Most patients who have colorectal cancer peritoneal metastases (CRC-PM) treated with cytoreductive surgery ± hyperthermic intraperitoneal chemotherapy (CRS±HIPEC) experience recurrence within 1 year. This study assessed the safety and oncologic value of secondary CRS±HIPEC for patients with CRC-PM. A multi-institutional database of patients treated for CRC-PM (2000–2024) was reviewed. Patients who underwent curative-intent initial CRS±HIPEC alone were compared with those who underwent secondary CRS±HIPEC for recurrent disease. Patients who received more than two procedures were excluded. The primary objective was to evaluate the safety of secondary CRS±HIPEC for CRC-PM as measured by perioperative outcomes. The secondary objective was to examine the association between overall survival (OS) and secondary CRS±HIPEC. The study included 136 patients, 17 of whom underwent secondary CRS±HIPEC. There was no difference in postoperative complications between secondary and initial CRS±HIPEC. When OS was defined from the date of the index operation, secondary CRS±HIPEC was associated with improved OS versus initial CRS±HIPEC alone (51.0 months [95

BACKGROUND:Future liver remnant hypertrophy is the primary endpoint of portal vein embolization before major hepatectomy. However, even when adequate future liver remnant is achieved, postoperative hepatic insufficiency is not universally averted. We aimed to identify preoperative risk factors of postoperative hepatic insufficiency despite the use of portal vein embolization. METHODS:Patients who underwent portal vein embolization followed by major hepatectomy at 6 academic medical centers were retrospectively reviewed. Postoperative hepatic insufficiency was defined as postoperative peak bilirubin >7 mg/dL. Preoperative variables associated with postoperative hepatic insufficiency were analyzed. RESULTS:From 2008 to 2019, 164 patients underwent portal vein embolization followed by major hepatectomy. Twenty (12%) patients developed postoperative hepatic insufficiency. On univariate analysis, postoperative hepatic insufficiency was associated with older age, performance status, preoperative biliary drainage, smaller pre- and post-portal vein embolization future liver remnant volumes, diagnosis of cholangiocarcinoma/gallbladder cancer, and preoperative cholangitis. There was significant future liver remnant hypertrophy noted even in the setting of postoperative hepatic insufficiency (from 27% to 39%); however, degree of hypertrophy >5% (100% vs 93%, P = .6) and kinetic growth rate >2%/week (95% vs 82%, P = .3) did not differ between the postoperative hepatic insufficiency and non-postoperative hepatic insufficiency groups. On multivariate analysis, the diagnosis of cholangiocarcinoma/gallbladder cancer and preoperative cholangitis (postoperative hepatic insufficiency incidence 34% and 62%, respectively), but not future liver remnant volumetrics, were independently associated with postoperative hepatic insufficiency. Postoperative hepatic insufficiency raised post-hepatectomy 90-day mortality from 3.5% to 45% and hospitalization from 7 days to 16 days (both P < .001). CONCLUSION:Postoperative hepatic insufficiency still occurs in 12% of patients after major hepatectomy despite preoperative portal vein embolization. In addition to traditional volumetric information, surgeons should be aware of preoperative cholangitis and cholangiocarcinoma/gallbladder cancer as powerful predictors of this fatal complication.

Tumor heterogeneity is predicted to confer inferior clinical outcomes with precision-based strategies, however, modeling heterogeneity in a manner that still represents the tumor of origin remains a formidable challenge. Sequencing technologies are limited in their ability to identify rare subclonal populations and predict response to treatments for patients. Patient-derived organotypic cultures have significantly improved the modeling of cancer biology by faithfully representing the molecular features of primary malignant tissues. Patient-derived cancer organoid (PCO) cultures contain subclonal populations with the potential to recapitulate heterogeneity, although treatment response assessments commonly ignore diversity in the molecular profile or treatment response. Here, we demonstrate the advantage of evaluating individual PCO heterogeneity to enhance the sensitivity of these assays for predicting clinical response. Additionally, organoid subcultures identify subclonal populations with altered treatment response. Finally, dose escalation studies of PCOs to targeted anti-EGFR therapy are utilized which reveal divergent pathway expression when compared to pretreatment cultures. Overall, these studies demonstrate the importance of population-based organoid response assessments, the use of PCOs to identify molecular heterogeneity not observed with bulk tumor sequencing, and PCO heterogeneity for understanding therapeutic resistance mechanisms.

