentations of pancreatic fistula risk, and to define the utility of mitigation strategies amongst some of the most prevalent, and vulnerable scenarios surgeons encounter. BACKGROUND: The FRS has been utilized to identify technical strategies associated with reduced CR-POPF incidence across various risk strata. However, risk-stratification using the FRS has never been investigated with greater granularity. By deriving all possible combinations of FRS elements, individualized risk assessment could be utilized for precision medicine purposes. METHODS: FRS profiles and outcomes of 5533 PDs were accrued from 17 international institutions (2003-2019). The FRS was used to derive 80 unique combinations of patient "scenarios." Risk-matched analyses were conducted using a Bonferroni adjustment to identify scenarios with increased vulnerability for CR-POPF occurrence. Subsequently, these scenarios were analyzed using multivariable regression to explore optimal mitigation approaches. RESULTS: The overall CR-POPF rate was 13.6%. All 80 possible scenarios were encountered, with the most frequent being scenario #1 (8.1%) - the only negligible-risk scenario (CR-POPF rate = 0.7%). The moderate-risk zone had the most scenarios (50), patients (N = 3246), CR-POPFs (65.2%), and greatest non-zero discrepancy in CR-POPF rates between scenarios (18-fold). In the risk-matched analysis, 2 scenarios (#59 and 60) displayed increased vulnerability for CR-POPF relative to the moderate-risk zone (both P < 0.001). Multivariable analysis revealed factors associated with CR-POPF in these scenarios: pancreaticogastrostomy reconstruction [odds ratio (OR) 4.67], omission of drain placement (OR 5.51), and prophylactic octreotide (OR 3.09). When comparing the utilization of best practice strategies to patients who did not have these conjointly utilized, there was a significant decrease in CR-POPF (10.7% vs 35.5%, P < 0.001; OR 0.20, 95% confidence interval 0.12-0.33). CONCLUSION: Through this data, a comprehensive fistula risk catalog has been created and the most clinically-impactful scenarios have been discerned. Focusing on individual scenarios provides a practical way to approach precision medicine, allowing for more directed and efficient management of CR-POPF.

Registry-based randomized clinical trials in surgery: Working with ACS-NSQIP and the AHPBA to conduct pragmatic trials.

Randomized controlled trials (RCTs) represent the gold standard for evidence in clinical medicine because of their ability to account for the effects of unmeasured confounders and selection bias by indication. However, their complexity and immense costs limit their application, and thus the availability of high-quality data to guide clinical care. Registry-based RCTs are a type of pragmatic trial that leverages existing registries as a platform for data collection, providing a low-cost alternative for randomized studies. Herein, we describe the tenets of registry RCTs and the development of the first AHPBA/ACS-NSQIP-based registry trial.

Defining the Safety Profile for Performing Pancreatoduodenectomy in the Setting of Hyperbilirubinemia.

BACKGROUND: Hyperbilirubinemia is commonly observed in patients requiring pancreatoduodenectomy (PD). Thus far, literature regarding the danger of operating in the setting of hyperbilirubinemia is equivocal. What remains undefined is at what specific level of bilirubin there is an adverse safety profile for undergoing PD. The aim of this study is to identify the optimal safety profile of patients with hyperbilirubinemia undergoing PD. PATIENTS AND METHODS: The present work analyzed 803 PDs from 2004 to 2018. A generalized additive model was used to determine cutoff values of total serum bilirubin (TB) that were associated with increases in adverse outcomes, including 90-day mortality. Subgroup comparisons and biliary stent-specific analyses were performed for patients with TB below and above the cutoff. RESULTS: TB of 13 mg/dL was associated with an increase in 90-day mortality (P = 0.043) and was the dominant risk factor on multivariate logistic regression [odds ratio (OR) 8.193, P = 0.001]. Increased TB levels were also associated with reoperations, number of complications per patient, and length of stay. Patients with TB greater than or equal to 13 mg/dL (TB ≥ 13) who received successful biliary decompression through stenting had less combined death and serious morbidity (P = 0.048). CONCLUSIONS: Preoperative TB ≥ 13 mg/dL was associated with increased 90-day mortality after PD. Reducing a TB ≥ 13 is generally recommended before proceeding to surgery.

The impact of surgery for metastatic pancreatic neuroendocrine tumor: a contemporary evaluation matching for chromogranin a level.

