Number of evaluated lymph nodes and positive lymph nodes, lymph node ratio, and log odds evaluation in early-stage pancreatic ductal adenocarcinoma: numerology or valid indicators of patient outcome?

Radiogenomic analysis for predicting lymph node metastasis and molecular annotation of radiomic features in pancreatic cancer

BACKGROUND

To provide a preoperative prediction model for lymph node metastasis in pancreatic cancer patients and provide molecular information of key radiomic features.

METHODS

Two cohorts comprising 151 and 54 pancreatic cancer patients were included in the analysis. Radiomic features from the tumor region of interests were extracted by using PyRadiomics software. We used a framework that incorporated 10 machine learning algorithms and generated 77 combinations to construct radiomics-based models for lymph node metastasis prediction. Weighted gene coexpression network analysis (WGCNA) was subsequently performed to determine the relationships between gene expression levels and radiomic features. Molecular pathways enrichment analysis was performed to uncover the underlying molecular features.

RESULTS

Patients in the in-house cohort (mean age, 61.3 years ± 9.6 [SD]; 91 men [60%]) were separated into training (n = 105, 70%) and validation (n = 46, 30%) cohorts. A total of 1,239 features were extracted and subjected to machine learning algorithms. The 77 radiomic models showed moderate performance for predicting lymph node metastasis, and the combination of the StepGBM and Enet algorithms had the best performance in the training (AUC = 0.84, 95% CI = 0.77-0.91) and validation (AUC = 0.85, 95% CI = 0.73-0.98) cohorts. We determined that 15 features were core variables for lymph node metastasis. Proliferation-related processes may respond to the main molecular alterations underlying these features.

CONCLUSIONS

Machine learning-based radiomics could predict the status of lymph node metastasis in pancreatic cancer, which is associated with proliferation-related alterations.

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

OBJECTIVE

To assess the frequency of occult metastases (OM) in patients with resected pancreatic ductal adenocarcinoma (PDAC) or ampullary adenocarcinoma (AA) discovered on detailed pathologic examination on lymph nodes (LNs) previously considered negative by conventional analysis and to examine the association between OM and overall survival (OS).

BACKGROUND

Poor prognosis of patients with no pathologic evidence of LN metastases may be due to OM that is not detected on conventional LN analysis.

METHODS

Patients with LN-negative resected PDAC or AA (2010-2020) were identified from our institutional database. Original hematoxylin and eosin ( H and E ) slides were reanalyzed. In addition, selected LN were analyzed by H and E (3 sections/LN) and pan-cytokeratin (AE1-AE3/PCK26) immunohistochemistry.

RESULTS

A total of 598 LNs from 74 LN-negative patients were reexamined. Nineteen patients (25.7%) had OM; 9 (47.4%) were found with immunohistochemistry but not on H and E . The number of positive LNs ranged from 1 to 3. No clinicodemographic, pathologic, or treatment-related factors were associated with OM. On conventional LN analysis, 3/19 patients (15.8%) had stage IA, 9/34 (26.5%) had stage IB, and 7/19 (36.8%) had stage IIA. On detailed LN analysis, 11/19 patients (57.9%) were upstaged to IIB, whereas 8/19 (42.1%) had isolated tumor cells only (N0i+). OM was associated with shorter OS (median OS: 22.3 vs 50.5 months; hazard ratio=3.95, 95% CI: 1.58-9.86).

CONCLUSIONS

There is a 26% discordance rate between conventional and detailed LN pathologic analysis in resected PDAC and AA. The presence of OM is associated with shorter OS.

CT-measured body composition radiomics predict lymph node metastasis in localized pancreatic ductal adenocarcinoma

BACKGROUND

To explored the value of CT-measured body composition radiomics in preoperative evaluation of lymph node metastasis (LNM) in localized pancreatic ductal adenocarcinoma (LPDAC).

METHODS

We retrospectively collected patients with LPDAC who underwent surgical resection from January 2016 to June 2022. According to whether there was LNM after operation, the patients were divided into LNM group and non-LNM group in both male and female patients. The patient's body composition was measured by CT images at the level of the L3 vertebral body before surgery, and the radiomics features of adipose tissue and muscle were extracted. Multivariate logistic regression (forward LR) analyses were used to determine the predictors of LNM from male and female patient, respectively. Sexual dimorphism prediction signature using adipose tissue radiomics features, muscle tissue radiomics features and combined signature of both were developed and compared. The model performance is evaluated on discrimination and validated through a leave-one-out cross-validation method.

RESULTS

A total of 196 patients (mean age, 60 years ± 9 [SD]; 117 men) were enrolled, including 59 LNM in male and 36 LNM in female. Both male and female CT-measured body composition radiomics signatures have a certain predictive power on LNM of LPDAC. Among them, the female adipose tissue signature showed the highest performance (area under the ROC curve (AUC), 0.895), and leave one out cross validation (LOOCV) indicated that the signature could accurately classify 83.5% of cases; The prediction efficiency of the signature can be further improved after adding the muscle radiomics features (AUC, 0.924, and the accuracy of the LOOCV was 87.3%); The abilities of male adipose tissue and muscle tissue radiomics signatures in predicting LNM of LPDAC was similar, AUC was 0.735 and 0.773, respectively, and the accuracy of LOOCV was 62.4% and 68.4%, respectively.

