Improved survival of patients receiving immunotherapy and chemotherapy following curative-intent resection of colorectal liver metastases.

BACKGROUND: Despite significant advancements in the treatment of patients with colorectal liver metastases (CRLMs), only a minority will experience long-term survival. This study aimed to determine the effect of chemotherapy (CT) and immunotherapy (IT) compared with that of CT alone on patient survival after surgical resection. METHODS: Patients undergoing curative-intent liver resection followed by adjuvant systemic therapy for stage IV colon cancer were identified using the National Cancer Database. Patients were stratified into type of therapy (CT alone vs CT + IT) and microsatellite status. Propensity score-weighted analysis was performed through 1:1 matching based on the nearest neighbor method. RESULTS: Of 9943 patients who underwent resection of CRLMs, 7971 (80%) received systemic adjuvant therapy. Of 7971 patients, 1432 (18%) received a combination of CT and IT. Microsatellite status was not associated with overall survival (OS). Adjuvant CT + IT was associated with increased 3-year OS compared with that of CT alone in both the unmatched cohort (55% vs 48%, respectively; P < .001) and matched cohort (52% vs 48%, respectively; P = .050). On multivariate analysis, older age, positive resection margins, and KRAS mutation were independent predictors of poor survival, whereas the administration of adjuvant CT + IT was an independent predictor of improved survival. CONCLUSION: IT combined with CT was associated with improved survival compared with that of CT alone after curative-intent resection of CRLMs, regardless of microsatellite instability status. Clinical trials to determine optimal patient selection, IT regimen, and long-term efficacy to improve outcomes of patients with CRLMs are warranted.

Metastatic melanoma to small bowel: metastasectomy is supported in the era of immunotherapy and checkpoint inhibitors.

BACKGROUND: Metastatic melanoma to the small bowel is an aggressive disease often accompanied by obstruction, abdominal pain, and gastrointestinal bleeding. With advancements in melanoma treatment, the role for metastasectomy continues to evolve. Inclusion of novel immunotherapeutic agents, such as checkpoint inhibitors, into standard treatment regimens presents potential survival benefits for patients receiving metastasectomy. CASE PRESENTATION: We report an institutional experience of 15 patients (12 male, 3 female) between 2014-2022 that underwent small bowel metastasectomy for metastatic melanoma and received perioperative systemic treatment. Median age of patients was 64 years (range: 35-83 years). No patients died within 30 days of their surgery, and the median hospital length of stay was 5 days. Median overall survival in these patients was 30.1 months (range: 2-115 months). Five patients died from disease (67 days, 252 days, 426 days, 572 days, 692 days postoperatively), one patient died of non-disease related causes (1312 days postoperatively), six patients are alive with disease, and three remain disease free. CONCLUSIONS: This case series presents an updated perspective of the utility of metastasectomy for small bowel metastasis in the age of novel immunotherapeutic agents as standard systemic treatment. Small bowel metastasectomy for advanced melanoma performed in conjunction with perioperative systemic therapy is safe and appears to promote long-term survival and enhanced quality of life.

RIM-BP2 regulates Ca2+ channel abundance and neurotransmitter release at hippocampal mossy fiber terminals.

Synaptic vesicles dock and fuse at the presynaptic active zone (AZ), the specialized site for transmitter release. AZ proteins play multiple roles such as recruitment of Ca2+ channels as well as synaptic vesicle docking, priming, and fusion. However, the precise role of each AZ protein type remains unknown. In order to dissect the role of RIM-BP2 at mammalian cortical synapses having low release probability, we applied direct electrophysiological recording and super-resolution imaging to hippocampal mossy fiber terminals of RIM-BP2 knockout (KO) mice. By using direct presynaptic recording, we found the reduced Ca2+ currents. The measurements of excitatory postsynaptic currents (EPSCs) and presynaptic capacitance suggested that the initial release probability was lowered because of the reduced Ca2+ influx and impaired fusion competence in RIM-BP2 KO. Nevertheless, larger Ca2+ influx restored release partially. Consistent with presynaptic recording, STED microscopy suggested less abundance of P/Q-type Ca2+ channels at AZs deficient in RIM-BP2. Our results suggest that the RIM-BP2 regulates both Ca2+ channel abundance and transmitter release at mossy fiber synapses.