BACKGROUND: Studies supporting surgical management of metastatic pancreatic neuroendocrine tumor (PNET) are limited by selection bias. Chromogranin A (CgA) has been used as a biomarker for PNET and may reflect disease burden or biology. This study aimed to correlate CgA level with overall survival and to use it to match patients selected for different treatment approaches in an analysis of the impact of surgical management. METHODS: 1478 patients diagnosed with PNET in the National Cancer Database (2004-2014) were retrospectively identified, and logistic regression analyses were used to evaluate associations between the presence of metastatic disease and CgA level. After matching patients by CgA level and other factors predictive of surgical management, Kaplan-Meier survival analysis was performed. RESULTS: Median CgA level was significantly higher in metastatic versus localized PNET(169 ng/mL versus 66 ng/mL, p < 0.001). On multivariate logistic regression, CgA level was predictive of metastatic disease(OR 1.002, p < 0.001) and survival in metastatic and non-metastatic patients. After matching for CgA level, surgery was associated with improved overall survival. DISCUSSION: CgA level is predictive of the presence of distant metastatic disease and overall survival in PNET. When matched by CgA and other predictors of treatment approach, patients with metastatic PNET undergoing surgery have improved survival.

Impact of obesity on breast cancer recurrence and minimal residual disease.

BACKGROUND: Obesity is associated with an increased risk of breast cancer recurrence and cancer death. Recurrent cancers arise from the pool of residual tumor cells, or minimal residual disease (MRD), that survives primary treatment and persists in the host. Whether the association of obesity with recurrence risk is causal is unknown, and the impact of obesity on MRD and breast cancer recurrence has not been reported in humans or in animal models. METHODS: Doxycycline-inducible primary mammary tumors were generated in intact MMTV-rtTA;TetO-HER2/neu (MTB/TAN) mice or orthotopic recipients fed a high-fat diet (HFD; 60% kcal from fat) or a control low-fat diet (LFD; 10% kcal from fat). Following oncogene downregulation and tumor regression, mice were followed for clinical recurrence. Body weight was measured twice weekly and used to segregate HFD mice into obese (i.e., responders) and lean (i.e., nonresponders) study arms, and obesity was correlated with body fat percentage, glucose tolerance (measured using intraperitoneal glucose tolerance tests), serum biomarkers (measured by enzyme-linked immunosorbent assay), and tissue transcriptomics (assessed by RNA sequencing). MRD was quantified by droplet digital PCR. RESULTS: HFD-Obese mice weighed significantly more than HFD-Lean and LFD control mice (p < 0.001) and had increased body fat percentage (p < 0.001). Obese mice exhibited fasting hyperglycemia, hyperinsulinemia, and impaired glucose tolerance, as well as decreased serum levels of adiponectin and increased levels of leptin, resistin, and insulin-like growth factor 1. Tumor recurrence was accelerated in HFD-Obese mice compared with HFD-Lean and LFD control mice (median relapse-free survival 53.0 days vs. 87.0 days vs. 80.0 days, log-rank p < 0.001; HFD-Obese compared with HFD-Lean HR 2.52, 95% CI 1.52-4.16; HFD-Obese compared with LFD HR 2.27, 95% CI 1.42-3.63). HFD-Obese mice harbored a significantly greater number of residual tumor cells than HFD-Lean and LFD mice (12,550 ± 991 vs. 7339 ± 2182 vs. 4793 ± 1618 cells, p < 0.001). CONCLUSION: These studies provide a genetically engineered mouse model for study of the association of diet-induced obesity with breast cancer recurrence. They demonstrate that this model recapitulates physiological changes characteristic of obese patients, establish that the association between obesity and recurrence risk is causal in nature, and suggest that obesity is associated with the increased survival and persistence of residual tumor cells.

Decoding Grade B Pancreatic Fistula: A Clinical and Economical Analysis and Subclassification Proposal.

