Defining a minimum number of examined lymph nodes improves the prognostic value of lymphadenectomy in pancreas ductal adenocarcinoma

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.

Do pre-operative endoscopic procedures, impact the surgical outcomes of robotic pancreaticoduodenectomy?

The role and risks of pre-operative endoscopic procedures, such as endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound with fine needle aspiration (EUS/FNA), in patients undergoing robotic pancreaticoduodenectomy are not well-defined despite a broad consensus on the utility of these interventions for diagnostic and therapeutic purposes prior to major pancreatic operations. This study investigates the impact of such preoperative endoscopic interventions on perioperative outcomes in robotic pancreaticoduodenectomy. With Institutional Review Board (IRB) approval we retrospectively analyzed 772 patients who underwent robotic pancreatectomies between 2012 and 2023. Specifically, 430 of these patients underwent a robotic pancreaticoduodenectomy were prospectively evaluated: 93 (22%) patients underwent ERCP with EUS and FNA, 45 (10%) ERCP only, and 31 (7%) EUS and FNA, while 261 (61%) did not. Statistical analyses were performed using chi-square tests and Student's t-tests to compare perioperative outcomes between the two cohorts. Statistically significant differences were observed in patients who underwent a pre-operative endoscopic intervention and were more likely to have converted to an open operation (p = 0.04). The average number of harvested lymph nodes for patients who underwent preoperative endoscopic intervention was statistically significant compared to those who did not (p = 0.0001). All other perioperative variables were consistent across all cohorts. Patients who underwent endoscopic intervention before robotic pancreaticoduodenectomy were more likely to have an unplanned open operation. This study demonstrates the increased operative difficulties introduced by preoperative endoscopic interventions. Although there was no impact on overall patient outcomes, surgeons' experience can minimize the associated risks.

Centralization of Pancreaticoduodenectomy: A Systematic Review and Spline Regression Analysis to Recommend Minimum Volume for a Specialist Pancreas Service

OBJECTIVE

Through a systematic review and spline curve analysis, to better define the minimum volume threshold for hospitals to perform (pancreaticoduodenectomy) and the high-volume center.

BACKGROUND

The pancreaticoduodenectomy (PD) is a resource-intensive procedure, with high morbidity and long hospital stays resulting in centralization towards high-volume hospitals; the published definition of high volume remains variable.

MATERIALS AND METHODS

Following a systematic review of studies comparing PD outcomes across volume groups, semiparametric regression modeling of morbidity (%), mortality (%), length of stay (days), lymph node harvest (number of nodes), and cost ($USD) as continuous variables were performed and fitted as a smoothed function of splines. If this showed a nonlinear association, then a "zero-crossing" technique was used, which produced "first and second derivatives" to identify volume thresholds.

RESULTS

Our analysis of 33 cohort studies (198,377 patients) showed 55 PDs/year and 43 PDs/year were the threshold value required to achieve the lowest morbidity and highest lymph node harvest, with model estimated df 5.154 ( P <0.001) and 8.254 ( P <0.001), respectively. The threshold value for mortality was ~45 PDs/year (model 9.219 ( P <0.001)), with the lowest mortality value (the optimum value) at ~70 PDs/year (ie, a high-volume center). No significant association was observed for cost ( edf =2, P =0.989) and length of stay ( edf =2.04, P =0.099).

CONCLUSIONS

There is a significant benefit from the centralization of PD, with 55 PDs/year and 43 PDs/year as the threshold value required to achieve the lowest morbidity and highest lymph node harvest, respectively. To achieve mortality benefit, the minimum procedure threshold is 45 PDs/year, with the lowest and optimum mortality value (ie, a high-volume center) at approximately 70 PDs/year.

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.

Survival benefit and impact of adjuvant chemotherapy following systemic neoadjuvant chemotherapy in patients with resected pancreas ductal adenocarcinoma: a retrospective cohort study

BACKGROUND

Patients with pancreatic ductal adenocarcinoma (PDAC) are increasingly receiving systemic neoadjuvant chemotherapy (NAC), particularly those with borderline resectable and locally advanced disease. However, the specific role of additional adjuvant chemotherapy (AC) in these patients is unknown. The objective of this study is to further assess the clinical benefit and impact of systemic AC in patients with resected PDAC after NAC.

METHODS

Data on PDAC patients with or without AC following systemic NAC and surgical resection were retrospectively retrieved from the Surveillance, Epidemiology, and End Results (SEER) database between 2006 and 2019. A matched cohort was created using propensity score matching (PSM), and baseline characteristics were balanced to reduce bias. Overall survival (OS) and cancer-specific survival (CSS) were calculated using matching cohorts.