Background Pancreatic resection offers the only chance for cure for pancreatic ductal adenocarcinoma, but resection is associated with significant morbidity. Data are lacking about whether patients understand the risks/benefits of surgical resection. This survey study prospectively assessed patient understanding of expected oncologic outcomes after pancreatectomy. Methods A 14-question survey was distributed between 2020 and 2022 to patients planning to undergo pancreatectomy at eight geographically diverse institutions performing high-volume pancreatic surgery. The survey assessed demographics, expectations about post-resection outcomes, and perceived quality of patient-surgeon communication. Associations between demographics and survey responses were assessed with Fisher's exact test and Goodman-Kruskal's lambda. Results 152 surveys were received (response rate 39 %; n = 152/376). Almost all patients believed surgery was likely to prolong survival (146/147, 99 %); cure their cancer (126/141, 89 %); and/or ameliorate health problems due to cancer (127/136, 93 %). Regarding patient-surgeon communication, 134/150 (89 %) reported surgeons always listened carefully, and 134/150 (89 %) reported surgeons gave clear explanations. There were no meaningful associations between demographics and understanding of expected post-resection outcomes. Discussion Most patients believed surgery was likely curative and were satisfied with patient-surgeon communication. These data outline a critical opportunity for surgical oncologists to improve pre-operative counseling and ensure patients have accurate information to support complex decision-making.

Objective: This study evaluates outcomes for patients with unresectable colorectal liver metastases (CRLM) undergoing hepatic artery infusion chemotherapy (HAI) and transarterial radioembolization (TARE). Summary Background Data: The most common liver-directed therapies for unresectable CRLM include HAI and TARE. Methods: In this retrospective cohort study, patients with unresectable CRLM treated with HAI at one high-volume center were compared with patients treated with TARE at five other institutions. Propensity score matching was performed within lines of chemotherapy received prior to treatment (treatment-naïve; 1-line; 2-lines; 3-4 lines) using baseline demographics, extrahepatic disease (EHD), prior chemotherapy, disease-free interval, and interval from primary diagnosis to HAI/TARE. Overall survival (OS) analysis was conducted to compare the matched groups. Results: A total of 708 HAI patients and 481 TARE patients were identified. The majority of patients (84%) received chemotherapy prior to HAI/TARE. HAI patients were younger (median age:54 vs. 62) and more likely to have evidence of EHD at time of treatment (65% vs. 60%). Of the 493 patients who received 1-line of chemotherapy, 166 (34%) were matched. Among matched patients who received 1-line (HAI:83, TARE:83) or 2-lines of chemotherapy (HAI:80, TARE:80), TARE patients had a significantly increased risk of all-cause mortality compared to HAI [HR:1.46 (95%CI:1.02-2.08) and HR:1.96 (95%CI:1.32-2.89)]. More frequent conversion to resection and use of concurrent systemic chemotherapy were also seen in the HAI cohort. Among matched patients who received 3-4 lines of chemotherapy (HAI:50, TARE:50), there was no difference in OS between HAI and TARE [HR:0.88 (95%CI:0.57-1.35)] and rate of conversion to surgery was 4% for both groups. Conclusions: Within matched cohorts stratified by lines of therapy, there appear to be differences in survival for patients treated with HAI and TARE after first or second-line chemotherapy. Outcomes after TARE and HAI are not significantly different in the refractory setting.