CONCLUSIONS

CT-measured body composition Radiomics strategy showed good performance for predicting LNM in LPDAC, and has sexual dimorphism. It may provide a reference for individual treatment of LPDAC and related research about body composition in the future.

Artificial Intelligence to Predict Lymph Node Metastasis at CT in Pancreatic Ductal Adenocarcinoma

Background Although deep learning has brought revolutionary changes in health care, reliance on manually selected cross-sectional images and segmentation remain methodological barriers. Purpose To develop and validate an automated preoperative artificial intelligence (AI) algorithm for tumor and lymph node (LN) segmentation with CT imaging for prediction of LN metastasis in patients with pancreatic ductal adenocarcinoma (PDAC). Materials and Methods In this retrospective study, patients with surgically resected, pathologically confirmed PDAC underwent multidetector CT from January 2015 to April 2020. Three models were developed, including an AI model, a clinical model, and a radiomics model. CT-determined LN metastasis was diagnosed by radiologists. Multivariable logistic regression analysis was conducted to develop the clinical and radiomics models. The performance of the models was determined on the basis of their discrimination and clinical utility. Kaplan-Meier curves, the log-rank test, or Cox regression were used for survival analysis. Results Overall, 734 patients (mean age, 62 years ± 9 [SD]; 453 men) were evaluated. All patients were split into training (n = 545) and validation (n = 189) sets. Patients who had LN metastasis (LN-positive group) accounted for 340 of 734 (46%) patients. In the training set, the AI model showed the highest performance (area under the receiver operating characteristic curve [AUC], 0.91) in the prediction of LN metastasis, whereas the radiologists and the clinical and radiomics models had AUCs of 0.58, 0.76, and 0.71, respectively. In the validation set, the AI model showed the highest performance (AUC, 0.92) in the prediction of LN metastasis, whereas the radiologists and the clinical and radiomics models had AUCs of 0.65, 0.77, and 0.68, respectively (P < .001). AI model-predicted positive LN metastasis was associated with worse survival (hazard ratio, 1.46; 95% CI: 1.13, 1.89; P = .004). Conclusion An artificial intelligence model outperformed radiologists and clinical and radiomics models for prediction of lymph node metastasis at CT in patients with pancreatic ductal adenocarcinoma. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Chu and Fishman in this issue.

Pancreatic head cancer - Current surgery techniques

Pancreatic head cancer is a highly fatal disease. For now, surgery offers the only potential long-term cure albeit with a high risk of complications. However, the progress of surgical technique during the past decade has resulted in 5-year survival approaching 30% after resection and adjuvant chemotherapy. This paper presents current data on the recommended extent of lymphadenectomy, the resection margin, on the definition of resectable and borderline resectable tumors and mesopancreas. Surgical techniques proposed to improve PD are presented: the artery first approach, the uncinate process first, the mesopancreas first approach, the triangle operation, periarterial divestment, and multiorgan resection.

Evaluation of the 8th Edition AJCC Staging System for the Clinical Staging of Pancreatic Cancer

The 8th edition of the American Joint Committee on Cancer (AJCC) staging system for pancreatic cancer (PC) has been validated for pathological staging; however, its significance for clinical staging remains uncertain. We validated the prognostic performance and suitability of the current staging system for the clinical staging of PC. We identified 1043 patients from our PC registry who were staged by imaging according to the 8th edition staging system and conducted analysis, including overall survival (OS) comparison. Gradual prognostic stratification according to stage hierarchy yielded significant OS differences between stage groups, except between stage I and II (p = 0.193). A substage comparison revealed no survival differences between IB (T2N0) and IIA (T3N0), which were divided by the T3 criterion only (p = 0.278). A higher N stage had significantly shorter OS than a lower N stage (all pairwise p < 0.05). However, among the 150 patients who received upfront surgery, the pathological stage was more advanced than the clinical stage in 86 (57.3%), mostly due to a false-negative cN0 (70.9%). Our results suggest that the new definition of T3 and the number-based N criteria in the 8th edition AJCC staging system may be not adequate for clinical staging. Establishing separate criteria more suitable for clinical staging should be considered.

Predictive Performance of Current Nodal Staging Systems in Various Categories of Pancreatic Cancer

BACKGROUND

Nodal staging systems (NSS) for pancreatic ductal adenocarcinoma (PDAC) classify patients on the basis of number of metastatic lymph nodes (MLN), metastatic/retrieved lymph node ratio (LNR), and log odds of positive LN (LODDS). The relative prognostic performance of these NSS, however, remains unclear.