A Machine Learning Approach to Predict Postoperative Pancreatic Fistula After Pancreaticoduodenectomy Using Only Preoperatively Known Data.

BACKGROUND: Clinically-relevant postoperative pancreatic fistula (CR-POPF) following pancreaticoduodenectomy (PD) is a major postoperative complication and the primary determinant of surgical outcomes. However, the majority of current risk calculators utilize intraoperative and postoperative variables, limiting their utility in the preoperative setting. Therefore, we aimed to develop a user-friendly risk calculator to predict CR-POPF following PD using state-of-the-art machine learning (ML) algorithms and only preoperatively known variables. METHODS: Adult patients undergoing elective PD for non-metastatic pancreatic cancer were identified from the ACS-NSQIP targeted pancreatectomy dataset (2014-2019). The primary endpoint was development of CR-POPF (grade B or C). Secondary endpoints included discharge to facility, 30-day mortality, and a composite of overall and significant complications. Four models (logistic regression, neural network, random forest, and XGBoost) were trained, validated and a user-friendly risk calculator was then developed. RESULTS: Of the 8666 patients who underwent elective PD, 13% (n = 1160) developed CR-POPF. XGBoost was the best performing model (AUC = 0.72), and the top five preoperative variables associated with CR-POPF were non-adenocarcinoma histology, lack of neoadjuvant chemotherapy, pancreatic duct size less than 3 mm, higher BMI, and higher preoperative serum creatinine. Model performance for 30-day mortality, discharge to a facility, and overall and significant complications ranged from AUC 0.62-0.78. CONCLUSIONS: In this study, we developed and validated an ML model using only preoperatively known variables to predict CR-POPF following PD. The risk calculator can be used in the preoperative setting to inform clinical decision-making and patient counseling.

National Practice Patterns in Malignant Peritoneal Mesothelioma: Updates in Management and Survival.

BACKGROUND: Malignant peritoneal mesothelioma (MPM) is a rare malignancy with a historically poor prognosis. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has emerged as an effective therapy for patients with peritoneal malignancies. A contemporary analysis of trends in management of and survival from MPM is warranted. METHODS: Patients with MPM were identified from the National Cancer Database (2004-2018). Patients were categorized by treatment (CRS-HIPEC, CRS-chemotherapy, CRS only, chemotherapy only, no treatment), and joinpoint regression was employed to compute the annual percent change (APC) in treatment over time. Multivariable Cox proportional hazards models were used to analyze factors associated with survival. RESULTS: Of 2683 patients with MPM, 19.1% underwent CRS-HIPEC, and 21.1% received no treatment. Joinpoint regression revealed a statistically significant increase in the proportion of patients undergoing CRS-HIPEC over time (APC 3.21, p = 0.01), and a concurrent decrease in the proportion of patients who underwent no treatment (APC - 2.21, p = 0.02). Median overall survival was 19.5 months. Factors independently associated with survival included CRS-HIPEC, CRS, histology, sex, age, race, Charlson Comorbidity Index, insurance, and hospital type. Although there was a strong association between year of diagnosis and survival on univariate analysis (2016-2018 HR 0.67, p < 0.001), this association was attenuated after adjustment for treatment. CONCLUSIONS: CRS-HIPEC is increasingly employed as a treatment for MPM. In parallel, there has been a decrease in patients receiving no treatment with an increase in overall survival. These findings suggest that patients with MPM may be receiving more appropriate therapy; however, a substantial proportion of patients may remain undertreated.

Compartmentalization of soluble endocytic proteins in synaptic vesicle clusters by phase separation.

Synaptic vesicle (SV) clusters, which reportedly result from synapsin's capacity to undergo liquid-liquid phase separation (LLPS), constitute the structural basis for neurotransmission. Although these clusters contain various endocytic accessory proteins, how endocytic proteins accumulate in SV clusters remains unknown. Here, we report that endophilin A1 (EndoA1), the endocytic scaffold protein, undergoes LLPS under physiologically relevant concentrations at presynaptic terminals. On heterologous expression, EndoA1 facilitates the formation of synapsin condensates and accumulates in SV-like vesicle clusters via synapsin. Moreover, EndoA1 condensates recruit endocytic proteins such as dynamin 1, amphiphysin, and intersectin 1, none of which are recruited in vesicle clusters by synapsin. In cultured neurons, like synapsin, EndoA1 is compartmentalized in SV clusters through LLPS, exhibiting activity-dependent dispersion/reassembly cycles. Thus, beyond its essential function in SV endocytosis, EndoA1 serves an additional structural function by undergoing LLPS, thereby accumulating various endocytic proteins in dynamic SV clusters in concert with synapsin.