BACKGROUND:Black patients with pancreatic ductal adenocarcinoma (PDAC) are less likely to have a major pathologic response (MPR) after neoadjuvant chemotherapy (NAC). Data suggest lower baseline carbohydrate antigen 19-9 (CA 19-9) among Black patients. Whether CA 19-9 nonproduction contributes to racial differences in NAC response was evaluated, and the biological mechanisms underlying the reduced response in CA 19-9 nonproducers (CAnonprod) were investigated. METHODS:Black and White patients with PDAC who received ≥2 NAC cycles and pancreatectomy at seven centers were reviewed. Patients were categorized as CA 19-9 producers (CAprod; CA 19-9 > 5 U/mL) or CAnonprod (CA 19-9 ≤ 5 U/mL). Univariable and multivariable models assessed CAnonprod rates by race and the association of CAnonprod with MPR. The Pancreatic Cancer Action Network's SPARK platform was queried for genomic data. Differentially mutated genes were identified by Fisher exact test; differentially expressed gene analysis used an absolute fold change of ≥2 and an adjusted p value of <.05. RESULTS:Among 415 patients (385 CAprod and 30 CAnonprod), Black patients comprised more CAnonprod than CAprod (50% vs. 13%; p < .01). MPR rates were lower among CAnonprod versus CAprod (8% vs. 26%; p = .03). CA nonproduction was associated with decreased odds of an MPR (odds ratio [OR], 0.21; 95% CI, 0.04-0.99), and Black race was associated with increased odds of CA 19-9 nonproduction (OR, 8.7; 95% CI, 3.8-19.7). CAnonprod had higher rates of SWI/SNF alterations than CAprod (52% vs. 34%; p < .01; p-adjusted, not significant). LIPF was downregulated and CTCFL was upregulated in CAnonprod. CONCLUSIONS:CA 19-9 nonproduction is more prevalent in Black patients, and potentially mediates lower rates of MPR. CAnonprod have a distinct molecular profile, which suggests a biological basis for racial differences in chemoresponsivity.

INTRODUCTION:Current decision support tools designed to predict postoperative complications, following cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC), are limited by small sample sizes and lack of external validation. Our aim was to develop an externally validated machine-learning tool that can predict severe complications (Clavien-Dindo grade ≥ 3) after CRS-HIPEC. METHODS:The dataset consisted of adult patients who underwent CRS-HIPEC at the University of Pittsburgh Medical Center (UPMC) and was split into an 80:20 ratio for the training and internal validation datasets, respectively. For external validation, we used the US HIPEC collaborative dataset. Three different models were trained and tested, and SHAP values were calculated to assess variable importance. RESULTS:A total of 37% (n = 719/1955) of cases in the UPMC cohort experienced severe postoperative complications compared to 22% (n = 134/617) in the US HIPEC collaborative dataset. Recursive feature elimination algorithm determined that the optimal performance was achieved with 15 variables. After optimization, the random forest model had the highest area under the ROC curve (AUC, 0.71) in the internal validation cohort and was chosen as the final model. The random forest model had an AUC that ranged from 0.60 to 0.73 (mean AUC, 0.65) in the external validation cohorts. Finally, the most important variables associated with severe complications were high PCI, subtotal gastrectomy, low albumin levels, small bowel resection, and high Charlson Comorbidity Index. CONCLUSIONS:Using the largest cohort of CRS-HIPEC patients in the US, we developed and externally validated a machine-learning model that can aid with patient selection and help providers anticipate complications in the postoperative setting.