PATIENTS AND METHODS

We identified 2584 patients who underwent surgery for PDAC between 2010 and 2019. Subgroups of each staging system were classified using K-adaptive partitioning method and assessed by comparing time-dependent areas under the curve (AUC) 5 years after surgery.

RESULTS

Patients were subgrouped by MLN (0, 1-3, ≥ 4), LNR (0, 0-0.23, > 0.23), and LODDS (< - 3.5, - 3.5 to - 0.970, > - 0.97). All three NSS were independent prognostic factors for overall survival (OS) and recurrence-free survival (RFS). The AUCs for OS were comparable for the MLN (0.622), LNR (0.609), and LODDS (0.596) systems. Subgroup evaluation based on 12 retrieved lymph nodes (RLN), R1 resection, and extent of resection showed that the AUCs of the MLN and LNR NSS were comparable for OS and RFS regardless of the number of RLNs, R1 resection, and extent of resection. By contrast, the AUCs of the LODDS NSS were lower.

CONCLUSION

The NSS based on the number of MLN is the best prognostic indicator, with prognostic performance comparable to the other NSS and greater convenience for practical use. This NSS was applicable regardless of the numbers of RLN, R1 resection, and extent of resection.

A Novel Criterion for Lymph Nodes Dissection in Distal Pancreatectomy for Ductal Adenocarcinoma: A Population Study of the US SEER Database

OBJECTIVE

The aim of this study was to clarify the minimum number of examined lymph nodes (MNELNs) required to ensure the quality of lymph node detection and its impact on long-term survival in distal pancreatectomy for pancreatic ductal adenocarcinoma.

METHODS

Clinicopathological characteristics and survival data of patients with resectable pancreatic cancer who underwent distal pancreatectomy between 2004 and 2017 were collected from the Surveillance, Epidemiology, and End Results database. The associations between the number of examined lymph nodes (ELNs) and number of positive lymph nodes (PLNs), stage migration, and overall survival were investigated through adjusted multivariate models with locally weighted scatterplot smoothing smoothing fitting curves and estimation of the structural breakpoints. Kaplan-Meier survival analysis and X-tile software were used to identify the ideal cut-off value for ELNs.

RESULTS

In total, 2610 consecutive patients who underwent distal pancreatectomy between 2004 and 2017 were included in this study. The optimal ELN count according to the associations between the number of ELNs and number of PLNs, odds ratio for stage migration, or hazard ratio for overall survival were 19, 17, and 19, respectively. Furthermore, the optimal division of ELN count for maximum overall survival was divided into three populations (ELN ≤ 8, ELN 9-18, ELN ≥ 19) based on X-tile software.

CONCLUSION

A minimal count of 19 lymph nodes was demanded to guarantee the quality of lymph node examination in patients with distal pancreatectomy. Long-term survival could be delimited by MNELNs. A sufficient number of ELNs could improve the accuracy of cancer staging and reflect a better overall survival.

Does direct invasion of peripancreatic lymph nodes impact survival in patients with pancreatic ductal adenocarcinoma? A retrospective dual-center study

BACKGROUND

Pancreatic ductal adenocarcinoma can directly invade the peripancreatic lymph nodes; however, the significance of direct lymph node invasion is controversial, and it is currently classified as lymph node metastasis. This study aimed to identify the impact of direct invasion of peripancreatic lymph nodes on survival in patients with pancreatic ductal adenocarcinoma.

METHODS

A total of 411 patients with resectable/borderline resectable pancreatic ductal adenocarcinoma who underwent pancreatic resection at two high-volume centers from 2006 to 2016 were evaluated retrospectively.

RESULTS

Sixty (14.6%) patients had direct invasion of the peripancreatic lymph nodes without isolated lymph node metastasis (N-direct group), 189 (46.0%) had isolated lymph node metastasis (N-met group), and 162 (39.4%) had neither direct invasion nor isolated metastasis (N0 group). There was no significant difference in median overall survival between the N-direct group (35.0 months) and the N0 group (45.6 month) (p = 0.409), but survival was significantly longer in the N-direct compared with the N-met group (25.0 months) (p = 0.003). Similarly, median disease-free survival was similar in the N-direct (21.0 months) and N0 groups (22.7 months) (p = 0.151), but was significantly longer in the N-direct compared with the N-met group (14.0 months) (p < 0.001). Multivariate analysis identified resectability, adjuvant chemotherapy, and isolated lymph node metastasis as independent predictors of overall survival. However, direct lymph node invasion was not a predictor of survival.

CONCLUSION

Direct invasion of the peripancreatic lymph nodes had no effect on survival in patients undergoing pancreatic resection for pancreatic ductal adenocarcinoma, and should therefore not be classified as lymph node metastasis.

Original study: The rescue staging for pancreatic ductal adenocarcinoma with inadequate examined lymph nodes

BACKGROUND

In previous studies, it's recommended that the lymph node involvement should be evaluated with enough examined lymph nodes (eLNs) in the 8th American Joint Committee on Cancer (AJCC) staging system for pancreatic cancer. This study aims to put forward a rescue staging system for pancreatic ductal adenocarcinoma (PDAC) patients with inadequate eLNs after pancreatoduodenectomy (PD).

