Defining the Minimal and Optimal Thresholds for Lymph Node Resection and Examination for Intraductal Papillary Mucinous Neoplasm Derived Pancreatic Cancer: A Multicenter Retrospective Analysis.

OBJECTIVE: To establish minimal and optimal lymphadenectomy thresholds for intraductal papillary mucinous neoplasm (IPMN)-derived pancreatic ductal adenocarcinoma (PDAC) and evaluate their prognostic value. BACKGROUND: Current guidelines recommend a minimum of 12-15 lymph nodes (LNs) in PDAC. This is largely based on pancreatic intraepithelial neoplasia (PanIN)-derived PDAC, a biologically distinct entity from IPMN-derived PDAC. METHODS: Multicenter retrospective study including consecutive patients undergoing upfront surgery for IPMN-derived PDAC was conducted. The minimum cut-off for lymphadenectomy was defined as the maximum number of LNs where a significant node positivity difference was observed. Maximally selected log-rank statistic was used to derive the optimal lymphadenectomy cut-off (maximize survival). Kaplan-Meier curves and log-rank tests were used to analyze overall survival (OS) and recurrence-free survival (RFS). Multivariable Cox-regression was used to determine hazard ratios (HR) with 95% confidence intervals (95%CI). RESULTS: In 341 patients with resected IPMN-derived PDAC, the minimum number of LNs needed to ensure accurate nodal staging was 10 (P=0.040), whereas ≥20 LNs was the optimal number associated with improved OS (80.3 vs. 37.2 mo, P<0.001). Optimal lymphadenectomy was associated with improved OS [HR:0.57 (95%CI 0.39-0.83)] and RFS [HR:0.70 (95%CI 0.51-0.97)] on multivariable Cox-regression. On sub-analysis the optimal lymphadenectomy cut-offs for pancreatoduodenectomy, distal pancreatectomy, and total pancreatectomy were 20 (P<0.001), 23 (P=0.160), and 25 (P=0.008). CONCLUSION: In IPMN-derived PDAC, lymphadenectomy with at least 10 lymph nodes mitigates under-staging, and at least 20 lymph nodes is associated with the improved survival. Specifically, for pancreatoduodenectomy and total pancreatectomy, 20 and 25 lymph nodes were the optimal cut-offs.

The impact of metastatic sites on survival Rates and predictors of extended survival in patients with metastatic pancreatic cancer.

BACKGROUND OBJECTIVES: The aim of this study was to determine the role of site-specific metastatic patterns over time and assess factors associated with extended survival in metastatic PDAC. Half of all patients with pancreatic ductal adenocarcinoma (PDAC) present with metastatic disease. The site of metastasis plays a crucial role in clinical decision making due to its prognostic value. METHODS: We examined 56,757 stage-IV PDAC patients from the National Cancer Database (2016-2019), categorizing them by metastatic site: multiple, liver, lung, brain, bone, carcinomatosis, or other. The site-specific prognostic value was assessed using log-rank tests while time-varying effects were assessed by Aalen's linear hazards model. Factors associated with extended survival (>3years) were assessed with logistic regression. RESULTS: Median overall survival (mOS) in patients with distant lymph node-only metastases (9.0 months) and lung-only metastases (8.1 months) was significantly longer than in patients with liver-only metastases (4.6 months, p < 0.001). However, after six months, the metastatic site lost prognostic value. Logistic regression identified extended survivors (3.6 %) as more likely to be younger, Hispanic, privately insured, Charlson-index <2, having received chemotherapy, or having undergone primary or distant site surgery (all p < 0.001). CONCLUSION: While synchronous liver metastases are associated with worse outcomes than lung-only and lymph node-only metastases, this predictive value is diminished after six months. Therefore, treatment decisions beyond this time should not primarily depend on the metastatic site. Extended survival is possible in a small subset of patients with favorable tumor biology and good conditional status, who are more likely to undergo aggressive therapies.

What is the optimal surgical approach for ductal adenocarcinoma of the pancreatic neck? - a retrospective cohort study.