609 Background: Black patients with pancreatic ductal adenocarcinoma (PDAC) are less likely to have major pathologic response (MPR) following induction chemotherapy compared to non-Black patients. Rare reports have suggested that Black patients are more likely to be CA 19-9 non-producers. We aimed to determine if disproportionate rates of CA 19-9 nonproduction underlie racial differences in neoadjuvant chemotherapy response in patients with localized PDAC. We also explored differences in somatic mutations between CA 19-9 producers (CAprod) and non-producers (CAnonprod). Methods: Black and White patients with localized PDAC receiving ≥ 2 cycles of neoadjuvant chemotherapy followed by pancreatectomy (2010-2019) at 7 high-volume centers were reviewed. Patients were categorized as CAprod (CA 19-9 > 5 U/mL) or CAnonprod (CA 19-9 ≤ 5 U/mL). Uni- and multi-variable models evaluated differences in rates of CAnonprod by race, and the association of CAnonprod with MPR (CAP 0/1). The Pancreatic Cancer Action Network (PanCAN)’s SPARK health data platform which contains clinical and multi-omic data from the PanCAN Know Your Tumor program was queried to identify patients with CA 19-9 and genomic data. Fisher’s exact test was used to compare differentially mutated genes between CAprod and CAnonprod patients. Results: Our cohort included 385 (93.3%) CAprod and 30 (6.7%) CAnonprod. CAnonprod patients were more likely to be Black than CAprod (50.0% vs 12.5%, p<0.01). There were no other differences in demographic or clinical features between CAnonprod and CAprod. Most patients received FOLFIRINOX vs Gemcitabine based chemotherapy (60.3% CAprod vs. 56.7% CAnonprod, p=0.27) with a median number of 4.0 vs 5.0 cycles (p=0.83), respectively. Rate of MPR was significantly higher in patients with CAprod compared with CAnonprod patients (26.3% vs 7.7%, p=0.03). No CAnonprod patient had a complete pathologic response vs 28 (7.3%) of CAprod (p=0.12). CAnonprod was independently associated with decreased odds of MPR (OR 0.21, CI [0.04-0.99]). Black race was independently associated with increased odds of CAnonprod (OR 8.66, CI [3.81 – 19.7]). When stratified by production of CA 19-9, there was no significant difference between rate of MPR between Black and White patients. In the PanCAN KYT analysis, CAnonproduc had higher rates of SWI/SNF alterations (50.0% of CAnonprod vs 30.1% of CAprod, P<0.01;P-adj=ns; ARID1B was the most frequently mutated SWI/SNF gene in CAnonprod (31.0% vs 9.0% CApos, p<0.01; P-adj=ns). Conclusions: CAnonprod were more likely to be Black and have significantly worse rates of MPR following neoadjuvant chemotherapy in patients with localized PDAC. Moreover, CAnonprod was associated with higher rates of SWI/SNF alterations, noting a potential biologic basis for racial differences in chemotherapy response to curative-intent treatment for PDAC.

652 Background: Radiation may have a role in management of patients with early-stage pancreatic cancer. However, the role of regional nodal irradiation (RNI) is not well defined despite the high frequency of occult nodal disease. The goal of this trial was to evaluate the safety and feasibility of stereotactic body radiation therapy (SBRT) to primary disease with RNI, combined with capecitabine as a neoadjuvant approach for patients with resectable pancreatic cancer. Updated survival analysis will be presented here. Methods: This is a prospective, single institution, phase IA/B dose-escalation trial that enrolled patients with biopsy-proven, resectable, pancreatic adenocarcinoma between 2014 – 2019 (NCT1918644). Patients were enrolled into one of the 3 cohorts with escalating dose levels. Neoadjuvant SBRT to the primary tumor was delivered in 5 fractions of 5, 6, or 7 Gy with concomitant capecitabine. All patients received RNI 5 Gy x 5 fractions. Our initial report found no dose-limiting toxicities (Witt et al IJROBP 2020). Clinicopathologic features were summarized using descriptive statistics. Kaplan-Meier curves were employed for survival analysis. Results: Seventeen patients were enrolled on the protocol with sixteen evaluable (94.1%). Thirteen (76.5%) patients proceeded to surgery. Median follow up was 31.1 months (2.0 – 73.2). Among the evaluable patients, 63% were male, median age at diagnosis was 73 years (63 – 84), pre-treatment CA 19-9 149.5 U/mL (2.0 – 19358.0). The majority of patients had cT2-3 (94%) and cN0 (87.5%) disease. In patients who underwent resection, median time from radiation to surgery was 19.7 days (14.8 – 42.4), with median of 18 lymph nodes removed (11 – 27). Pathologically involved nodes were present in 69.2% of patients with a median of 2 nodes (1 – 10). Five patients (31.3%) received neoadjuvant chemotherapy, and ten (62.5%) received adjuvant chemotherapy. At the time of data cutoff, median overall survival was 31.1 months (2.3 – 73.6), and median locoregional control and distant metastasis free survivals were 32.8 months (4.0 – 59.5) and 15.3 months (0.4 – 73.6), respectively. No further radiation related toxicities were noted since the prior report. Conclusions: Neoadjuvant chemoradiation with SBRT and capecitabine to primary disease with RNI is feasible and provided a promising signal of durable local control in our study, despite high rates of pathological nodal involvement. Further investigation of this strategy is warranted in a larger cohort of patients. Clinical trial information: NCT1918644 .