METHOD

11,224 PDAC patients undergoing PD in The Surveillance, Epidemiology, and End Results (SEER) database were included. Another Ruijin Pancreatic Disease Center (RJPDC) database consisted of 821 patients was utilized for external validation.

RESULTS

The proportions of patients with eLNs≥15 were 44.7% and 32.8% in SEER and RJPDC database separately. The rescue staging system was put forward relying on LNR (HR = 1.83, 95% CI 1.74-1.92, P < 0.001) for N staging of eLNs<15 population and pLNs for the rest. The TNM modalities were also rearranged in the rescue system for better survival coordination. The C-index of rescue staging system was 0.638 while that of AJCC 8th staging system was 0.613 in SEER database. Similar phenomena were observed in RJPDC database. Kaplan-Meier analyses revealed reliable internal coherences (SEER: Ib: P = 0.26; IIa: P = 0.063; IIb: P = 0.53; IIIa: P = 0.11.

RJPDC

Ib: P = 0.32; IIa: P = 0.66; IIb: P = 0.76; IIIa: P = 0.66) and significant staging efficiency (SEER: P < 0.001; RJPDC: P = 0.002).

CONCLUSION

A rescue staging system was put forward regardless of the eLNs number. And the novel system manifested better predictive capacity than 8th AJCC staging system.

Complete resection of the gastric antrum decreased incidence and severity of delayed gastric emptying after pancreaticoduodenectomy

BACKGROUND

Delayed gastric emptying (DGE) is the main complication after pancreaticoduodenectomy (PD), but the mechanism is still unclear. The aim of this study was to elucidate the role of complete resection of the gastric antrum in decreasing incidence and severity of DGE after PD.

METHODS

Sprague-Dawley rats were divided into three groups: expanded resection (ER group), complete resection (CR group), and incomplete resection (IR group) of the gastric antrum. The tension (g) of remnant stomach contraction was observed. We analyzed the histological morphology of the gastric wall by different excisional methods after distal gastrectomy. Moreover, patients underwent PD at our department between January 2012 and May 2016 were included in the study. These cases were divided into IR group and CR group of the gastric antrum, and the clinical data were retrospectively analyzed.

RESULTS

The ex vivo remnant stomachs of CR group exhibited much greater contraction tension than others (P < 0.05). The contraction tension of the remnant stomach increased with increasing acetylcholine concentration, while remained stable at the concentration of 10 × 10-5 mol/L. Furthermore, 174 consecutive patients were included and retrospectively analyzed in the study. The incidence of DGE was significantly lower (3.5% vs. 21.3%, P < 0.01) in CR group than in IR group. In addition, hematoxylin-eosin staining analyses of the gastric wall confirmed that the number of transected circular smooth muscle bundles were higher in IR group than in CR group (8.24 ± 0.65 vs. 3.76 ± 0.70, P < 0.05).

CONCLUSIONS

The complete resection of the gastric antrum is associated with decreased incidence and severity of DGE after PD. Gastric electrophysiological and physiopathological disorders caused by damage to gastric smooth muscles might be the mechanism underlying DGE.

Peritumoral lymph nodes in pancreatic cancer revisited; is it truly equivalent to lymph node metastasis?

BACKGROUND

Lymph node (LN) metastasis is a well-known poor prognostic factor of pancreatic cancer. LN metastasis, through direct invasion of tumor cell to peritumoral lymph nodes (PTLN), is treated as the same as those which spread through lymphatic channels. This study aimed to evaluate the impact of PTLN invasion on the oncologic outcome of pancreatic cancer.

METHODS

Five hundred and six patients who underwent operation for pancreatic ductal adenocarcinoma from 2012 to 2018 were reviewed. PTLN invasion was defined as direct invasion of tumor cells in contact with main tumor.

RESULTS

Among the 506 patients, 112 patients (22.1%) had PTLN invasion. PTLN invasion group (PTLNI) showed better disease-free survival than regional LN metastasis group (RLNM) and combined LN metastasis group (CLNM) (PTLNI 21 vs RLNM 11 vs CLNM 12 months, P = .003). There was no significant difference between N0 and PTLNI (PTLNI 21 vs N0 23 months, P = .999). In multivariate analysis, conventional LN metastasis was a significant factor compared to N0, but PTLN invasion was not (hazard ratio 0.786 [0.507-1.220], P = .283).

CONCLUSION

Because PTLN invasion does not adversely affect survival in the same way as LN metastasis does, pancreatic cancer-may be overstaged if PTLN invasion were dealt in the same manner as a metastatic LN. Therefore, PTLN invasion should be disregarded from current nodal staging system.