Metastatic colorectal adenocarcinoma tumor purity assessment from whole exome sequencing data.

Tumors rich in stroma are associated with advanced stage and poor prognosis in colorectal adenocarcinoma (CRC). Abundance of stromal cells also has implications for genomic analysis of patient tumors as it may prevent detection of somatic mutations. As part of our efforts to interrogate stroma-cancer cell interactions and to identify actionable therapeutic targets in metastatic CRC, we aimed to determine the proportion of stroma embedded in hepatic CRC metastases by performing computational tumor purity analysis based on whole exome sequencing data (WES). Unlike previous studies focusing on histopathologically prescreened samples, we used an unbiased in-house collection of tumor specimens. WES from CRC liver metastasis samples were utilized to evaluate stromal content and to assess the performance of three in silico tumor purity tools, ABSOLUTE, Sequenza and PureCN. Matching tumor derived organoids were analyzed as a high purity control as they are enriched in cancer cells. Computational purity estimates were compared to those from a histopathological assessment conducted by a board-certified pathologist. According to all computational methods, metastatic specimens had a median tumor purity of 30% whereas the organoids were enriched for cancer cells with a median purity estimate of 94%. In line with this, variant allele frequencies (VAFs) of oncogenes and tumor suppressor genes were undetectable or low in most patient tumors, but higher in matching organoid cultures. Positive correlation was observed between VAFs and in silico tumor purity estimates. Sequenza and PureCN produced concordant results whereas ABSOLUTE yielded lower purity estimates for all samples. Our data shows that unbiased sample selection combined with molecular, computational, and histopathological tumor purity assessment is critical to determine the level of stroma embedded in metastatic colorectal adenocarcinoma.

Increased vesicle fusion competence underlies long-term potentiation at hippocampal mossy fiber synapses.

Presynaptic long-term potentiation (LTP) is thought to play an important role in learning and memory. However, the underlying mechanism remains elusive because of the difficulty of direct recording during LTP. Hippocampal mossy fiber synapses exhibit pronounced LTP of transmitter release after tetanic stimulation and have been used as a model of presynaptic LTP. Here, we induced LTP by optogenetic tools and applied direct presynaptic patch-clamp recordings. The action potential waveform and evoked presynaptic Ca2+ currents remained unchanged after LTP induction. Membrane capacitance measurements suggested higher release probability of synaptic vesicles without changing the number of release-ready vesicles after LTP induction. Synaptic vesicle replenishment was also enhanced. Furthermore, stimulated emission depletion microscopy suggested an increase in the numbers of Munc13-1 and RIM1 molecules within active zones. We propose that dynamic changes in the active zone components may be relevant for the increased fusion competence and synaptic vesicle replenishment during LTP.

Hypertension Requiring Medication Use: a Silent Predictor of Poor Outcomes After Pancreaticoduodenectomy.