RESULTS

The study enrolled a total of 1589 patients, with 623 (39.2%) in the AC group and 966 (51.8%) in the non-AC group [mean age, 64.0 (9.9) years; 766 (48.2%) were females and 823 (51.8%) were males]. All patients received NAC, and among the crude population, 582 (36.6%) received neoadjuvant radiotherapy, while 168 (10.6%) received adjuvant radiotherapy. Following the 1:1 PSM, 597 patients from each group were evaluated further. The AC and non-AC groups had significantly different median OS (30.0 vs. 25.0 months, P =0.002) and CSS (33.0 vs. 27.0 months, P =0.004). After multivariate Cox regression analysis, systemic AC was independently associated with improved survival ( P =0.003, HR=0.782; 95% CI, 0.667-0.917 for OS; P =0.004, HR=0.784; 95% CI, 0.663-0.926 for CSS), and age, tumor grade, and AJCC N staging were also independent predictors of survival. Only patients younger than 65 years old and those with a pathological N1 category showed a significant association between systemic AC and improved survival in the subgroup analysis adjusted for these covariates.

CONCLUSION

Systemic AC provides a significant survival benefit in patients with resected PDAC following NAC compared to non-AC patients. Our study discovered that younger patients, patients with aggressive tumors and potentially well response to NAC might benefit from AC to achieve prolonged survival after curative tumor resection.

Impact of para aortic lymph node removal on survival following resection for pancreatic adenocarcinoma

INTRODUCTION

For PDAC patients undergoing resection, it remains unclear whether metastases to the paraaortic lymph nodes (PALN+) have any prognostic significance and whether metastases should lead to the operation not being carried out. Our hypothesis is that PALN + status would be associated with short overall survival (OS) compared with PALN-, but longer OS compared with patients undergoing surgical exploration only (EXP).

METHODS

Patients with registered PALN removal from the nationwide Danish Pancreatic Cancer Database (DPCD) from May 1st 2011 to December 31st 2020 were assessed. A cohort of PDAC patients who only had explorative laparotomy due to non-resectable tumors were also included (EXP group). Survival analysis between groups were performed with cox-regression in a multivariate approach including relevant confounders.

RESULTS

A total of 1758 patients were assessed, including 424 (24.1%) patients who only underwent explorative surgery leaving 1334 (75.8%) patients for further assessment. Of these 158 patients (11.8%) had selective PALN removal, of whom 19 patients (12.0%) had PALN+. Survival analyses indicated that explorative surgery was associated with significantly shorter OS compared with resection and PALN + status (Hazard Ratio 2.36, p < 0.001). No difference between PALN + and PALN- status could be demonstrated in resected patients after controlling for confounders.

CONCLUSION

PALN + status in patients undergoing resection offer improved survival compared with EXP. PALN + should not be seen as a contraindication for curative intended resection.

Lymph node ratio is a superior predictor in surgically treated early-onset pancreatic cancer

Background

The prognostic performance of four lymph node classifications, the 8th American Joint Committee on Cancer (AJCC) Tumor Node Metastasis (TNM) N stage, lymph node ratio (LNR), log odds of positive lymph nodes (LODDS), and examined lymph nodes (ELN) in early-onset pancreatic cancer (EOPC) remains unclear.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database was searched for patients with EOPC from 2004 to 2016. 1048 patients were randomly divided into training (n = 733) and validation sets (n = 315). The predictive abilities of the four lymph node staging systems were compared using the Akaike information criteria (AIC), receiver operating characteristic area under the curve (AUC), and C-index. Multivariate Cox analysis was performed to identify independent risk factors. A nomogram based on lymph node classification with the strongest predictive ability was established. The nomogram’s precision was verified by the C-index, calibration curves, and AUC. Kaplan–Meier analysis and log-rank tests were used to compare differences in survival at each stage of the nomogram.

Results

Compared with the 8th N stage, LODDS, and ELN, LNR had the highest C-index and AUC and the lowest AIC. Multivariate analysis showed that N stage, LODDS, LNR were independent risk factors associated with cancer specific survival (CSS), but not ELN. In the training set, the AUC values for the 1-, 3-, and 5-year CSS of the nomogram were 0.663, 0.728, and 0.760, respectively and similar results were observed in the validation set. In addition, Kaplan–Meier survival analysis showed that the nomogram was also an important factor in the risk stratification of EOPC.

Conclusion

We analyzed the predictive power of the four lymph node staging systems and found that LNR had the strongest predictive ability. Furthermore, the novel nomogram prognostic staging mode based on LNR was also an important factor in the risk stratification of EOPC.

The role of coeliac axis resection in resected ductal adenocarcinoma of the distal pancreas: A result of tumour topography or a prognostic factor?

BACKGROUND

Whether coeliac axis resection (CAR) results from tumour topography or a prognostic factor for distal pancreatic ductal adenocarcinoma (PDAC) remains unclear. We aimed to compare the clinicopathological data between distal pancreatectomy with en bloc CAR (DP-CAR) and distal pancreatectomy plus splenectomy (DP-S) and analyse the prognostic factors.

METHODS

We retrospectively analysed clinicopathological data from 102 patients who underwent distal pancreatectomy for PDAC and the factors affecting disease-free survival (DFS) and overall survival (OS). Of these patients, 45 and 57 underwent DP-CAR and DP-S, respectively.