Comparison of different lymph node staging systems in patients with positive lymph nodes in oral squamous cell carcinoma

OBJECTIVES

The evaluation of neck lymph node metastasis is critical for predicting survival after head and neck cancer treatment. However, traditional pathological N staging does not completely correlate with survival; the total number of lymph nodes resected during surgery affects staging, and a minimal number of nodes must be resected to achieve a superior outcome. Thus, the prognostic abilities of various lymph node staging systems for oral cavity squamous cell carcinoma (OSCC)-positive lymph nodes were compared.

MATERIALS AND METHODS

Data for 639 patients with OSCC-positive nodes who were treated and monitored at the Changhua Christian Hospital were retrospectively analyzed. The different N staging systems were compared to evaluate their disease-free survival (DFS) predictability.

RESULTS

The areas under the receiver operating characteristic curve were as follows: 0.551 for the traditional American Joint Committee on Cancer (AJCC) N staging, 0.60 for lymph node density (LND), 0.596 for log odds of positive lymph nodes (LODDS), and 0.597 for the number of metastatic lymph nodes (nmLN). The LND, LODDS, and nmLN systems could predict DFS better than AJCC N staging. Multivariable analysis for DFS revealed that extranodal spread, level IV or V positive nodes, and tumor invasion deeper than 13 mm were independent prognostic factors in these four models. LND and LODDS predicted DFS better than pathological N staging.

CONCLUSION

LND and LODDS staging predicted DFS better than AJCC N staging for OSCC-positive nodes. In the future, the prognostic ability of AJCC staging may be strengthened by LND or LODDS staging.

Prognostic Role of Examined and Positive Lymph Nodes after Distal Pancreatectomy for Non-Functioning Neuroendocrine Neoplasms

BACKGROUND

The most appropriate nodal staging system for non-functioning pancreatic neuroendocrine tumours (NF-PanNETs) remains unclear. Despite some evidence is available for pancreaticoduodenectomy, the adequate nodal staging is still unknown for distal pancreatectomy (DP). The aim of the present study was to evaluate the prognostic impact of the number of positive lymph nodes (PLNs) after DP for NF-PanNETs and to define the minimal number of lymph nodes to be harvested for an appropriate nodal staging.

METHODS

Data were retrospectively collected from patients who underwent DP with curative intent (R0-R1) for sporadic well-differentiated NF-PanNETs in 4 European high-volume centres. NF-PanNETs with nodal involvement (N+) were subclassified into N1 (1-3 PLNs) and N2 (4 or more PLNs). Univariate and multivariate analyses of disease-free survival (DFS) were performed.

RESULTS

Of 271 patients in the study, 62 (23%) had nodal involvement (N+). A higher probability of N+ was associated with the following factors: grading, resection margin status, perineural and microvascular invasion, and the number of examined lymph nodes. Three-year DFS rate for N0, N1, and N2 patients was 92, 72, and 50%, respectively (p < 0.001). At multivariate analysis, independent predictors of DFS were grading, T stage, presence of necrosis, and nodal status. For patients with ≥12 examined/resected lymph nodes, the N status remained a significant predictor of disease recurrence (p < 0.001), while it failed to predict recurrence in patients with <12 lymph nodes examined/resected (p = 0.116).

CONCLUSIONS

A minimal number of 12 nodes should be harvested in case of DP for NF-PanNET for an appropriate nodal staging. The number of positive lymph nodes is an independent predictor of DFS after DP for NF-PanNET, and the N0/N1/N2 nodal classification seems to be more relevant than the current N0/N+ staging.

Comparison of Minimally Invasive Versus Open Pancreatoduodenectomy for Pancreatic Ductal Adenocarcinoma: A Propensity Score Matching Analysis

Background: Few studies have compared perioperative and oncological outcomes between minimally invasive pancreatoduodenectomy (MIPD) and open pancreatoduodenectomy (OPD) for pancreatic ductal adenocarcinoma (PDAC). Methods: A retrospective review of patients undergoing MIPD and OPD for PDAC from January 2011 to December 2017 was performed. Perioperative, oncological, and survival outcomes were analyzed before and after propensity score matching (PSM). Results: Data from 1048 patients were evaluated (76 MIPD, 972 OPD). After PSM, 73 patients undergoing MIPD were matched with 219 patients undergoing OPD. Operation times were longer for MIPD than OPD (392 vs. 327 min, p < 0.001). Postoperative hospital stays were shorter for MIPD patients than OPD patients (12.4 vs. 14.2 days, p = 0.040). The rate of overall complications and postoperative pancreatic fistula did not differ between the two groups. Adjuvant treatment rates were higher following MIPD (80.8% vs. 59.8%, p = 0.002). With the exception of perineural invasion, no differences were seen between the two groups in pathological outcomes. The median overall survival and disease-free survival rates did not differ between the groups. Conclusions: MIPD showed shorter postoperative hospital stays and comparable perioperative and oncological outcomes to OPD for selected PDAC patients. Future randomized studies will be required to validate these findings.