BACKGROUND: Although hypertension requiring medication (HTNm) is a well-known cardiovascular comorbidity, its association with postoperative outcomes is understudied. This study aimed to evaluate whether preoperative HTNm is independently associated with specific complications after pancreaticoduodenectomy. STUDY DESIGN: Adults undergoing elective pancreaticoduodenectomy were included from the 2014-2019 NSQIP-targeted pancreatectomy dataset. Multivariable regression models compared outcomes between patients with and without HTNm. Endpoints included significant complications, any complication, unplanned readmissions, length of stay (LOS), clinically relevant postoperative pancreatic fistula (CR-POPF), and cardiovascular and renal complications. A subgroup analysis excluded patients with diabetes, heart failure, chronic obstructive pulmonary disease, estimated glomerular filtration rate from serum creatinine (eGFRCr) < 60 ml/min per 1.73 m2, bleeding disorder, or steroid use. RESULTS: Among 14,806 patients, 52% had HTNm. HTNm was more common among older male patients with obesity, diabetes, congestive heart failure, chronic obstructive pulmonary disease, functional dependency, hard pancreatic glands, and cancer. After adjusting for demographics, preoperative comorbidities, and laboratory values, HTNm was independently associated with higher odds of significant complications (aOR 1.12, p = 0.020), any complication (aOR 1.11, p = 0.030), cardiovascular (aOR 1.78, p = 0.002) and renal (aOR 1.60, p = 0.020) complications, and unplanned readmissions (aOR 1.14, p = 0.040). In a subgroup analysis of patients without major preoperative comorbidity, HTNm remained associated with higher odds of significant complications (aOR 1.14, p = 0.030) and cardiovascular complications (aOR 1.76, p = 0.033). CONCLUSIONS: HTNm is independently associated with cardiovascular and renal complications after pancreaticoduodenectomy and may need to be considered in preoperative risk stratification. Future studies are necessary to explore associations among underlying hypertension, specific antihypertensive medications, and postoperative outcomes to investigate potential risk mitigation strategies.

Hand-Assisted Versus Pure Minimally-Invasive Distal Pancreatectomy: Is There a Downside to Lending a Hand?

BACKGROUND: Hand-assisted laparoscopic distal pancreatectomy (HALDP) is suggested to offer similar outcomes to pure laparoscopic distal pancreatectomy (LDP). However, given the longer midline incision, it is unclear whether HALDP increases the risk of postoperative hernia. Our aim was to determine the risk of postoperative incisional hernia development after HALDP. METHODS: We retrospectively collected data from patients undergoing HALDP or LDP at a single center (2012-2020). Primary endpoints were postoperative incisional hernia and operative time. All patients had at minimum six months of follow-up. Outcomes were compared using unadjusted and multivariable regression analyses. RESULTS: Ninety-five patients who underwent laparoscopic distal pancreatectomy were retrospectively identified. Forty-one patients (43%) underwent HALDP. Patients with HALDP were older (median, 67 vs. 61 years, p = 0.02). Sex, race, Body Mass Index (median, 27 vs. 26), receipt of neoadjuvant chemotherapy, gland texture, wound infection rates, postoperative pancreatic fistula, overall complications, and hospital length-of-stay were similar between HALDP and LDP (all p > 0.05). In unadjusted analysis, operative times were shorter for HALDP (164 vs. 276 min, p < 0.001), but after adjustment, did not differ significantly (MR 0.73; 0.49-1.07, p = 0.1). Unadjusted incidence of hernia was higher in HALDP versus LDP (60% vs. 24%, p = 0.004). After adjustment, HALDP was associated with an increased odds of developing hernia (OR 7.52; 95% CI 1.54-36.8, p = 0.014). After propensity score matching, odds of hernia development remained higher for HALDP (OR 4.62; 95% CI 1.28-16.65, p = 0.031) p = 0.03). CONCLUSIONS: Compared with LDP, HALDP was associated with increased likelihood of postoperative hernia with insufficient evidence that HALDP shortens operative times. Our results suggest that HALDP may not be equivalent to LDP.

Minimally Invasive Distal Pancreatectomy Techniques: A Contemporary Analysis Exploring Trends, Similarities, and Differences to Open Surgery.

Limited contemporary data has compared similarities and differences between total laparoscopic (LDP), hand-assisted (HALDP), and open distal pancreatectomy (ODP). This study aimed to examine similarities and differences in outcomes between these three approaches in a contemporary cohort. Methods: Patients undergoing elective LDP, HALDP, and ODP in the NSQIP dataset (2014−2019) were included. Descriptive statistics and multivariate regression analyses were employed to compare postoperative outcomes. Results: Among 5636 patients, 33.9% underwent LDP, 13.1% HALDP, and 52.9% ODP. Compared with the LDP approach, surgical site infections were more frequent in HALDP and ODP approaches (1.2% vs. 2.6% vs. 2.8%, respectively, p < 0.01). After adjustment, the LDP approach was associated with a significantly lower likelihood of surgical site infection (OR 0.25, p = 0.03) when compared to ODP. There was no difference in the likelihood of surgical site infection when HALDP was compared to ODP (OR 0.59, p = 0.40). Unadjusted operative times were similar between approaches (LDP = 192 min, HALDP = 193 min, ODP = 191 min, p = 0.59). After adjustment, the LDP approach had a longer operative time (+10.3 min, p = 0.04) compared to ODP. There was no difference in the adjusted operative time between HALDP and ODP approaches (+5.4 min, p = 0.80). Conclusions: Compared to ODP, LDP was associated with improved surgical site infection rates and slightly longer operative times. There was no difference in surgical site infection rates between ODP and HALDP. Surgeon comfort and experience should decide the operative approach, but it is important to discuss the differences between these approaches with patients.