OBJECTIVE: The aim of this study was to describe characteristics and management approaches for grade B pancreatic fistula (B-POPF) and investigate whether it segregates into distinct subclasses. BACKGROUND: The 2016 ISGPS refined definition of B-POPF is predicated on various postoperative management approaches, ranging from prolonged drainage to interventional procedures, but the spectrum of clinical severity within this entity is yet undefined. METHODS: Pancreatectomies performed at 2 institutions from 2007 to 2016 were reviewed to identify B-POPFs and their treatment strategies. Subclassification of B-POPFs into 3 classes was modeled after the Fistula Accordion Severity Grading System (B1: prolonged drainage only; B2: pharmacologic management; B3: interventional procedures). Clinical and economic outcomes, unique from the ISGPS definition qualifiers, were analyzed across subclasses. RESULTS: B-POPF developed in 320 of 1949 patients (16.4%), and commonly required antibiotics (70.3%), prolonged drainage (67.8%), and enteral/parenteral nutrition (54.7%). Percutaneous drainage occurred in 79 patients (24.7%), always in combination with other strategies. Management of B-POPFs was widely heterogeneous with a median of 2 approaches/patient (range 1 to 6) and 38 various strategy combinations used. Subclasses B1-3 comprised 19.1%, 52.2%, and 28.8% of B-POPFs, respectively, and were associated with progressively worse clinical and economic outcomes. These results were confirmed by multivariable analysis adjusted for clinical and operative factors. Notably, distribution of the B-POPF subclasses was influenced by institution and type of resection (P < 0.001), while clinical/demographic predictors proved elusive. CONCLUSION: B-POPF is a heterogeneous entity, where 3 distinct subclasses with increasing clinical and economic burden can be identified. This classification framework has potential implications for accurate reporting, comparative research, and performance evaluation.

The Beneficial Effects of Minimizing Blood Loss in Pancreatoduodenectomy.

OBJECTIVE: The aim of this study was to elucidate the impact of intraoperative blood loss on outcomes following pancreatoduodenectomy (PD). BACKGROUND: The negative impact of intraoperative blood loss on outcomes in PD has long been suspected but not well characterized, particularly those factors that may be within surgeons' control. METHODS: From 2001 to 2015, 5323 PDs were performed by 62 surgeons from 17 institutions. Estimated blood loss (EBL) was discretized (0 to 300, 301 to 750, 751 to 1300, and >1300 mL) using optimal scaling methodology. Multivariable regression, adjusted for patient, surgeon, and institutional variables, was used to identify associations between EBL and perioperative outcomes. Factors associated with both increased and decreased EBL were elucidated. The relative impact of surgeon-modifiable contributors was estimated through beta coefficient standardization. RESULTS: The median EBL of the series was 400 mL [interquartile range (IQR) 250 to 600]. Intra-, post-, and perioperative transfusion rates were 15.8%, 24.8%, and 37.2%, respectively. Progressive EBL zones correlated with intra- but not postoperative transfusion in a dose-dependent fashion (P < 0.001), with a key threshold of 750 mL EBL (8.14% vs 40.9%; P < 0.001). Increasing blood loss significantly correlated with poor perioperative outcomes. Factors associated with increased EBL were trans-anastomotic stent placement, neoadjuvant chemotherapy, pancreaticogastrostomy reconstruction, multiorgan or vascular resection, and elevated operative time, of which 38.7% of the relative impact was "potentially modifiable" by the surgeon. Conversely, female sex, small duct, soft gland, minimally invasive approach, pylorus-preservation, biological sealant use, and institutional volume (≥67/year) were associated with decreased EBL, of which 13.6% was potentially under the surgeon's influence. CONCLUSION: Minimizing blood loss contributes to fewer intraoperative transfusions and better perioperative outcomes for PD. Improvements might be achieved by targeting modifiable factors that influence EBL.

Identification of an Optimal Cut-off for Drain Fluid Amylase on Postoperative Day 1 for Predicting Clinically Relevant Fistula After Distal Pancreatectomy: A Multi-institutional Analysis and External Validation.

OBJECTIVE: The aim of this study was to investigate the relationship between drain fluid amylase value on the first postoperative day (DFA1) and clinically relevant fistula (CR-POPF) after distal pancreatectomy (DP), and to identify the cut-off of DFA1 that optimizes CR-POPF prediction. BACKGROUND: DFA1 is a well-recognized predictor of CR-POPF after pancreatoduodenectomy, but its role in DP is largely unexplored. METHODS: DFA1 levels were correlated with CR-POPF in 2 independent multi-institutional sets of DP patients: developmental (n = 338; years 2012 to 2017) and validation cohort (n = 166; years 2006 to 2016). Cut-off choice was based on Youden index calculation, and its ability to predict CR-POPF occurrence was tested in a multivariable regression model adjusted for clinical, demographic, operative, and pathological variables. RESULTS: In the developmental set, median DFA1 was 1745 U/L and the CR-POPF rate was 21.9%. DFA1 correlated with CR-POPF with an area under the curve of 0.737 (P < 0.001). A DFA1 of 2000 U/L had the highest Youden index, with 74.3% sensitivity and 62.1% specificity. Patients in the validation cohort displayed different demographic and operative characteristics, lower values of DFA1 (784.5 U/L, P < 0.001), and reduced CR-POPF rate (10.2%, P < 0.001). However, a DFA1 of 2000 U/L had the highest Youden index in this cohort as well, with 64.7% sensitivity and 75.8% specificity. At multivariable analysis, DFA1 ≥2000 U/L was the only factor significantly associated with CR-POPF in both cohorts. CONCLUSION: A DFA1 of 2000 U/L optimizes CR-POPF prediction after DP. These results provide the substrate to define best practices and improve outcomes for patients receiving DP.