Prognostic impact of lymph node status in patients after total pancreatectomy for pancreatic ductal adenocarcinoma: A strobe-compliant study

The optimal number of examined lymph nodes (ELN) for staging and impact of nodal status on survival following total pancreatectomy (TP) for pancreatic ductal adenocarcinoma (PDAC) is unclear. The aim of this study was to evaluate the prognostic impact of different lymph node status after TP for PDAC.The Surveillance, Epidemiology, and End Results (SEER) database was used to identify patients who underwent TP for PDAC from 2004 to 2015. We calculated overall survival (OS) of these patients using Kaplan-Meier analysis and Cox proportional hazards model.Overall, 1291 patients were included in the study, with 869 node-positive patients (49.5%). A cut-off points analysis revealed that 19, 19, and 13 lymph nodes best discriminated OS for all patients, node-negative patients, and node-positive patients, respectively. Higher number of ELN than the corresponding cut-off points was an independent predictor for better prognosis [all patients: hazard ratios (HR) 0.786, P = .002; node-negative patients: HR 0.714, P = .043; node-positive patients: HR 0.678, P < .001]. For node-positive patients, 1 to 3 positive lymph nodes (PLN) correlated independently with better survival compared with those with 4 or more PLN (HR 1.433, P = .002). Moreover, when analyzed in node-positive patients with less than 13 ELN, neither the number of PLN nor lymph node ratio (LNR) was associated with survival. However, when limited node-positive patients with at least 13 ELN, univariate analyses showed that both the number of PLN and LNR were associated with survival, whereas multivariate analyses demonstrated that only number of PLN was consistently associated with survival (HR 1.556, P = .004).Evaluation at least 19 lymph nodes should be considered as quality metric of surgery in patients who underwent TP for PDAC. For node-negative patients, a minimal number of 19 lymph nodes is adequate to avoid stage migration. For node-positive patients, PLN is superior to LNR in predicting survival after TP, predominantly for those with high number of ELN.

The Role of Log Odds of Positive Lymph Nodes in Predicting the Survival after Resection for Ampullary Adenocarcinoma

Lymph node metastasis is a important factor on survival in ampullary adenocarcinoma. Log odds of positive lymph nodes (LODDS) is a novel prognostic indicator on lymph node status. We aimed to evaluate the prognostic impact of LODDS for the patients with ampullary adenocarcinoma who underwent R0 pancreaticoduodenectomy. The study includes 42 patients.. LODDS was calculated as "log (number of metastatic lymph nodes+0.5)/(number of total harvested nodes - metastatic lymph nodes+0.5)". LODDS subgroups were created based on their LODDS value: LODDS1(LODDS≤ - 1.5), LODDS2(-1.5 < LODDS≤ - 1.0), LODDS3(-1.0 < LODDS≤ - 0.5), LODDS4(LODDS> - 0.5). The mean survival time was 72.7 ± 7.82 months. Survival rates for 1, 3 and 5 years were 93%, 65% and 45%, respectively. The mean LODDS value was -1.0466 ± 0.51. LODDS subgroups show strong correlation with Overall Survival(OS). The mean survival were 114.8, 81.8, 56.6 and 25.6 months in LODDS subgroups 1, 2, 3 and 4, respectively (Log-rank; p = 0.002), in addition LOODS values shows correlation with perineural invasion and micro vascular invasion (p = 0.015 and p = 0.001 respectively). Findings in our patient group support the hypothesis that LODDS subgroups correlate with OS, and that value of LODDS has considerable role in prediction of OS as well.

Lymph node ratio as valuable predictor in pancreatic cancer treated with R0 resection and adjuvant treatment

Background

Lymph-node (LN) metastasis is an important prognostic factor in resected pancreatic cancer. In this study, the prognostic value of American Joint Committee on Cancer (AJCC) 8th edition N stage, lymph-node ratio (LNR), and log odds of positive lymph nodes (LODDS) in resected pancreatic cancer was investigated.

Methods

Between January 2005 and December 2017, there were 351 patients with pancreatic cancer treated with R0 resection and adjuvant therapy at Seoul National University Hospital. Relationships between the three LN parameters and overall survival (OS) and recurrence-free survival (RFS) were evaluated using a log-rank test and Cox proportional hazard regression model. Each multivariate-adjusted LN parameter was internally validated by bootstrap-corrected Harrell’s C-index.

Results

The mean duration from surgery to adjuvant therapy was 47.6 ± 17.4 days. In total, the median OS and RFS was 31.7 (95% CI, 27.2-37.2) and 15.4 (95% CI, 13.5-17.7) months. The three LN classification systems were significantly correlated with OS and RFS in log-rank tests and multivariate-adjusted models (all p < 0.05). When internally validated, LNR showed the highest discrimination ability in predicting OS and RFS (each C–index = 0.65). LNR also showed the highest C-index in subgroup analysis, classified by adjuvant therapy modality. LNR and the AJCC 8th edition LN classification system were significantly associated with loco-regional recurrence (p = 0.026 and p = 0.027, respectively).

Conclusions

LNR, which showed the best prognostic performance and significant relationship with loco-regional recurrence, can help further stratify the patients and establish an active treatment plan.