Using Electronic Health Record Meta-Data to Identify Variation in Trainee Progress Note Writing Patterns: Opportunity to Enhance Systems-Based Care.

OBJECTIVE: Daily progress notes are the backbone of all inpatient hospitalizations. Progress notes serve as a lasting record of a patient's diagnoses, condition, and planned interventions and are essential communication tools. We designed a study to identify patterns in progress note filing and use on general surgical services. METHODS: The electronic health record (EHR) data warehouse was queried for general surgical progress notes signed between July 1, 2020, and July 1, 2021. Only notes authored by resident physicians or advanced practice providers (APPs) were included, and those filed on the day of a surgery were excluded. 10 am was identified as a target for note completion as it coincided with multidisciplinary discharge rounds. Physician, case managers pharmacist, physical therapist, dietician, nurse (and collaborating disciplines) progress note views were measured using EHR access log data. RESULTS: A total of 8384 progress notes were analyzed; 4146 notes (49%) were authored by 81 trainees. A total of 4433 (53%) progress notes were filed before 10 am, 3673 (44%) were filed between 10 am and 6 pm, and 278 (3%) were filed after 6 pm. Variation in progress note file time was observed and associated with individual habits, residents vs APPs, day-of-week, and service structure. Surgery progress notes are viewed by collaborating disciplines throughout the workday, with high-volume viewership occurring by mid-morning. Each individual progress note received an average of 17.6 lifetime views with a range of 1 to 76. An average of 10.2 of those views occurred on the same day that the note was written. Notes that were filed after 10 am received a significantly lower number of same-day views compared to notes filed before 10am (8.4 vs 11.8, p < 0.0001). CONCLUSIONS: Progress notes are identified as a significant burden by trainees and even considered to contribute to duty hour violations, yet they are used regularly as a source of information for collaborating disciplines. Progress notes filed earlier are viewed more frequently. Efforts to identify barriers to timeliness may help communication and efficiency of inpatient surgical care.

Emotional Regulation in Surgery: Fostering Well-Being, Performance, and Leadership.

Emotional regulation is increasingly gaining acceptance as a means to improve well-being, performance, and leadership across high-stakes professions, representing innovation in thinking within the field of surgical education. As one part of a broader cognitive skill set that can be trained and honed, emotional regulation has a strong evidence base in high-stress, high-performance fields. Nevertheless, even as Program Directors and surgical educators have become increasingly aware of this data, with emerging evidence in the surgical education literature supporting efficacy, hurdles to sustainable implementation exist. In this white paper, we present evidence supporting the value of emotional regulation training in surgery and share case studies in order to illustrate practical steps for the development, adaptation, and implementation of emotional regulation curricula in three key developmental contexts: basic cognitive skills training, technical skills acquisition and performance, and preparation for independence. We focus on the practical aspects of each case to elucidate the challenges and opportunities of introducing and adopting a curricular innovation into surgical education. We propose an integrated curriculum consisting of all three applied contexts for emotional regulation skills and advocate for the dissemination of such a longitudinal curriculum on a national level.

Contemporary Trends in Malignant Peritoneal Mesothelioma: Incidence and Survival in the United States.