RESULTS

DP-CAR was associated with more operative challenges than DP-S: more portomesenteric vein resections (48.9% vs. 14.0%), longer operations (320 vs. 242 min), and greater estimated blood loss (EBL) (600 vs. 200 ml). DP-CAR had larger tumours (5 vs. 4 cm), more perineural invasion (91.1% vs. 73.7%), and more microscopically positive surgical margins (20% vs. 3.5%), compared to DP-S. The major complication was clinically relevant postoperative pancreatic fistula (20.6%). The median DFS was 15.8 months and the median OS was 20.1 months. CAR was not associated with DFS or OS. EBL>700 ml, lymphovascular invasion (LVI), and adjuvant chemotherapy independently affected DFS and OS.

CONCLUSION

DP-CAR was associated with larger tumours and more surgical challenges but not with poorer DFS and OS than DP-S. CAR was more likely to result from tumour topography rather than from an adverse prognostic factor for resected distal PDAC. EBL>700 ml, LVI, and adjuvant chemotherapy were independent factors affecting the survival of patients with distal PDAC who underwent surgical resection.

Evaluation of nodal status in intrahepatic cholangiocarcinoma: a population-based study

Background

Lymph node metastasis (LNM) is a well-established prognostic factor for intrahepatic cholangiocarcinoma (ICC), but there are still some controversies relating to the evaluation of nodal status. Therefore, we investigated the role of lymph node dissection (LND), compared the prognostic performances of different nodal staging systems, and then developed and validated a nomogram to predict cancer-specific survival (CSS) of ICC patients.

Methods

The study cohort was taken from the Surveillance, Epidemiology, and End Results database. Akaike information criterion, Bayesian information criterion, Harrell's C-index and area under the receiver operating characteristic curves were calculated to evaluate the different staging models. The nomogram for the CSS was constructed based on Cox regression models and validated by calibration curves. Decision curve analysis was introduced to examine the clinical value of the models.

Results

A total of 664 patients were enrolled, and 331 (51.4%) patients underwent LND. An increasing number of lymph nodes retrieved showed no oncologic benefit (P=0.876). LNM was identified in 103 (31.1%) patients, which was the cause of their poor prognoses (5-yr CSS 13.1% versus 44.9%, P<0.001). Patients without LNM could not benefit from adjuvant therapy after propensity score matching (P=0.140). Based on the Youden index, 4 or more lymph nodes retrieved might be adequate for accurate staging. The lymph node ratio (LNR) classification, with an optimal cut-off value of 0.15, displayed the best prognostic performance. Age, size, tumor number, T Stage, grade and the LNR classification were independent predictive factors for the CSS in ICC patients. The nomogram for predicting the CSS of ICC patients according to the independent factors was well calibrated and it showed better discrimination power and higher net benefits than the American Joint Committee on Cancer (8th edition) staging system.

Conclusions

LNM is an independent prognostic factor in ICC. Although it shows no oncologic benefits, LND should still be considered as a method of stratifying patients, with 4 or more lymph nodes retrieved potentially enough to do so. LNR appears to be a promising and easy-to-use prognosticator for nodal staging. The constructed nomogram could serve as an effective tool to predict the CSS probabilities of ICC patients.

Lymph Node Metastatic Patterns and Survival Predictors Based on Tumor Size in Pancreatic Ductal Adenocarcinoma

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies. Larger tumor size is widely acknowledged to be associated with increased lymph node (LN) metastatic potential. However, the quantitative relationships between tumor size and LN metastasis or survival remain unclear. This study aims to quantify the objective relationship between tumor size and the prevalence of LN metastases across a spectrum primary tumor size.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to identify 9958 patients with resected PDAC without distant metastasis. The prevalence of LN metastases, LN ratio (LNR), and N2/N1 ratio were assessed amongst different tumor sizes, and the relationships were displayed by matched curves.

RESULTS

In the enrolled cohort, age, tumor site, grade, American Joint Committee on Cancer (AJCC) 8th node staging, tumor size, chemotherapy, and radiotherapy were identified as significant independent predictors for overall survival (OS) and cancer-specific survival (CSS). For tumors within 1-40 mm in size, the prevalence of node-positive disease is closely modelled using a logarithmic formula [0.249 × ln (size) + 0.452] × 100%. The prevalence plateaued between 70% and 80% beyond 40 mm. The mean LNR increased in a stepwise manner as tumor size increased from 1-5 mm (LNR = 0.024) to 41-45 mm (LNR = 0.177); then, beyond 45 mm, it plateaued near 0.170. N2/N1 ratio gradually increased along with tumor size from 1-5 mm (N2/N1 = 0.286) to 41-45 mm (N2/N1 = 1.016), and when tumor size reached to 41-45 mm or more, the ratio stabilized around 1.000. In addition, significant survival prediction by AJCC N staging was observed when tumors ranging between 16 and 45 mm in size.

CONCLUSION

Regional LN involvement demonstrated a logarithmic growth with increasing tumor sizes in patients with resected PDAC . The probability of metastasis in each regional LN for resected PDAC with tumors greater than 40 mm in size was near 17.0% and their overall prevalence of LN metastasis was 70-80%. Among which, 50% of patients had an N2 stage. Such prediction may be a potential and promising tool for guiding lymphadenectomy in PDAC surgery.