Impact of Changes in the American Joint Committee on Cancer Staging Manual, Eighth Edition, for Pancreatic Ductal Adenocarcinoma

OBJECTIVE

Consistent and reliable tumor staging is a critical factor in determining treatment strategy, selection of patients for adjuvant therapy, and for therapeutic clinical trials. The aim of this study was to evaluate the number and extent of pancreatic ductal adenocarcinoma (PDAC) cases that would have a different pT, pN, and overall stages based on the new eighth edition American Joint Committee on Cancer staging system when compared with the seventh edition.

METHODS

Patients diagnosed with PDAC who underwent pancreaticoduodenectomy, total pancreatectomy, or distal pancreatectomy from 2007 to 2017 were retrospectively reviewed. A total of 340 cases were included.

RESULTS

According to the seventh edition, the vast majority of tumors in our cohort were staged as pT3 tumors (88.2%). Restaging these cases with the new size-based pT system resulted in a more equal distribution among the 3 pT categories, with higher percentage of pT2 cases (55%).

CONCLUSIONS

The newly adopted pT stage protocol for PDAC is clinically relevant, ensures a more equal distribution among different stages, and allows for a significant prognostic stratification. In contrast, the new pN classification (pN1 and pN2) based on the number of positive lymph nodes failed to show survival differences and remains controversial.

Desmoplasia in Lymph Node Metastasis of Pancreatic Adenocarcinoma Reveals Activation of Cancer-Associated Fibroblasts Pattern and T-helper 2 Immune Cell Infiltration

OBJECTIVES

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a peritumoral proliferation of fibroblasts and extracellular matrix production known as desmoplasia. We aimed to study desmoplasia in PDAC lymph node (LN) metastases.

METHODS

We evaluated LNs from 66 patients with PDAC and LN metastases. We used immunohistochemistry and real-time polymerase chain reaction to phenotype the desmoplastic response.

RESULTS

Desmoplasia was identified in 57% of patients with LN metastases (Des+). Cancer-associated fibroblasts (CAFs) in Des+ expressed α-smooth muscle actin and collagen 11A1. The latter expression was present only in CAFs but not in LN stroma or in LN metastases without desmoplasia (Des-). Desmoplasia was associated with upregulation of transforming growth factor β messenger RNA. Whereas numbers of CD8+ in tumor vicinity were not different between Des+ and Des- patients (78 [standard deviation {SD}, 57] vs 92 [SD, 52], P = 0.48, respectively), the numbers of GATA-3+ cells, a marker of T-helper 2 immune response was significantly increased (3.7 [SD, 6.3] for Des+ vs 1.3 [SD, 2.7] for Des-, P < 0.05).

CONCLUSIONS

Lymph node desmoplasia is associated with CAF pattern activation and Th2 infiltration. Therapeutic modulation of desmoplasia may be relevant in the metastatic phase and influence antitumor immune response.

Is Routine Splenectomy Justified for All Left-Sided Pancreatic Cancers? Histological Reappraisal of Splenic Hilar Lymphadenectomy

BACKGROUND

Although splenectomy is recommended during resection for left-sided resectable pancreatic ductal adenocarcinoma (PDAC) to perform lymphadenectomy of station 10 (splenic hilum), no level I evidence justifies this procedure. This study aims to evaluate the rate of lymph node (LN) and contiguous involvement of the splenic hilum in resectable distal PDAC.

METHODS

We retrospectively reviewed all patients who underwent splenopancreatectomy for PDAC in the past 10 years. Station 10 LN were routinely isolated, and all corresponding microscopic slides were reinterpreted by a pathologist. The computed tomography (CT) results of patients with tumoral involvement of the spleen or splenic hilum by contiguity (TISOSH) and ≤ 10 mm between the tumor and spleen on pathology were blindly reviewed by two radiologists to evaluate CT for diagnosis of TISOSH.

RESULTS

We included 110 consecutive patients, including 104 with analyzable station 10 LN. The tumor was N+ in 58 (53%) patients. The median number of LN identified at station 10 was 2.0 ± 3.0. No station 10 LNs were detected in 42 (40%) patients. No patients had tumor-positive LN at station 10. TISOSH was found in nine (8%) patients, and was significantly associated with tail location (p = 0.001), tumor size (p = 0.005), and multivisceral involvement (p = 0.015). For diagnosis of TISOSH, the sensitivity and specificity of CT were respectively 89% and 95% for radiologist 1 and 89% and 100% for radiologist 2.

CONCLUSIONS

Splenic preservation during resection of distal PDAC may be an option in selected patients with body tumors and no suspected splenic or splenic hilum involvement on preoperative CT.