Background: Malignant peritoneal mesothelioma (MPM) is a rare disease with a historically poor prognosis. Given the emergence of effective therapies, a contemporary analysis of MPM incidence and survival is warranted. Methods: The SEER-18 registry dataset was analyzed (2000−2018). Age-adjusted annual incidence was stratified by sex and histology. Joinpoint regression was used to estimate annual percent change (APC) in incidence. Multivariable cox proportional hazards models were used to investigate survival trends. Results: Of 1689 MPM cases, most were male (55.4%), >50 years (80.0%), and white (75.2%). Age-adjusted incidence of MPM remained stable over time, with an average annual incidence of 1.02 cases/million. Epithelioid histology increased by 240% (APC 2.6; 95% CI: 0.7, 4.5), while incidence of undefined histology decreased significantly (APC −2.1; 95% CI: −3.1, −1.1). Cases treated with cancer-directed surgery increased from 27% to 43%. Overall median age-standardized survival was 11.6 months. Median age-standardized survival was 16.6 months for epithelioid histology but 2.0 months for sarcomatoid histology. Diagnosis in recent years (2015−2018 HR 0.51; 95% CI: 0.38, 0.67) and receipt of cancer-directed surgery (HR 0.84; 95% CI: 0.72, 0.98) were associated with improved survival. Conclusions: Although the overall incidence of MPM remained stable, recognition of epithelioid histology increased. Concurrent with an increase in cancer-directed surgery, MPM survival has improved.

Determining Hospital Volume Threshold for Safety of Minimally Invasive Pancreaticoduodenectomy: A Contemporary Cutpoint Analysis.

BACKGROUND: Guidelines recommend limiting minimally invasive pancreaticoduodenectomy (MIPD) to high-volume centers. However, the definition of high-volume care remains unclear. We aimed to objectively define a minimum number of MIPD performed annually per hospital associated with improved outcomes in a contemporary patient cohort. PATIENTS AND METHODS: Resectable pancreatic adenocarcinoma patients undergoing MIPD were included from the National Cancer Database (2010-2017). Multivariable modeling with restricted cubic splines was employed to identify an MIPD annual hospital volume threshold associated with lower 90-day mortality. Outcomes were compared between patients treated at low-volume (≤ model-identified cutoff) and high-volume (> cutoff) centers. RESULTS: Among 3079 patients, 141 (5%) died within 90 days. Median hospital volume was 6 (range 1-73) cases/year. After adjustment, increasing hospital volume was associated with decreasing 90-day mortality for up to 19 (95% CI 16-25) cases/year, indicating a threshold of 20 cases/year. Most cases (82%) were done at low-volume (< 20 cases/year) centers. With adjustment, MIPD at low-volume centers was associated with increased 90-day mortality (OR 2.7; p = 0.002). Length of stay, positive surgical margins, 30-day readmission, and overall survival were similar. On analysis of the most recent two years (n = 1031), patients at low-volume centers (78.2%) were younger and had less advanced tumors but had longer length of stay (8 versus 7 days; p < 0.001) and increased 90-day mortality (7% versus 2%; p = 0.009). CONCLUSIONS: The cutpoint analysis identified a threshold of at least 20 MIPD cases/year associated with lower postoperative mortality. This threshold should inform national guidelines and institution-level protocols aimed at facilitating the safe implementation of this complex procedure.

Discovery of an F-actin-binding small molecule serving as a fluorescent probe and a scaffold for functional probes.

Actin is a ubiquitous cytoskeletal protein, forming a dynamic network that generates mechanical forces in the cell. There is a growing demand for practical and accessible tools for dissecting the role of the actin cytoskeleton in cellular function, and the discovery of a new actin-binding small molecule is an important advance in the field, offering the opportunity to design and synthesize of new class of functional molecules. Here, we found an F-actin­binding small molecule and introduced two powerful tools based on a new class of actin-binding small molecule: One enables visualization of the actin cytoskeleton, including super-resolution imaging, and the other enables highly specific green light­controlled fragmentation of actin filaments, affording unprecedented control of the actin cytoskeleton and its force network in living cells.

Quantitative modeling of regular retinal microglia distribution.

Microglia are resident immune cells in the central nervous system, showing a regular distribution. Advancing microscopy and image processing techniques have contributed to elucidating microglia's morphology, dynamics, and distribution. However, the mechanism underlying the regular distribution of microglia remains to be elucidated. First, we quantitatively confirmed the regularity of the distribution pattern of microglial soma in the retina. Second, we formulated a mathematical model that includes factors that may influence regular distribution. Next, we experimentally quantified the model parameters (cell movement, process formation, and ATP dynamics). The resulting model simulation from the measured parameters showed that direct cell-cell contact is most important in generating regular cell spacing. Finally, we tried to specify the molecular pathway responsible for the repulsion between neighboring microglia.