In this initial report of a prospective, single-institution clinical trial of hypofractionated RT for STS not undergoing resection, we report low rates of acute grade 3 or greater toxicity and high rates of tumor response. We will continue to follow these patients to assess late toxicity and durability of tumor control.

Background In patients with localized pancreatic ductal adenocarcinoma (PDAC) undergoing neoadjuvant therapy (NAT) and resection, selection of adjuvant chemotherapy (AC) is typically guided by high-risk features on histopathologic examination. We evaluated the interaction between post-NAT lymph node metrics and AC receipt on survival. Methods Patients who received NAT followed by pancreatectomy (2010-2020) at seven centers were reviewed. Overall survival (OS) in patients receiving AC or not was stratified by lymph node positivity (LNP) or lymph node ratio (LNR) dichotomized at 0.1. Cox models evaluated the independent association between these nodal metrics, AC receipt, and OS. Results Of 464 patients undergoing NAT and resection, 264 (57%) received AC. Patients selected for AC were younger (median 63 vs. 67 years; p < 0.001), received shorter duration of NAT (2.8 vs. 3.2 months; p = 0.01), had fewer postoperative complications (Clavien-Dindo grade > 3: 1.2% vs. 11.7%; p < 0.001), and lower rates of pathologic complete response (4% vs. 11%; p = 0.01). The median number of nodes evaluated was similar between cohorts (n = 20 in both; p = 0.9). Post-NAT LNP rates were not different, and median LNR was 0.1, in AC and non-AC cohorts. Both LNP (hazard ratio [HR]: 2.1, p < 0.001) and LNR (0 < LNR <= 0.1: HR: 1.98, p = 0.002; LNR > 0.1: HR 2.46, p < 0.001) were independently associated with OS on Cox modeling, although receipt of AC was not associated with improved OS (median 30.6 vs. 29.4 months; p = 0.2). In patients with LNR > 0.1, receipt of AC was associated with significantly longer OS compared to non-AC (24 vs. 20 months, respectively; p = 0.04). Conclusions LNR following NAT, not simply nodal positivity, may be useful to refine selection of AC in resected PDAC.

Gallbladder carcinoma (GBC) is the most common biliary epithelial malignancy, with an estimated incidence of 1.13 cases per 100,000 in the United States (Hundal and Shaffer in Clin Epidemiol 6:99-109, 2014 1; Henley et al. in Cancer Epidemiol Biomarkers Prev 24:1319-1326, 2015 2). The insidious nature and late presentation of this disease place it among the most lethal invasive neoplasms. Gallbladder cancer spreads early by lymphatic or hematogenous metastasis, as well as by direct invasion into the liver. While surgery may be curative at early stages, both surgical and nonsurgical treatments remain largely unsuccessful in patients with more advanced diseases (Rahman et al. in Cancer Med 6:874-880, 2017 3).

Gallbladder carcinoma (GBC) is the most common biliary epithelial malignancy, with an estimated incidence of 1.13 cases per 100,000 in the United States (Hundal and Shaffer in Clin Epidemiol 6:99-109, 2014 1; Henley et al. in Cancer Epidemiol Biomarkers Prev 24:1319-1326, 2015 2). The insidious nature and late presentation of this disease place it among the most lethal invasive neoplasms. Gallbladder cancer spreads early by lymphatic or hematogenous metastasis, as well as by direct invasion into the liver. While surgery may be curative at early stages, both surgical and nonsurgical treatments remain largely unsuccessful in patients with more advanced diseases (Rahman et al. in Cancer Med 6:874-880, 2017 3).