Accuracy of Nodal Positivity in Inadequate Lymphadenectomy in Pancreaticoduodenectomy for Pancreatic Ductal Adenocarcinoma: A Population Study Using the US SEER Database

Objectives: The optimal number of the examined lymph nodes (ELNs) in pancreaticoduodenectomy for pancreatic ductal adenocarcinoma has been widely studied. However, the accuracy of nodal positivity for the patients with inadequate lymphadenectomy is still unclear. The purpose of our study was to determine the accuracy of the number of positive nodes reported for patients with 1-3 positive nodes and the probability that 4 or more nodes could be positive along with tumor size and number of nodes examined. Methods: We obtained data on patients who underwent pancreaticoduodenectomy for resectable pancreatic ductal adenocarcinoma diagnosed during 2004-2013 from the US Surveillance, Epidemiology, and End Results registry. An mathematical model based on Hypergeometric Distribution and Bayes' Theorem was used to estimate the accuracy. Results: Among the 9,945 patients, 55.6% underwent inadequate lymphadenectomy. Of them, 1,842, 6,049, and 2,054 had T1, T2, and T3 stage disease, respectively. The accuracy of the number of observed positive nodes increased as the number of ELNs increased and the tumor size decreased. To rule out the possibility of N2 stage (4 and more positive nodes), there should be at least 13 ELNs for the patients with 1 observed positive lymph node and 14 for the patients with 2. Conclusion: Inadequate lymphadenectomy could result in underestimation of the N stage, and this would have adverse impact on recurrence, efficacy of postoperative treatment, and even overall survival. This model combined with the observed positive lymph nodes, the number of ELNs, and tumor size could provide a more accurate determination of nodal positivity of these patients.

T-Helper 1 Immune Response in Metastatic Lymph Nodes of Pancreatic Ductal Adenocarcinoma: A Marker For Prolonged Survival

BACKGROUND

Although lymph node (LN) metastases is considered a grave prognostic sign in pancreatic ductal adenocarcinoma (PDAC), patients with positive lymph nodes (PLN) constitute a heterogeneous group. Our purpose was to identify morphological and immune parameters in the primary tumor and in PLN of resected PDAC patients, which could further stratify these patients to different subgroups.

METHODS

We retrospectively evaluated histological and immunohistochemical characteristics of 66 patients with PDAC who were operated at our institution. These were subsequently correlated to clinical outcome.

RESULTS

Mean patient age and number of LN harvested was 65.5 ± 10.3 and 12.3 ± 6.5 years, respectively. Tumor size (T stage) and perineural invasion had no effect on clinical outcome. High-grade tumor was associated with decreased survival [overall survival (OS) = 19.6 ± 2.7 months for poorly differentiated PDAC vs. 31.2 ± 4 for well and moderately differentiated, p = 0.03]. Patients with ≥ 8 PLN had significantly worse outcome (OS = 7.3 ± 0.8 months for PLN ≥ 8 vs. OS = 30.1 ± 3.2 months for PLN < 8, p < 0.0001). T helper (Th) 1 immune response was measured both by its effector cells (CD8⁺) and expression of its main transcription factor, T-bet. CD8⁺ high patients had significantly increased OS compared with CD8⁺ low (OS = 36.8 ± 5.3 months for CD8 + high vs. OS = 24.3 ± 3.5 for CD8 + low, p = 0.03) Similarly, Th1 predominant immune response measured by T-bet expression was associated with improved OS compared with non-Th1 (OS = 32.8 ± 3.2 vs. OS = 19.5 ± 2.9, p < 0.0001).

CONCLUSIONS

Our data indicate an association between Th1-type immune response and increased survival. Future research is needed to exploit Th1 immune response as a biological marker for immunotherapy.

pT but not pN stage of the 8th TNM classification significantly improves prognostication in pancreatic ductal adenocarcinoma

The UICC TNM (tumour-node-metastasis) staging system for pancreatic ductal adenocarcinoma (PDAC) has been a matter of debate over decades because survival prediction based on T stages was weak and unreliable. To improve staging, the recently published 8th TNM edition (2016) introduced a conceptually completely changed strictly size-based T staging system and a refined N stage for PDAC. To investigate the clinical value of the novel TNM classification, we compared the prognostic impact of pT and pN stage between the 7th and 8th edition in two well-characterised independent German PDAC cohorts from different decades, including a total number of 523 patients. Former UICC T staging (7th edition 2009) resulted in a clustering of pT3 cases (72% and 85% of cases per cohort, respectively) and failed to show significant prognostic differences between the four stages in one of the investigated cohorts (p = 0.074). Application of the novel size-based T stage system resulted in a more equal distribution of cases between the four T categories with a predominance of pT2 tumours (65% and 60% of cases). The novel pT staging algorithm showed greatly improved discriminative power with highly significant overall differences between the four pT stages in both investigated cohorts in univariate and multivariate analyses (p < 0.001, each). In contrast, no prognostic differences were observed between the recently introduced pN1 and pN2 categories in both cohorts (p = 0.970 and p = 0.061). pT stage of resected PDAC patients according to the novel UICC staging protocol (8th edition) significantly improves patient stratification, whereas introduction of an extended N stage protocol does not demonstrate high clinical relevance in our cohorts.