Risk Factors and Mitigation Strategies for Pancreatic Fistula After Distal Pancreatectomy: Analysis of 2026 Resections From the International, Multi-institutional Distal Pancreatectomy Study Group.

OBJECTIVE: To identify a clinical fistula risk score following distal pancreatectomy. BACKGROUND: Clinically relevant pancreatic fistula (CR-POPF) following distal pancreatectomy (DP) is a dominant contributor to procedural morbidity, yet risk factors attributable to CR-POPF and effective practices to reduce its occurrence remain elusive. METHODS: This multinational, retrospective study of 2026 DPs involved 52 surgeons at 10 institutions (2001-2016). CR-POPFs were defined by 2016 International Study Group criteria, and risk models generated using stepwise logistic regression analysis were evaluated by c-statistic. Mitigation strategies were assessed by regression modeling while controlling for identified risk factors and treating institution. RESULTS: CR-POPF occurred following 306 (15.1%) DPs. Risk factors independently associated with CR-POPF included: age (<60 yrs: OR 1.42, 95% CI 1.05-1.82), obesity (OR 1.54, 95% CI 1.19-2.12), hypoalbuminenia (OR 1.63, 95% CI 1.06-2.51), the absence of epidural anesthesia (OR 1.59, 95% CI 1.17-2.16), neuroendocrine or nonmalignant pathology (OR 1.56, 95% CI 1.18-2.06), concomitant splenectomy (OR 1.99, 95% CI 1.25-3.17), and vascular resection (OR 2.29, 95% CI 1.25-3.17). After adjusting for inherent risk between cases by multivariable regression, the following were not independently associated with CR-POPF: method of transection, suture ligation of the pancreatic duct, staple size, the use of staple line reinforcement, tissue patches, biologic sealants, or prophylactic octreotide. Intraoperative drainage was associated with a greater fistula rate (OR 2.09, 95% CI 1.51-3.78) but reduced fistula severity (P < 0.001). CONCLUSIONS: From this large analysis of pancreatic fistula following DP, CR-POPF occurrence cannot be reliably predicted. Opportunities for developing a risk score model are limited for performing risk-adjusted analyses of mitigation strategies and surgeon performance.

Alternative Fistula Risk Score for Pancreatoduodenectomy (a-FRS): Design and International External Validation.

OBJECTIVE: The aim of this study was to develop an alternative fistula risk score (a-FRS) for postoperative pancreatic fistula (POPF) after pancreatoduodenectomy, without blood loss as a predictor. BACKGROUND: Blood loss, one of the predictors of the original-FRS, was not a significant factor during 2 recent external validations. METHODS: The a-FRS was developed in 2 databases: the Dutch Pancreatic Cancer Audit (18 centers) and the University Hospital Southampton NHS. Primary outcome was grade B/C POPF according to the 2005 International Study Group on Pancreatic Surgery (ISGPS) definition. The score was externally validated in 2 independent databases (University Hospital of Verona and University Hospital of Pennsylvania), using both 2005 and 2016 ISGPS definitions. The a-FRS was also compared with the original-FRS. RESULTS: For model design, 1924 patients were included of whom 12% developed POPF. Three predictors were strongly associated with POPF: soft pancreatic texture [odds ratio (OR) 2.58, 95% confidence interval (95% CI) 1.80-3.69], small pancreatic duct diameter (per mm increase, OR: 0.68, 95% CI: 0.61-0.76), and high body mass index (BMI) (per kg/m increase, OR: 1.07, 95% CI: 1.04-1.11). Discrimination was adequate with an area under curve (AUC) of 0.75 (95% CI: 0.71-0.78) after internal validation, and 0.78 (0.74-0.82) after external validation. The predictive capacity of a-FRS was comparable with the original-FRS, both for the 2005 definition (AUC 0.78 vs 0.75, P = 0.03), and 2016 definition (AUC 0.72 vs 0.70, P = 0.05). CONCLUSION: The a-FRS predicts POPF after pancreatoduodenectomy based on 3 easily available variables (pancreatic texture, duct diameter, BMI) without blood loss and pathology, and was successfully validated for both the 2005 and 2016 POPF definition. The online calculator is available at www.pancreascalculator.com.