Abstract Introduction: Black patients with pancreatic ductal adenocarcinoma (PDAC) are less likely to have major pathologic response (MPR) following induction chemotherapy. Our previous study suggested a lower baseline CA 19-9 among Black patients. We aimed to determine if CA 19-9 nonproduction contributes to racial differences in neoadjuvant chemotherapy (NAC) response. We then investigated the biological mechanisms underlying reduced response in CAnonprod with multi-omic analysis. Methods: Black and White patients with PDAC receiving ≥ 2 cycles of NAC followed by pancreatectomy at 7 high-volume centers were reviewed. Patients were categorized as CAproducers (CAprod, CA 19-9 > 5 U/mL) or CAnonprod (CA 19-9 ≤ 5 U/mL). Uni- and multi-variable models evaluated differences in rates of CAnonprod by race, and the association of CAnonprod with MPR (CAP 0/1). The Pancreatic Cancer Action Network SPARK platform was queried for patients with CA 19-9 and genomic data. Fisher’s exact test was used to compare differentially mutated genes between CAnonprod and CAprod. Differential gene expression (DEG) analysis identified significantly differentially expressed genes using an absolute fold change of ≥ 2 and p-adj < 0.05 as a cutoff. quanTIseq computational pipeline was used for immune cell deconvolution analysis of the two groups. Results: Our cohort included 385 CAprod and 30 CAnonprod. CAnonprod had a significantly higher rate of Black patients (50% vs 13%, p<0.01). Compared with CAprod, CAnonprod received similar rates of FOLFIRINOX (60% vs. 57%, p=0.27) and duration of NAC (4 vs 5 cycles, p=0.83). Rate of MPR was higher among CAprod compared to CAnonprod (26% vs 8%, p=0.03). No CAnonprod patient had a complete pathologic response vs 28 (7%) of CAprod (p=0.12). CAnonprod was independently associated with decreased odds of MPR (OR 0.21, CI [0.04-0.99]). Black race was independently associated with increased odds of CAnonprod (OR 8.66, CI [3.81 – 19.7]). When CA 19-9 production status was matched by race, there was no difference between rate of MPR between White and Black CAnonprod; both experienced low rates of MPR (12% and 9%, respectively, (p=0.68)). CAnonprod had higher rates of SWI/SNF alterations (50% CAnonprod vs 33% CAprod, p< 0.01; P-adj=ns), and ARID1B was the most frequently mutated gene in CAnonprod (28% vs 11%, p< 0.01; P-adj=ns). DEG analysis showed the LIPF gene was significantly downregulated in CAnonprod compared to CAprod. There was no difference in immune cell distribution between CAprod and CAnonprod. Conclusion: CA 19-9 non-production is more prevalent in Black patients and potentially mediates the lower rates of MPR following NAC. CA 19-9 non-production is associated with higher rates of SWI/SNF alterations and a downregulation of the LIPF gene encoding gastric lipase, unveiling a potential biologic or metabolomic difference in response to chemotherapy between races. Citation Format: Mary P. Martos, Erin M. Dickey, Kawther Abdilleh, Syed A. Ahmad, Shishir K. Maithel, Chet W. Hammill, Hong Jin Kim, Daniel E. Abbott, David A. Kooby, Alexander A. Parikh, Peter J. Hosein, Nipun B. Merchant, Jashodeep Datta, Caitlin A. Hester. Black race and CA 19-9 nonproduction is associated with limited pathologic response to neoadjuvant chemotherapy in patients with localized pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A019.