BACKGROUND: The appropriate surgical approach for pancreatic ductal adenocarcinoma (PDAC) is determined by the tumor's relation to the porto-mesenteric axis. Although the extent and location of lymphadenectomy is dependent on the type of resection, a pancreatoduodenectomy (PD), distal pancreatectomy (DP), or total pancreatectomy (TP) are considered equivalent oncologic operations for pancreatic neck tumors. Therefore, we aimed to assess differences in histopathological and oncological outcomes for surgical approaches in the treatment of pancreatic neck tumors. METHODS: Patients with resected PDAC located in the pancreatic neck were identified from the National Cancer Database (2004-2020). Patients with metastatic disease were excluded. Furthermore, patients with 90-day mortality and R2-resections were excluded from the multivariable Cox-regression analysis. RESULTS: Among 846 patients, 58% underwent PD, 25% DP, and 17% TP with similar R0-resection rates (p = 0.722). Significant differences were observed in nodal positivity (PD:44%, DP:34%, TP:57%, p < 0.001) and mean-number of examined lymph nodes (PD:17.2 ± 10.4, DP:14.7 ± 10.5, TP:21.2 ± 11.0, p < 0.001). Furthermore, inadequate lymphadenectomy (< 12 nodes) was observed in 30%, 44%, and 19% of patients undergoing PD, DP, and TP, respectively (p < 0.001). Multivariable analysis yielded similar overall survival after DP (HR:0.83, 95%CI:0.63-1.11), while TP was associated with worse survival (HR:1.43, 95%CI:1.08-1.89) compared to PD. CONCLUSION: While R0-rates are similar amongst all approaches, DP is associated with inadequate lymphadenectomy which may result in understaging disease. However, this had no negative influence on survival. In the premise that an oncological resection of the pancreatic neck tumor is feasible with a partial pancreatectomy, no benefit is observed by performing a TP.

The Role of Intraoperative Pancreatoscopy in the Surgical Management of Intraductal Papillary Mucinous Neoplasms: A Scoping Review.

OBJECTIVES: Most patients with intraductal papillary mucinous neoplasms (IPMNs) are diagnosed with a solitary lesion; however, the presence of skip lesions, not appreciable on imaging, has been described. Postoperatively, these missed lesions can continue to grow and potentially become cancerous. Intraoperative pancreatoscopy (IOP) may facilitate detection of such skip lesions in the remnant gland. The aim of this scoping review was to appraise the evidence on the role of IOP in the surgical management of IPMNs. MATERIALS AND METHODS: Studies reporting on the use of IOP during IPMN surgery were identified through searches of the PubMed, Embase, and Scopus databases. Data extracted included IOP findings, surgical plan modifications, and patient outcomes. The primary outcome of interest was the utility of IOP in surgical decision making. RESULTS: Ten studies reporting on the use of IOP for IPMNs were identified, representing 147 patients. A total of 46 skip lesions were identified by IOP. Overall, surgical plans were altered in 37% of patients who underwent IOP. No IOP-related complications were reported. CONCLUSIONS: The current literature suggests a potential role of integration of IOP into the management of patients with IPMNs. This tool is safe and feasible and can result in changes in surgical decision making.

Bioabsorbable, subcutaneous naltrexone implants mitigate fentanyl-induced respiratory depression at 3 months-A pilot study in male canines.

The aim of this study is to determine if extended-release, bioabsorbable, subcutaneous naltrexone (NTX) implants can mitigate respiratory depression after an intravenous injection (IV) of fentanyl. Six different BIOabsorbable Polymeric Implant Naltrexone (BIOPIN) formulations, comprising combinations of Poly-d,l-Lactic Acid (PDLLA) and/or Polycaprolactone (PCL-1 or PCL-2), were used to create subcutaneous implants. Both placebo and naltrexone implants were implanted subcutaneously in male dogs. The active naltrexone implants consisted of two doses, 644 mg and 1288 mg. A challenge with IV fentanyl was performed in 33 male dogs at 97-100 days after implantation. Following the administration of a 30 µg/kg intravenous fentanyl dose, the placebo cohort manifested a swift and profound respiratory depression with a ~50% reduction in their pre-dose respiratory rate (RR). The BIOPIN NTX-implanted dogs were exposed to escalating doses of intravenous fentanyl (30 µg/kg, 60 µg/kg, 90 µg/kg, and 120 µg/kg). In contrast, the dogs implanted with the BIOPIN naltrexone implants tolerated doses up to 60 µg/kg without significant respiratory depression (<50%) but had severe respiratory depression with fentanyl doses of 90 µg/kg and especially at 120 µg/kg. Bioabsorbable, extended-release BIOPIN naltrexone implants are effective in mitigating fentanyl-induced respiratory depression in male canines at about 3 months after implantation. This technology may also have potential for mitigating fentanyl-induced respiratory depression in humans.