INTRODUCTION:Patients with colorectal peritoneal metastases (CRPM) are increasingly treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). Unfortunately, data identifying preoperative risk factors for poor oncologic outcomes after this procedure are limited. We aimed to determine the prognostic value of preoperative CEA, CA 125, and CA 19-9 on disease progression after CRS/HIPEC.METHODS:Patients with CRPM treated with curative intent CRS/HIPEC from 12 participating sites in the United States from 2000 to 2017 were identified. Progression-free survival (PFS), defined as disease progression or recurrence, was the primary outcome.RESULTS:In 279 patients who met inclusion criteria, the rate of disease progression was 63.8%, with a median PFS of 11 months (interquartile range [IQR] 5-20). Elevated CA 19-9 was associated with dismal PFS at 2 years (8.9% elevated vs. 30% not elevated, p < 0.01). In 113 patients who underwent upfront CRS/HIPEC, CA 19-9 emerged as the sole tumor marker independently predictive of worse PFS (hazard ratio [HR] 2.88, p = 0.048). In the subgroup of patients who had received neoadjuvant therapy (NAT), no variable was independently predictive of PFS. CA 19-9 levels over 37 U/ml were highly specific for accelerated disease progression after CRS/HIPEC. Lastly, there was no association between PFS and elevated CEA or CA 125.CONCLUSIONS:Elevated CA 19-9 is associated with decreased PFS in patients with CRPM. While traditionally CEA is the main tumor marker assessed in colon cancer, we found that CA 19-9 may better inform preoperative risk stratification for poor oncologic outcomes in patients with CRPM. However, prospective studies are required to confirm this association.

Introduction We explored the association between weekend discharge and 30- and 90-d readmission rates in patients undergoing hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) for peritoneal carcinomatosis. Methods The US HIPEC Collaborative database, comprised of a longitudinal cohort of patients undergoing CRS/HIPEC for peritoneal carcinomatosis at twelve academic institutions between 2000 and 2017, was queried for date of discharge information. Patients were retrospectively divided into weekday and weekend/holiday discharge groups. Patients <18 y old, lacking day of discharge information, or who experienced intraoperative/in-hospital mortality were excluded. Comparisons were made between patients discharged on a weekday versus those discharged on a weekend or major holiday. Results 1415 patients met inclusion criteria for the study: 1108 (78%) patients with a weekday discharge and 308 (22%) with a weekend/holiday discharge. Median age at time of surgery was 55 y (Interquartile Range: 46-63); 59% (n = 841) patients were female, 25% (n = 328) of patients had high volume disease (defined as a peritoneal cancer index >20 intraoperatively), and 92% (n = 1210) of patients had a complete cytoreduction (defined as a completeness of cytoreduction score of 0 or 1). Overall, 15% (n = 218) of patients were readmitted within 30 d and 19% (n = 265) within 90 d. In a linear mixed effects model, weekend discharge was not associated with higher 30- or 90-d readmissions (P = 0.291, P = 0.743). Conclusions Weekend discharges are safe following CRS/HIPEC. Length of stay initiatives should focus on discharging the patient when medically ready, rather than avoiding weekend discharge out of an abundance of caution.

Background and Objectives: Pancreaticoduodenectomy (PD), the only surgical option for right-sided pancreatic ductal adenocarcinoma (PDAC), carries significant morbidity. Not all patients may be deriving a survival benefit from this operation. We sought to identify the rate of futile PD and its associated factors in a large national cohort. Methods: We performed a retrospective analysis using the National Cancer Database (2004-2020), including all patients who underwent PD for non-metastatic PDAC. The primary outcome was operative futility, which was defined as death within 12 months of diagnosis despite PD. Multivariable regression was used to identify factors associated with futility. We performed a subgroup analysis on patients who received neoadjuvant systemic therapy. Results: Data from 66 326 patients were analyzed, and 16 772 (25.3%) underwent PD that met criteria for futility. Macroscopically positive margins (odds ratio [OR]: 2.87; 95% confidence interval [CI]: 2.36-3.48), poor tumor differentiation (OR: 2.44; 95% CI: 2.25-2.65), and N2 nodal stage (OR: 2.09; 95% CI: 1.98-2.20) were associated with the greatest odds of futility. Meanwhile, receipt of any systemic therapy (OR: 0.33; 95% CI: 0.31-0.34), receipt of any radiation (OR: 0.60; 95% CI: 0.57-0.63), and receipt of neoadjuvant systemic therapy (OR: 0.62; 95% CI: 0.57-0.66) were associated with the lowest odds of futility. In the neoadjuvant subgroup, a longer diagnosis-to-surgery interval was associated with lower odds of futility. Conclusion: PD was futile in about one quarter of patients. Futility was associated with higher age and worse tumor biology. Receipt of neoadjuvant therapy resulted in fewer futile operations.